GB2639614A

GB2639614A - Pipe part for connecting to a subsea foundation

Info

Publication number: GB2639614A
Application number: GB2403928.1A
Authority: GB
Inventors: Reinås Lorents; Einar Ellingsen Kjell; Stangeland Jone; Gundersen Fuhr Geir; Sigurd Nesse Harald
Original assignee: Equinor Energy AS
Current assignee: Equinor Energy AS
Priority date: 2024-03-19
Filing date: 2024-03-19
Publication date: 2025-10-01
Also published as: GB202403928D0; GB2639614A8; WO2025198476A1

Abstract

Disclosed is a pipe part 12 for connecting to a subsea foundation 1, wherein the pipe part comprises a pipe and a plug 13, wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe.

Description

PIPE PART FOR CONNECTING TO A SUBSEA FOUNDATION

The invention relates to a pipe part for connecting to a subsea foundation, a subsea foundation comprising the pipe part, a method of providing the pipe part and a method of using the pipe part.

Many subsea devices, such as a subsea well and associated wellhead equipment, require a foundation on which they can be located during use. For example, a subsea well assembly will generally comprise a foundation. The foundation is used to support the subsea well which extends into the seabed and the wellhead equipment such as a blowout preventer.

A known type of subsea foundation is the suction anchor. A suction anchor used as a subsea foundation, comprises a skirt. The suction anchor is lowered onto the seabed and then sucked into the seabed by reducing the pressure inside the skirt. Once the suction anchor has been sucked into the sea bed, the suction anchor may provide a foundation for a well or another subsea device.

It has been found that in certain circumstances, such as when the subsea foundation is a suction anchor, it may be beneficial if the subsea foundation further comprises a pipe extending therefrom.

It is known from WO 2017/179992 to provide a subsea foundation comprising a suction anchor with a two-part inner member. In this case the lower part of that member protrudes from the suction skirt of the suction anchor and is attached to the suction anchor at the installation site. This is achieved by first placing the lower part on the seabed, then deploying the suction anchor subsea, next connecting a pull-in line between the lower part and the suction anchor, and then connecting the lower part to the upper part subsea using a pull-in line through the centre of the inner member.

WO 2021/040533 discloses further subsea foundation systems comprising: a subsea foundation; an upper pipe portion connected to the subsea foundation, and a lower pipe portion. The subsea foundation is arranged such that when subsea, the lower pipe portion can be connected to the upper pipe portion. This document also discloses methods of connecting the lower pipe portion to the subsea foundation such as via a pull-in arrangement.

It has been realised that the pipe part for connection to the subsea foundation may have additional features that allow the provision of alternative and/or improved subsea foundation systems.

In a first aspect the present invention may provide a pipe part for connecting to a subsea foundation, wherein the pipe part comprises a pipe and a plug, wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe.

It has been realised that the pipe part can be provided with a plug that has the function of guiding tools or equipment located within the pipe or extending through the pipe. This may be when the tools or equipment contact the upper surface of the plug. The shaped upper surface may guide the tools or equipment within the pipe to a certain position, such as a central position. Thus, when tools or equipment are inserted into the pipe and/or come into contact with the upper surface of the plug, the plug can act as a guide for the tools or equipment.

This may be achieved by, when the tools or equipment are inserted into the pipe, the plug is arranged so the tools or equipment come into contact with at least a portion of the upper surface of the plug. The shape of the upper surface of the plug may then guide the tool or equipment to a certain desired position, such as a central position.

The plug may also have the function of preventing material, such as soil, entering the pipe during installation of the pipe and/or subsea foundation. If the pipe houses other equipment such as sensors, other instruments, conduits, guides, and/or casings etc the plug may have the function of protecting that housed equipment during installation of the pipe and/or subsea foundation. In this case, the plug may be a solid plug. Alternatively, the plug may have one or more passages therethrough. This passage(s) may allow tools and equipment to extend through the plug.

The tools or equipment that may be guided by the plug include a drill string, conduit, drilling guide, casing and/or bottom hole assembly (BHA) for example. The plug, and specifically the shaped upper surface of the plug, may act as a centraliser. The plug may be referred to and/or act as a drill string centraliser, a conduit centraliser, a casing centraliser and/or BHA centraliser. The plug may for example, be used to help align a high pressure wellhead, conduit and/or casing that is located on or within the pipe. In other words, the shaped upper surface may be configured to guide the tools or equipment within the pipe towards the central axis of the pipe.

Alternatively, the plug, and specifically the shaped upper surface of the plug, may be arranged to guide the tools or equipment in a direction that is not coaxial with the central axis of the pipe part. This may be for example if the pipe part is to be used as part of a deviated well. In this case it may be desirable for the plug to guide the tools and equipment, e.g. drill string and/or components, in a non-central and/or non-straight direction.

Additionally, or alternatively, the upper surface of the plug may be shaped to provide a pilot hole. The pilot hole may act as a guide for a drill. The plug may guide and correctly locate the bottom of the drill string. This may thus aid guiding and correctly locating a reamer higher up the drill string. This may for example allow drilling to be straight (i.e. parallel to the axis of the pipe). This may be achieved by the shaped upper surface having one or more recesses. The one or more recesses may each act as a pilot hole.

The recess, i.e. pilot hole, may be configured to guide drilling in a non-straight direction (e.g. non-coaxial and non-parallel to the central axis direction). This may be for example if the pipe part is to be used as part of a deviated (i.e. non-vertical) well.

The plug may have a non-flat upper surface, i.e. the shaped upper surface may be a non-flat surface.

The plug may have a concave upper surface, i.e. shaped upper surface may be an at least partly concave surface. This may for example be a concave conical, pyramidal or recessed upper surface. In the case that the upper surface is a concave conical or pyramidal upper surface, the apex of the cone or pyramid may be at the desired guiding location, such as the centre of the pipe. This may be so that when a tool or equipment is inserted into the pipe, when it comes into contact with the upper surface of the plug it may slide or be guided by the upper surface to a certain, e.g. central, location.

The upper surface may be frustoconical or frustopyramidal and/or have a frustoconical or frustopyramidal surface. The circumferentially outer upper surface of the plug may be frustoconical or frustopyramidal. This may mean that when tools or equipment are inserted into the pipe they are guided at least partly towards the centre of the pipe and/or away from the inner surface of the pipe.

The upper surface of the plug may have one or more recessed portions. This recessed portion(s) may for example be configured to act as a pilot hole to guide drilling that may occur within and/or through the pipe. The recessed portion(s) may for example be a cylindrical recess. The recess may be an inner or central recess and may be located towards or at the centre of the plug and/or pipe part. The cross-sectional shape of the recess may be symmetrical. This may be symmetrical about a plane extending through the central axis of the pipe part.

The central axis of the recess may be parallel to and/or coaxial with the central axis of the pipe. This may mean that the shaped upper surface of the plug is configured to guide a drill string in a direction that is parallel to and/or coaxial with the central axis of the pipe.

The upper surface of the plug may be or comprise one or more of a conical surface, pyramidal surface, frustoconical surface, frustopyramidal surface, concave surface, recessed surface, non-flat surface etc. The plug may have a symmetrical upper surface. The upper surface may be symmetrical about one or more planes through the central axis of the pipe. In one example, the upper surface may have a concave frustoconical upper circumferentially outer surface that bounds an inner (e.g. cylindrical) recess. In this case the concave frustoconical upper circumferentially outer surface may be arranged to, in use, guide tools and equipment, such as a drill string, towards the inner recess, which in use may be arranged to act as a pilot hole.

The plug may have a non-symmetrical upper surface. This may be when the plug is configured to guide tools and equipment in a non-straight direction, e.g. in the case of a deviated well.

The plug may be designed to be drilled through. The plug may be made of a material that can be drilled through, such as concrete. The plug may be made of or comprise cement, cast iron, aluminium, plastic, polymers etc. It may be made of any material that can withstand the forces exerted on it if the pipe part is forced into the seabed whilst being able to be drilled through as necessary after it has been forced into the seabed. Thus the plug may be a concrete plug. A plug made of concrete may be chosen because concrete is a relatively cheap material.

The material of the plug may be the same material as is used in the cementing of standard known wells.

The plug may be arranged to allow air and water to pass therethrough but not soil, e.g. there may be small holes in the plug. This may aid installation in a subsea system.

When the pipe and hence plug has been drilled through, some of the plug may remain within the pipe. This is because the outer diameter of the drill bit may be smaller than the inner diameter of the pipe and/or the outer diameter of the drill bit may be smaller than the outer diameter of the plug. The retained part of the plug for example would be the circumferentially outermost part of the plug. This retrained part of the plug may for example be 1 or 2 inches thick from the surface of the pipe. This retained part of the plug left after drilling through the pipe and plug may also be shaped so that in use it is configured to act as a guide for tools or equipment located within or extending through the pipe. This is because this part of the plug may have a shaped upper surface, such as frustoconical or frustopyramidal upper surface, so as to guide tools or equipment towards the hole drilled through the plug.

The plug may be at least partially housed within the pipe. Thus the plug may be referred to as an internal plug.

The upper surface of the plug may be located within the pipe.

The upper surface may be the surface that faces an open end of the pipe. The upper surface of the plug may face the upper end of the pipe and the lower surface may face or protrude from the bottom end of the pipe. This open/upper end of the pipe may be an end into which tools or equipment can be inserted.

When the pipe part is connected to a subsea foundation, the top of the pipe may be the end closer to the subsea foundation and the bottom of the pipe may be the end further from the subsea foundation. Thus the top may be the proximal end and the bottom may be the distal end relative to the subsea foundation.

The plug may be located within the bottom half of the pipe. The plug may be at or towards one end, e.g. the bottom end, of the pipe. The plug may fill less than 25%, or less than 10% of the total volume of the pipe.

The plug may be located entirely within the pipe.

Alternatively, the plug, e.g. internal plug, may at least partly protrude from one end, e.g. the bottom, of the pipe. The plug may protrude from the end of the pipe that in use will contact the seabed first as the pipe part and/or subsea foundation is installed in the seabed.

The lower surface of the plug may be shaped to act as a guide. This may be a guide for installation. For example, the lower surface of the plug may be shaped to assist locating the pipe into its installation position. For example the lower surface of the plug may act to guide the pipe into a predrilled or preformed hole in the seabed. Additionally or alternatively, the lower surface of the plug may act to aid penetration into the seabed, e.g. if the pipe is forced into the seabed such as by piling or suction. This is because the lowermost surface of the plug may have a surface area that is smaller than if the plug had a flat lower surface, e.g. a lower surface that has the same diameter as the pipe.

The lower surface of the plug may have a symmetric shape. This may be symmetric with respect to the longitudinal axis of the pipe part. This may be so that the plug also does not generate any sideways force if the pipe is forced into the seabed, i.e. during soil penetration.

The lower surface of the plug may be the opposite surface of the plug to the upper surface.

The lower surface of the plug may be a non-flat surface. For example, the lower surface of the plug may be a convex surface. The lower surface of the plug may be a convex surface such as a domed, conical, pyramidal, frustoconical or frustropyramidal surface etc. The pipe part may be referred to as a tail pipe.

The pipe part (comprising the plug) may be connected and/or for connection to a subsea foundation.

In a second aspect the present invention may provide a subsea foundation system, the subsea foundation system comprising a pipe part wherein the pipe part comprises a pipe and a plug, wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or through the pipe.

The pipe part of the subsea foundation system of second aspect may be the pipe part of the first aspect described above and may have one or more or all of the above described features, including optional features.

Thus the present invention may provide a subsea foundation system, the subsea foundation system comprising a pipe part according to the first aspect of the invention (including one, or more or all of the optional features) The subsea foundation system may comprise a subsea foundation. The pipe part may be for connection to the subsea foundation. The pipe part may be connected to the subsea foundation. The pipe part may be directly connected to the subsea foundation. When the pipe part is connected to the subsea foundation it may protrude beyond the bottom of the subsea foundation.

This means that when the subsea foundation system is lowered towards the seabed the pipe part may contact and penetrate the seabed before the subsea foundation, e.g. before the suction skirt of a suction anchor, if present. This may facilitate the installation of the subsea foundation on the seabed.

The lower pipe portion may be connected to the subsea foundation when the subsea foundation, e.g. suction anchor, is subsea but before it reaches the seabed. For example, the subsea foundation may be located above the water and/or seabed whilst the pipe part is connected to the subsea foundation.

The subsea foundation system may comprise an upper pipe portion connected to the subsea foundation. The pipe part, i.e. that of the first aspect (which may be referred to as a lower pipe part), may be for connection to or connected to the upper pipe portion.

The upper pipe portion may not protrude beyond the bottom of the subsea foundation.

The subsea foundation may comprise a suction anchor. The upper pipe portion (if present) and/or pipe part may be connected (optionally directly connected) to the suction anchor.

If the foundation is a suction anchor, the pipe part may form at least part of a centre pipe of the suction anchor that runs through the suction skirt and around which is an annular suction volume of the suction anchor. The pipe part may be used to extend the centre pipe of the suction anchor beyond the bottom of the suction skirt.

The subsea foundation, (e.g. suction anchor), upper pipe portion (if present), and pipe part together may form at least part of a subsea foundation system.

The subsea foundation may be a foundation for a subsea well. This may for example be an exploration well, a keeper well, a production well or relief well etc. The subsea well may be for accessing a subterranean formation and/or may be for extracting hydrocarbons Thus the subsea foundation may be a subsea well foundation. The well may be an oil and/or gas well.

The pipe part may provide at least part of a pipe for a well, e.g. a conductor and/or a casing.

When the foundation comprises a suction anchor, the upper pipe (if present) and/or the pipe part may extend through the suction anchor within the suction skirt.

The upper pipe, if present, and/or pipe part (e.g. lower pipe when connected to the upper pipe) may for example provide at least part of a central pipe of a suction anchor.

The present invention may provide, a subsea well foundation, the foundation comprising: a suction anchor, the suction anchor comprising an inner pipe for a well and an outer suction skirt located around/about the inner pipe, wherein the inner pipe comprises at least the pipe part.

Deployment of the subsea foundation subsea may mean that the subsea foundation is moved from a location above the water to a location under the surface of the water.

The subsea foundation being for deployment subsea may mean that it is suitable for deploying subsea and hence has not yet been deployed subsea. Thus, it is in a state that has not yet been deployed subsea.

The term 'subsea foundation' does not mean that the foundation is necessarily subsea, but rather that in use it will be subsea, i.e. it is to be, and arranged to be, used subsea.

In a third aspect the present invention may provide a method of providing a pipe part for a subsea foundation system, wherein the pipe part comprises a pipe and a plug, the method comprising: providing the pipe and providing the plug within the pipe, wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe.

The pipe part of the method of third aspect may be the pipe part of the first aspect described above and may have one or more or all of the above described features, including optional features.

The subsea foundation of the method of third aspect may be the subsea foundation of the second aspect described above and may have one or more or all of the above described features, including optional features.

Thus the present invention may provide a method of providing a pipe part according to the first aspect of the invention (including one, or more or all of the optional features), the method comprising providing the pipe and providing the plug within the pipe. The pipe part may be for use with and/or part of a subsea system according to the second aspect (including one, or more or all of the optional features).

The plug may be provided within the pipe when the pipe part is onshore, i.e. not subsea. In other words, the plug may be formed and/or shaped within the pipe when the pipe part is onshore. This may be when the pipe part is connected to the subsea foundation. Alternatively, the plug may be formed and/or shaped before the pipe part is connected to the subsea foundation. This may make the forming of the plug easier.

This may allow the plug, including the upper and/or lower surface of the plug to be made and/or shaped more easily and/or accurately compared to a system in which the plug is made and formed subsea. This may allow the guiding function of the plug to be more precise compared to a system in which the plug is made subsea.

The plug, e.g. concrete plug, may be cast in the pipe, e.g. onshore. The plug may be formed and/or shaped using one or more moulds. The upper and/or bottom surface of the plug may be formed and/or shaped using a mould. The upper and/or lower surface of the plug may additionally or alternatively be shaped by machining, e.g. onshore. This may be performed by inserting a machining tool into the pipe through the open end of the pipe (e.g. the end distal from the plug).

The pipe part may be made from two or more pipe pieces joined, e.g. welded, together. Thus, the pipe part may be formed from two or more shorter pipe pieces. This may make manufacture of the pipe part easier, quicker and/or cheaper.

For example, the plug may be formed inside a first pipe piece which is then joined, e.g. welded, to another pipe piece to form the pipe part. The first pipe piece may be a relatively short pipe piece, e.g. less than half the total length of pipe part.

The plug may be formed in the first pipe piece when the first pipe piece is in a vertical position. For example, the material for forming the plug may be poured into the pipe piece when it is vertical. The material for forming the plug may be moulded and/or machined to the desired shape when the first pipe piece is vertical. Once the plug has been formed in the first pipe piece, the first pipe piece may be connected to, e.g. welded to, the second pipe piece. The first pipe piece may be connected to the second pipe piece when in a non-vertical, e.g. horizontal position.

This is because this position is an easier position in which to handle a long pipe part.

This may ease manufacture of the pipe part comprising the plug. This is because the shorter pipe piece may be easier to handle, work with, and/or manipulate for forming the plug therein.

In a fourth aspect the present invention may provide a method of guiding a tool or equipment in a pipe part of a subsea foundation system, the method comprising providing the pipe part, wherein the pipe part comprises a pipe and a plug, wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe; and inserting the tool or equipment into the pipe and using the upper surface of the plug to at least partly guide the location of the tool or equipment.

The pipe part of the method of fourth aspect may be the pipe part of the first aspect described above and may have one or more or all of the above described features, including optional features.

The subsea foundation of the method of fourth aspect may be the subsea foundation of the second aspect described above and may have one or more or all of the above described features, including optional features.

The step of providing the pipe part of the fourth aspect may be the method of the third aspect (including one or more or all of the optional features).

Thus the present invention may provide a method of guiding a tool or equipment in a pipe part of the first aspect (including one or more or all of the optional features) of a subsea foundation system of the second aspect (including one or more or all of the optional features), the method comprising providing the pipe part according to the method of the third aspect (including one or more or all of the optional features); and inserting the tool or equipment into the pipe and using the upper surface of the internal plug to at least partly guide the location of the tool or equipment.

The method may comprise inserting a drill into the pipe and the method may comprise using the plug to guide the location of the drill.

The method may comprise drilling through the plug. As described above, when the plug has been drilled through, some of the plug may remain within the pipe. This may be referred to as a retained part of the plug. As also described above, this retained part of the plug left after drilling through the pipe and plug may also be shaped so that in use it is configured to act as a guide for tools or equipment located within or extending through the pipe.

The method may comprise using the upper surface of the retained part of the plug to at least partly guide the location of tools or equipment located within or extending through the pipe. This may be done after the drill string has been removed from the pipe. The method may comprise inserting a different tool or equipment other than the drill string, such as a casing, other conduit, drilling guide, or BHA, and using the remaining plug to guide this tool or equipment.

It has been realised that it may be beneficial for the pipe part to comprise an orientation guide to facilitate the pipe part being installed in a particular orientation.

This may for example be useful if the plug is not symmetrical. This may mean for example that it is desired for the plug to be installed in a particular orientation.

It has been realised that the orientation guide may be useful even if the pipe part does not comprise a plug as described above and/or comprises a plug for which the orientation of the pipe part does not matter, e.g. a symmetrical plug. This is because the pipe part (or subsea foundation to which the pipe part connects) may have another feature or component that it is desired to install in a particular orientation. This may for example be deviated (i.e. bent, curved, slanted etc.) internal casing(s), deviated drilling guide and/or instruments and sensors etc. Thus in a fifth aspect the present invention may provide pipe part for connecting to a subsea foundation, wherein the pipe part comprises an orientation guide to facilitate the pipe part being installed in a particular orientation.

The orientation guide may comprise an external orientation guide. This may be an orientation guide that can be seen during installation of the pipe part and/or can be seen during connection of the pipe part to a subsea foundation system.

The orientation guide may comprise a visual orientation guide. This may mean that the orientation guide is a distinctive item on the pipe, such as a mark and/or differently coloured part compared to the rest of the pipe part that can be seen, e.g. by a person and/or an underwater camera, during installation of the pipe part. For example, the visual orientation guide may comprise an orange mark or orange part of the pipe part. It has been found that an orange orientation guide may be more easily visible subsea compared to other colours.

The orientation guide may comprise a mechanical orientation guide. This may be internal or external of the pipe part. The mechanical orientation guide may be configured to only allow the pipe part to be connected to the subsea foundation system in a particular orientation.

The mechanical orientation guide may for example comprise a lug on one part and recess for receiving the lug on the other part. The lug and recess may be configured to only allow the pipe part and the subsea foundation to be connected together in the particular orientation.

The orientation guide may comprise an electronic orientation guide. For example, the orientation guide may comprise an orientation sensor and optionally a transmitter. The orientation sensor may be used to determine the orientation of the pipe part. Data from the orientation sensor may be used during installation.

The particular orientation may be a predetermined and/or desired orientation.

The orientation guide may be for facilitating the pipe part being connected to the subsea foundation in particular orientation and/or may be to facilitate the pipe part (and hence subsea foundation once they are connected together) being installed in a particular orientation relative to the seabed (and hence relative to geological formations under the seabed).

The orientation guide may be configured to facilitate the pipe part being connected to the subsea foundation in a particular orientation. This may for example be desirable if the pipe part comprises internal components (e.g. non-symmetrical internal components), such as one or more, conduits, casings and/or instruments such as sensors, that it is desired to be connected to the subsea foundation in a particular orientation.

The orientation guide may be configured to facilitate the pipe part being installed in a particular orientation relative to the seabed. This may for example be desirable if the pipe part comprises internal components, such as one or more deviated casings, drilling guide, and/or instruments such as sensors, that it is desired to be located in a particular location in the seabed, e.g. located in a direction towards a geological formation.

When the pipe part comprises internal components, e.g. those which cannot be seen during installation of the pipe part (e.g. during connection of the pipe part to the subsea foundation and/or during installation of the pipe part into the seabed), the location and orientation of the internal components relative to the orientation guide may be known. This means that the orientation guide may be used to facilitate the internal components of the pipe part being installed in a particular orientation.

In a sixth aspect the present invention may provide a subsea foundation system comprising: a pipe part for connecting to a subsea foundation; and a subsea foundation, wherein the pipe part comprises an orientation guide to facilitate the pipe part being installed in a particular orientation.

The pipe part of the subsea foundation system of sixth aspect may be the pipe part of the fifth aspect described above and may have one or more or all of the above described features, including optional features.

Thus the present invention may provide a subsea foundation system, the subsea foundation system comprising a pipe part according to the fifth aspect of the invention (including one, or more or all of the optional features).

The pipe part may be connected to the subsea foundation. The pipe part may be directly connected to the subsea foundation. When the pipe part is connected to the subsea foundation it may protrude beyond the bottom of the subsea foundation.

When the pipe part is connected to the subsea foundation the orientation guide may be located beyond the bottom of the subsea foundation and/or be visible from an external location, e.g. by an underwater camera located next to the subsea foundation.

This means that when the subsea foundation system is lowered towards the seabed the pipe part may contact and penetrate the seabed before the subsea foundation, e.g. before the suction skirt of a suction anchor, if present and the orientation guide may be visible. This may facilitate the installation of the subsea foundation on the seabed in a particular orientation.

The pipe part may be connected to the subsea foundation when the subsea foundation, e.g. suction anchor, is subsea but before it reaches the seabed. The orientation guide may be used to connect the pipe part and the subsea foundation together in a particular orientation even when the connection occurs subsea.

The subsea foundation may comprise an orientation guide. The orientation guide on the subsea foundation may be a complementary and/or corresponding orientation guide to the orientation guide on the pipe part. The orientation guide of the pipe part may be referred to as a first orientation guide and the orientation guide of the subsea foundation may be referred to as a second orientation guide. The second orientation guide may be used to facilitate the pipe part being installed in a particular orientation, e.g. a particular orientation relative to the subsea foundation.

The first orientation guide and second orientation guide may be complementary.

The subsea foundation system may be arranged such that when the first orientation guide and the second orientation guide are aligned, or otherwise located in a certain position relative to each other, the pipe part will be in a particular orientation relative to the subsea foundation.

If the first orientation guide comprises a visual orientation guide, the second orientation guide may comprise a corresponding visual orientation guide. For example, if the first orientation guide comprises a certain coloured mark or part the second orientation guide may comprise a same coloured mark or part. For example the first orientation guide and the second orientation guide may both comprise an orange mark or part.

If the orientation guide of the pipe part (i.e. first orientation guide) comprises a mechanical orientation guide, the subsea foundation system may comprise a complementary and/or corresponding mechanical orientation guide (i.e. second orientation guide).

The first orientation guide and the second orientation guide may be configured so that the pipe part can only be connected to the subsea foundation in a particular orientation. This may aid providing a fool-proof system in which the pipe part cannot be connected to the subsea foundation in a wrong orientation. The subsea foundation system may comprise a pull-in arrangement for connecting the pipe part to the subsea foundation. Thus the subsea foundation system may be arranged such that subsea the pipe part can be connected to the subsea foundation using the pull-in arrangement. The orientation guide may be part of the pull-in arrangement. Thus the pull-in arrangement may be configured to facilitate installing the pipe part in a particular orientation.

The pull-in arrangement may comprise one or more pull-in lines that are used to pull the pipe part into connection with the subsea foundation. Each pull-in line may be connected at one end to the subsea foundation and at the other end to the pipe part. The system may be arranged so that shortening or otherwise pulling on the pull-in lines pulls the pipe part towards the subsea foundation such that the pipe part can be connected to the subsea foundation When pull-in arrangement comprises the orientation guide, this may be achieved by there being some form of guide, such as mark, to allow one end of the pull-in line to be connected to the pipe part at a particular single location on the pipe part and the other end to be connected to the subsea foundation at another particular single location on the subsea foundation. This means that when the pull-in arrangement is used to connect the pipe part to the subsea foundation, the pipe part will be connected to a subsea foundation in a particular orientation The orientation guide, e.g. coloured parts, may be configured to help ensure that the pull-in line is connected to the correct pull-in line connection point to achieve the particular orientation.

The pipe part may comprise one or more pull-in line connection point(s). The connection points may be located off-centre. The system may comprise a pull-in line connection point for each pull-in line. These may for example be pull-in line connection wing(s). The pull-in line connection wing(s) may extend radially outward from the lower pipe portion. This is so that the pull-in line(s) may be radially spaced from the lower pipe portion.

The pull-in line connection point, (or one (i.e. only one) of the pull-in line connection points if there are more than one pull-in line connection points) may comprise the orientation guide.

For example, the pipe part may comprise two pull-in line connection points and only one of them may comprise the orientation guide. This may for example be a visual orientation guide, such as the pull-in line connection point being a particular colour, e.g. orange, that is different from the other pull-in line connection point. The pull-in line connection point that comprises the orientation guide may still be visible from an external location even once the pipe part and the subsea foundation are connected. Thus it may be used to guide installing the pipe part and hence foundation in a particular orientation in the seabed.

For example, the pipe part may comprise a pull-in line connection wing that is configured to be an orientation guide. For example, the pipe part may comprise one pull-in line connection wing that is a different colour, e.g. orange, compared to the other pull-in line connection wing(s).

The subsea foundation may comprise one or more pull-in lines. One (e.g. only one) of the pull-in lines (or associated component) may comprise an orientation guide. For example, one pull-in line (or associated component, such as a guide conduit through which the pull-in line extends) may be the same colour as one of the pull-in line connection points on the pipe part. This may mean that a particular pull-in line may be connected to a particular pull-in connection point on the pipe part. Hence when the pipe part is pulled in to connection with the subsea foundation, the two components may be connected together in a particular (i.e. predetermined) orientation.

The pipe part may comprise internal components such as one or more casings, drilling guides, and/or instruments (e.g. sensors) that require the pipe part to be connected to the subsea foundation in a particular orientation. This may be so that the casing(s) and/or drilling guides can be aligned with components such as wellheads provided with the subsea foundation and/or instruments can be connected to signal or power sources in the subsea foundation etc. The orientation guide may be used to both connect the pipe part to the subsea foundation in a particular orientation and install the pipe part and hence subsea foundation in a particular orientation on the seabed. This may be so that components in the pipe part are located in a particular orientation compared to components in the subsea foundation when the two are connected together and then the components in the pipe part and/or subsea foundation can be installed in the seabed in a particular orientation relative to features of the seabed such as geological formations etc. Thus the orientation guide may have a dual function.

The subsea foundation system may comprise an upper pipe portion connected to the subsea foundation. The pipe part, i.e. that of the fifth aspect (which may be referred to as a lower pipe part), may be for connection to or connected to the upper pipe portion. The orientation guide may be used to facilitate connection of the pipe part to the upper pipe portion in a particular orientation. The upper pipe portion (if present) may comprise the second orientation guide.

The subsea foundation may be a foundation for a subsea well. Thus the subsea foundation may be a subsea well foundation. The well may be an oil and/or gas well.

The pipe part may provide at least part of a pipe for a well, e.g. a conductor and/or a casing. In other words the pipe part may function as a portion of a well conductor. In use, the pipe may be forced into the seabed, put into a formed (e.g. drilled) borehole that is substantially the same diameter as the outer diameter of the pipe, or put into a formed (e.g. drilled) borehole that is larger than the outer diameter of the pipe and then cemented in the hole in the seabed.

In a seventh aspect the present invention may provide a method of installing a pipe part, wherein the pipe comprises an orientation guide to facilitate the pipe being installed in a particular orientation, the method comprising: providing the pipe part; providing a subsea foundation; connecting the pipe part to the subsea foundation; and using the orientation guide to install the pipe part in the particular orientation.

The step of using the orientation guide to install the pipe part in the particular orientation may comprise using the orientation guide to connect the pipe to the subsea foundation in a particular orientation and/or using the orientation guide to install the pipe part and hence subsea foundation in a particular orientation compared to the seabed.

The method may comprise rotating the pipe part about its longitudinal axis to a particular orientation. The orientation guide may be used to indicate when the pipe part is at a particular orientation. This allows the orientation of any components connected to the pipe part, e.g. tools, equipment, casing(s) and/or drilling guides etc housed within the pipe of the pipe part and/or the subsea foundation after the pipe part has been connected thereto, to be adjusted.

The pipe part of the method of seventh aspect may be the pipe part of the fifth aspect described above and may have one or more or all of the above described features, including optional features.

The subsea foundation of the method of seventh aspect may be the subsea foundation of the sixth aspect described above and may have one or more or all of the above described features, including optional features.

Thus the present invention may provide a method of installing a pipe part according to the fifth aspect of the invention (including one, or more or all of the optional features), the method comprising providing the pipe and providing the orientation guide. The pipe part may be for use with and/or part of a subsea foundation system according to the sixth aspect (including one, or more or all of the optional features).

It has been realised that the pipe part for connection to the subsea foundation may be used as a pipe for housing equipment and/or tools etc. The pipe part may be used to house the equipment and/or tools before it is connected to the subsea foundation, e.g. housing the equipment and/or tools during transportation of the tools and equipment to the installation site. The pipe part may be referred to as a carrier pipe.

Such an arrangement of the pipe part acting as a carrier pipe for tools or equipment may be facilitated if the pipe comprises a plug and/or if the pipe part comprises an orientation guide. This for example may be because the plug (irrespective of whether it has a flat or shaped upper surface) may help to protect the internal tools or equipment during installation and the orientation guide may be used to ensure that the orientation of the internal (and possibly not visible) tools and equipment are installed in the correct orientation. If the pipe part comprises a plug and the plug has a shaped upper surface, the plug may be used to guide tools or equipment housed within the pipe part into a particular position.

When the pipe part is covered at the bottom end thereof by a plug, this may prevent soil entering the pipe and any internal conduits, e.g. drilling guide and/or casing as the pipe part is put into the formation. This may be particularly useful when the pipe part is forced into the seabed (rather than inserted into a preformed hole). This is because, if the pipe part is not plugged at the bottom end, as the pipe part is forced into the formation soil may enter the pipe. If the pipe part houses a deviated casing, drilling guide or any other asymmetric component, the soil entering the pipe of the pipe part may create a sideways force that makes vertical insertion of the pipe part and hence subsea foundation etc. into the seabed difficult.

However, it should be realised that the feature of the pipe part being used as a pipe for housing equipment and tools may be provided irrespective of whether the pipe part comprises a plug and/or orientation guide as described above.

Thus in another aspect the present invention may provide a pipe part for connection to a subsea foundation, wherein the pipe part comprises a pipe; and tools and/or equipment located within the pipe.

The tools and/or equipment located within the pipe may be or comprise one or more drilling guides, conduits, casings, and/or one or more instruments such as sensors etc. The tools and/or equipment may be housed within the pipe part during transportation.

Thus, in yet another aspect, the present invention may provide a method of transporting tools and/or equipment to an installation site, wherein tools and/or equipment are located within a pipe of pipe part for connection to a subsea foundation.

The tools and/or equipment located within the pipe may be, or comprise, a plurality of conduits, e.g. drilling guides and/or casings.

In an eighth aspect, the present invention may provide a pipe part for connection to a subsea foundation, wherein the pipe part comprises a pipe; and a plurality of conduits located within the pipe.

As explained above, it has been realised that the pipe part for connection to a subsea foundation can be used as a carrier pipe.

The conduits may be drilling guides. This means that it is a conduit that is used to direct drilling equipment as it drills and/or passes through the conduit.

The drilling guides may be casings and/or be arranged to have casings hung therefrom. When the conduit is a drilling guide that is a casing, this may mean that the conduit is designed to act as a guide for drilling equipment during drilling and also to provide the function of casing once the well drilling and/or installation is completed.

The conduits may be shaped to guide a drilling string in a desired direction for drilling. This may be straight and/or deviated.

The conduits, e.g. drilling guides and/or casings, and and/or any other tools or equipment may be housed entirely within the pipe of the pipe part. This may mean that none of the conduits (or other tools or equipment, if present) may protrude from the pipe part, at least whilst it is transported and/or before it is connected to the subsea foundation.

The conduits may be conduit extensions. This is because they be arranged to connect to respective upper conduits that are connected to the subsea foundation. The conduits may be casings that may be casing extensions.

The plurality of conduits may be located within the pipe of the pipe part before it is connected to the subsea foundation. Thus the pipe part may be a pipe part that is not yet connected to a subsea foundation.

The conduits may comprise one or more high pressure casing(s). When a conduit housed within the pipe of the pipe part is a casing for high pressure use, the conduit may be configured so that it can make a pressure tight connection with a part of the subsea foundation, such as an upper casing extension or the bottom of a high pressure wellhead. The conduit may comprise a pressure seal that is for sealing with a part, such as a upper casing part or wellhead, of the subsea foundation.

The pipe may additionally house other tools and/or equipment. These may be located alongside the plurality of conduits. Thus the pipe part may house a plurality of components, wherein the plurality of components comprises at least one conduit, e.g. a casing, and at least one other tool and/or equipment.

This means that the plurality of conduits (and any other internal components) may be put into and/or fixed within the pipe when the pipe part is not subsea, e.g. when the pipe part is onshore, such as in a workshop. The plurality of conduits (and any other internal components) may be put into and/or fixed within the pipe before the pipe part is transported to the installation site. Thus the conduits may be preinstalled in the pipe of the pipe part.

This may facilitate production of the pipe part and/or production of the overall subsea foundation system. For example, because the plurality of conduits (and/or other components) are put in the pipe when it is onshore and/or before it is connected to the subsea foundation the arrangement of the conduits (and/or other components) can be easily and precisely made. The arrangement of the conduits (and/or other components) within the pipe part after manufacture can also be easily -21 -seen and inspected, thereby allowing quality control and precise knowledge of where the internal components are located.

The pipe part may also provide a convenient means for transporting the conduits, e.g. drilling guides and/or casings, and/or other components to the installation site. This is because multiple components may be transported by transporting the pipe part. The pipe of the pipe part may act as a protection means, e.g. a housing, for the components, e.g. plurality of conduits located therein, during transportation.

The conduits may be fixed and supported within the pipe by one or more positioning pieces. These positioning pieces may act as form of centralizer (although the conduits may not be held in a central location) and may be used to hold the conduits in a fixed position within the pipe. This may be by welding or similar. The positioning pieces may be an alignment guide that is fixed to the outside of the conduit. The one or more alignment guides may be arranged so that when the conduit is inserted into the pipe of the pipe part, the alignment guides contact the inside of the pipe so as to align and hold the conduit in a particular position within the pipe of the pipe part. The one or more alignment guides may for example each be an annular piece that is located around the outside of the conduit. When for example the conduit is a deviated conduit, e.g. deviated drilling guide or deviated casing, the alignment guides towards the bottom may have an acentric hole. This may mean that the alignment guides are arranged to hold the conduit in an off-centre position. The alignment guides may be different along the length of the pipe part so as to align and hold the conduit in a gradually increasing off-centre position within the pipe part.

Additionally or alternatively the conduits (and any other equipment or tools housed in the pipe) may be fixed and/or supported within the pipe by a settable material such as cement or foam etc. This may provide a continuous fixing (at least over part of the length of the assembly) between the conduits and the pipe.

The pipe part may comprise two, three, four or more conduits located within the pipe. The plurality of conduits may be non-coaxial and/or not surround each other. In other words, the conduits, e.g. drilling guides and/or casings, may extend alongside each other.

One or more of the conduits, e.g. casings, may each be for connection (directly or indirectly) to a high pressure wellhead housing. The pipe part comprising a plurality of conduits may be for connection to a subsea foundation comprising a plurality of high pressure wellheads. The high pressure wellheads may be installed in and/or connected to the subsea foundation before or after the pipe part is connected to the subsea foundation. The conduits, e.g. casings, in the pipe part may be for connection to respective well casings that are attached to respective high pressure well head housings.

Thus a pipe part and corresponding subsea foundation to which it connects, may be used to house and/or support a plurality of subsea wells.

By providing a pipe part housing a plurality of conduits, e.g. casings, it may be possible to build a well system with a plurality of wells therein more quickly, easily and/or accurately compared to a well system with a plurality of wells built in a traditional way (without a separate pipe part that houses the plurality of conduits). One or more or all of the conduits located within the pipe may be a deviated casing, such as a J-tube. By deviated conduit it may be meant that the conduit is not concentric with a straight longitudinal axis along its length. This may mean that the central axis of one or more or all of the conduits may be not parallel, at least over part of its length, to the central axis of the pipe. When a deviated conduit is provided, it may in use act like a whipstock (i.e. a deviated drilling guide) when drilling occurs through the conduit.

The pipe of the pipe part may have a diameter that is not constant along its length. For example, the pipe may have a diameter at the bottom end (distal from the part of the pipe part that in use connects to a subsea foundation) that is greater than the diameter at its top end (proximal to the part of the pipe that in use connects to a subsea foundation). Thus the pipe part may have a larger diameter bottom portion and a smaller diameter top portion relative to each other. This may be to accommodate one or more deviated (i.e. bent, curved, slanted etc.) conduits and/or other components within the pipe part.

For example, the pipe part may have an upper portion with a narrower diameter (e.g. 30") and a lower portion with a larger diameter (e.g. 36"). Alternatively, the pipe part may be a constant diameter along its length.

The pipe part may comprise a plurality of deviated (i.e. bent, curved, slanted etc.) conduits. In this case, the deviated conduits may be positioned within the pipe part to deviate in directions away from each other. The amount of deviation of one or more conduits may depend on the precise design and the requirements. The pipe part for example may be used to provide a conduit, e.g. casing, with deviations of up to 5 degrees (such as about 3.7 degrees) or greater in the desired direction before any drilling is performed.

The deviated conduits may each have a portion at the top end (proximal to the end of the pipe part that in use will be connected to the subsea foundation) with a central axis that is parallel to the central axis of another conduit and/or the central axis of the pipe of the pipe part. The deviated conduits may each have a portion at the bottom end (distal to the end of the pipe part that in use will be connected to the subsea foundation) with a central axis that is non-parallel to the central axis of another conduit and/or the central axis of the pipe of the pipe part.

The pipe part may have a pipe part guide funnel at the top end. This may be used for guiding the pipe into attachment with the subsea foundation. Additionally or alternatively, one or more or all of the conduits may have a conduit guide funnel at the top end which is used for guiding the respective conduit of the pipe part into attachment with a respective part of the subsea foundation such as an upper well conduit part, or a wellhead.

In a ninth aspect the present invention may provide a subsea foundation system, wherein the subsea foundation system comprises: a subsea foundation; and a pipe part, wherein the subsea foundation system is arranged such that the pipe part can be connected to the subsea foundation, wherein the pipe part comprises a pipe; and a plurality of conduits located within the pipe.

The pipe part of the subsea foundation system of ninth aspect may be the pipe part of the eighth aspect described above and may have one or more or all of the above described features, including optional features.

Thus the present invention may provide a subsea foundation system, the subsea foundation system comprising a pipe part according to the eighth aspect of the invention (including one, or more or all of the optional features) The pipe part may be for connection to the subsea foundation. The pipe part may be connected to the subsea foundation. The pipe part may be directly connected to the subsea foundation. When the pipe part is connected to the subsea foundation it may protrude beyond the bottom of the subsea foundation. When the pipe part is connected to the subsea foundation the conduits may be located below the bottom of the subsea foundation (albeit it perhaps entirely inside the pipe of the pipe part).

This means that when the subsea foundation system is lowered towards the seabed the pipe part may contact and penetrate the seabed before the subsea foundation, and once the system is installed the conduits therein may be located below the bottom of the foundation.

This may mean that installation of a subsea foundation system comprising a plurality of wells may be completed at the installation site more quickly compared to a system without a pipe part with a plurality of conduits.

The pipe part may be connected to the subsea foundation when the subsea foundation, e.g. suction anchor, is subsea, but before it reaches the seabed.

The subsea foundation may comprise a plurality of upper conduits, e.g. upper casings, and/or wellheads (e.g. high pressure wellheads) to which the plurality of conduits located within the pipe of the pipe part are arranged to connect to when the pipe part is connected to the subsea foundation.

The system may comprise a single pipe part housing a plurality of conduits and a single subsea foundation.

In a tenth aspect the present invention may provide a method of connecting a pipe part to a subsea foundation, the method comprising: providing the subsea foundation; providing the pipe part, wherein the pipe part comprises a pipe, and a plurality of conduits located within the pipe; and connecting the pipe part to the subsea foundation.

The pipe part of the method of tenth aspect may be the pipe part of the eighth aspect described above and may have one or more or all of the above described features, including optional features.

The subsea foundation of the method of tenth aspect may be the subsea foundation of the ninth aspect described above and may have one or more or all of the above described features, including optional features.

Thus the present invention may provide a method of connecting a pipe part according to the eighth aspect of the invention (including one, or more or all of the optional features), the method comprising providing the pipe and providing the plurality of conduits located within the pipe of the pipe part. The pipe part may be for use with and/or part of a subsea foundation system according to the ninth aspect (including one, or more or all of the optional features).

The subsea foundation may comprise a plurality of upper conduits, e.g. upper casings, and/or wellheads (e.g. high pressure wellheads) to which the plurality of conduits located within the pipe of the pipe part are arranged to connect to when the pipe part is connected to the subsea foundation. The step of connecting the pipe part to the subsea foundation may comprise connecting each of the plurality of conduits of the pipe part to a respective upper conduit and/or wellhead of the subsea foundation.

It has been realised that because the subsea foundation system comprises a separate pipe part that may be manufactured and/or transported separately to the main subsea foundation, the pipe part may be a bespoke pipe part made for a particular project. Thus, a system may be designed and/or provided that comprises a subsea foundation and a bespoke pipe part.

In an eleventh aspect, the present invention may provide a method of designing a subsea foundation system, wherein the subsea foundation system comprises: a subsea foundation; and a pipe part, wherein the subsea foundation is arranged such that subsea the pipe part can be connected to the subsea foundation, the method comprising: obtaining details about the planned used of the subsea foundation system; and designing the pipe part based on the planned use.

The details about the planned use of the subsea foundation system may comprise one or more of, details of the installation site, the intended function of the subsea foundation system and/or details of the tools or equipment (such as the bottom hole assembly (BHA)) planned to be used with the subsea foundation (e.g. tools and equipment that in use with interact with and/or extend through the pipe part) etc. Details of the installation site may comprise details such as the geology of the installation site (e.g. whether the seabed is relatively hard or relatively soft) and/or any subsea formation that may interact, in use, with the subsea foundation system. This may affect aspects of the pipe part such as the material and dimensions of the pipe of the pipe part and the material of any components of the pipe part.

The intended function of the subsea foundation system may include whether the foundation is to be used as a well foundation or another type of foundation, such as a foundation for subsea systems such as a subsea substation. If the subsea foundation is to be used as a well foundation, the details about the planned use of the subsea foundation may comprise whether the subsea foundation system is to be an exploration well, a keeper well, a production well or relief well etc. This may affect the required material, dimensions of the pipe part and/or whether it is to be provided with any additional components.

The intended function of the subsea foundation system may include information about the tools and equipment planned to be used with the subsea foundation. The may affect whether the pipe art is provided with any additional features such as an internal plug with a shaped upper surface.

The method may comprise obtaining details about the subsea foundation. The method may comprise designing the pipe part based on the details of the subsea foundation. These details of the subsea foundation may comprise one or more of: type of foundation, dimensions of the foundation, materials of the foundation, mass of the foundation, details of the part of the foundation to which the pipe part in use will connect etc. The step of designing the pipe part may comprise selecting one or more of: the material of the pipe part (e.g. the material of the pipe (i.e. outer housing) of the pipe part), the dimensions of the pipe part (such as the length and /or diameter of the pipe part and/or the thickness of the pipe of the pipe part), and/or selecting whether any additional features are provided. The additional features may be components housed within or otherwise connected to or associated with the pipe part, such as equipment, tools, instruments, sensors, conduits, drilling guides, casings, plug, and/or orientation guide etc. The method may comprise determining whether an internal guiding function would be beneficial within the pipe part, and if so, providing a plug with a shaped upper surface to provide the desired guiding function. This may for example be a plug as disclosed above in relation to the first to fourth aspects of the invention.

Factors such as the tools and equipment that are planned to be used with the subsea foundation may affect whether the pipe part is designed with an orientation guide. For example, if components within the pipe of the pipe part are asymmetric the method may comprise designing the pipe part to have an orientation guide. The orientation guide may be an orientation guide as disclosed above in relation to the fifth to seventh aspects of the invention.

The additional features may comprise a plurality of conduits, e.g. drilling guides and/or casings, housed within the pipe of the pipe part as described above in relation to the eighth to tenth aspects of the invention.

The step of designing the pipe part may comprise providing a pipe part plan.

The method may comprise providing and/or manufacturing a pipe part according to the pipe part plan.

The pipe part may be referred to as a bespoke pipe part.

The subsea foundation may be a standard subsea foundation.

Thus in a twelfth aspect, the present invention may provide a subsea foundation system comprising a subsea foundation and a pipe part made according to the method of the eleventh aspect of the invention (including one or more or all fo the optional features).

The pipe part may comprise one or more of a plug, an orientation guide, a plurality of conduits, e.g. casings, and/or other internal components (e.g. with one or more or all of the features, including optional features as disclosed above in relation to the first to tenth aspects of the invention). Whether these additional features are provided may depend at least in part on the planned use of the subsea foundation system.

In a thirteenth aspect, the present invention may provide a kit of parts for providing a plurality of subsea foundation systems, the kit comprising a plurality of subsea foundations, and a plurality of pipe parts, wherein each pipe part is for connection to one of the subsea foundations to provide a subsea foundation system, wherein each subsea foundation is the same and wherein each pipe part is different.

For example, each subsea foundation may be a suction anchor foundation. Each subsea foundation system may be adapted to be suitable for a particular planned used by attaching a particular (e.g. bespoke designed) pipe part thereto.

This means that a large part of the subsea foundation system may be standardised yet adapted for a particular planned use by adapting the pipe part as required. This may provide a cheaper way of providing a subsea foundation system that is adapted for a particular planned use.

The present invention may provide the kit of parts of the thirteenth aspect wherein each subsea foundation system is designed according to the method of the eleventh aspect, optionally including one or more or all of the optional features.

Whilst the terms subsea and seabed etc. are used herein, it should be appreciated that this may mean under any large body of water such an ocean, lake etc and on any corresponding water bed and/or bed beneath that body of water.

As should be clear from the above, part or all of any of the aspects, examples, and/or embodiments described herein may be combined with one another in any suitable manner. Features that have been described in relation to one aspect, example, and/or embodiment herein, including but not limited to those features that have been described as being optional, may be implemented as part of one or more respective other aspects, examples and/or embodiments.

For example, a pipe part may be provided that comprises a plug with a shaped upper surface to act as a guide for tools or equipment located within or extending through the pipe, an orientation guide to facilitate the pipe part being installed in a particular orientation, and/or a plurality of conduits, e.g. casings, located within a pipe of the pipe part, optionally including one or more or all of the above described features. This pipe part may have been made, used, connected, designed etc according to any above disclosed methods, including one or more or all of the optional features.

Certain preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 shows a subsea foundation system comprising a pipe part with an internal plug; Figure 2 shows a second example pipe part with an internal plug; Figure 3 shows a third example pipe part with an internal plug; Figure 4 shows a fourth example pipe part with an internal plug; Figure 5 shows a pipe part with an internal plug that has been drilled through; and Figure 6 shows a subsea foundation system comprising a pipe part with internal equipment; Figure 7 shows the pipe part of figure 6; Figure 8 shows a subsea foundation system comprising a pipe part with an orientation guide; Figure 9 shows an enlargement of part of figure 8; and Figure 10 shows a pipe part housing a plurality of casings Figure 1 shows a subsea foundation system 1 comprising a suction anchor 2. The suction anchor 2 comprises an outer suction skirt 4, a top plate 6 and a centre pipe 8 that together bound an internal suction volume. The centre pipe 8 is connected indirectly in an airtight manner to the top plate 6.

Whilst the present invention is described herein in relation to a subsea foundation comprising a suction anchor, it should be appreciated that the invention may be applicable to other types of subsea foundations that may not comprise a suction anchor. Similarly the subsea foundation shown here is a foundation for a subsea well. However, the invention may be applicable to subsea foundations that are not for a subsea well.

The centre pipe 8 comprises an upper pipe portion 10 and a lower pipe portion 12 (which may also be referred to herein as a pipe part 12). Whilst the centre pipe 8 is shown as a two part pipe it should be appreciated that it may be formed from more than two pipe portions, or it may be provided by a single pipe part, i.e. just the lower pipe portion 12. The pipe portion 12 may be referred to as a lower pipe portion 12 because when it is connected to the subsea foundation 1 it protrudes beyond the bottom most surface of the subsea foundation 1.

The lower pipe portion 12 is connectable and disconnectable from the subsea foundation 1. In this example the lower pipe portion 12 is connectable and disconnectable from the upper pipe portion 10. The upper pipe portion 10 does not protrude beyond the bottom of the suction skirt 4 of the suction anchor 2. The lower pipe portion 12 however does protrude beyond the bottom of the suction anchor 2. Thus, when the subsea foundation 1 is sunk into the seabed the lower pipe portion 12 will reach and penetrate the seabed first. This may facilitate installation as a part (the lower pipe portion 12) can be penetrated into the seabed so as to hold the foundation 1 in an approximate location relative to the seabed whilst the orientation of the suction anchor 2 can be assessed and adjusted, if required.

The centre pipe 8 is fixed to the suction anchor 2 at an upper end to the top plate 6 and supported and centralised at the bottom end by stiffening plates 14.

The suction anchor 2 comprises I-beams 16 on the top plate 6. These I-beams 16 act to strengthen the top plate 6 and support the wellhead (shown in phantom).

The connection between the upper pipe portion 10 and the lower pipe portion 12 is overlapped by a pipe overlap section 18.

The pipe overlap section 18 may be fixed, such as welded, to the lower pipe portion 12.

The pipe overlap section 18 partially overlaps the lower pipe portion 12 so that a reliable connection can be made between the lower pipe portion 12 and the pipe overlap section 18.

The pipe overlap section 18 and hence the lower pipe portion 12 are connected to a pull-in arrangement 22. The pull-in arrangement 22 is used to connect the lower pipe portion 12 to the upper pipe portion 10. However, an equivalent pull in arrangement 22 could be used even if the lower pipe portion is connected directly to the top of the subsea foundation 1, rather than via the upper pipe portion 10.

The pull-in arrangement 22 comprises two pull-in lines 24 that extend through the suction anchor 2 through pull-in conduits 26. The pull-in conduits 26 at their upper end are connected to (and pass through) the suction anchor top plate 6 in a sealing manner. These conduits 26 allow the pull-in lines 24 to pass through the suction anchor internal volume without compromising the sealed nature of the internal volume. The pull-in lines 24 and pull-in line conduits 26 pass through the top plate 6 between two of the I-beams 16.

The pipe overlap section 18 is connected to pull-in line connection wings 28. The pull-in lines 24 each extend between a pull-in line connection wing 28 at one end to a pull-in line grip at the other end above the top plate 6 of the suction anchor.

These pull-in line grips each grip a pull-in line 24 and allow it to be pulled through and out of the suction anchor only. To achieve this the grips each comprise a one-way mechanism such as a ratchet and a lock to hold the pull-in line 24 once it has been pulled through the grip.

The pull-in line connection wings 28 allow the pull-in lines 24 to be radially spaced from the centre pipe 8.

The pull-in line conduits 26 are held in a fixed position relative to the centre pipe 8 by pull-in line conduit connectors 32. These connectors 32 connect the pull-in line conduits 26 to the centre pipe 8 and the internal stiffeners 14.

At the top end of the pipe overlap section 18 is a pipe connection guide 34 as shown most clearly in figures 7 and 10 (which show other lower pipe portions 12 with alternative features discussed further below). This pipe connection guide 34 is made up of a number of obliquely angled guide pieces that forms a circumferentially discontinuous guide funnel. When the lower pipe portion 12 is connected to the upper pipe portion 10 and the pipe overlap section 18 is overlapped over the upper pipe portion 10 the pipe connection guide 34 is used to guide the upper pipe portion into the pipe overlap section 18.

The pipe connection guide 34 is circumferentially discontinuous so that it can be located between the internal stiffeners 14 as shown in figure 1.

The lower pipe portion 12 is arranged to be made separately from the subsea foundation 1 and to be transported separately from the subsea foundation.

-31 -The subsea foundation and lower pipe portion 12 are arranged to that they can be connected together near the installation site and close in time to the installation procedure in which the lower pipe portion 12 and subsea foundation are located in and on the seabed.

The lower pipe portion 12 can be connected to the upper pipe portion 10 using the pull-in lines. This pull in may be performed by a winch for example.

When the lower pipe portion 12 is connected to the subsea foundation 1, the lower pipe portion 12 protrudes from the bottom of the suction skirt 4. The subsea foundation 1 may then be landed onto and sunk into the seabed.

The lower pipe portion 12 comprises an internal plug 13. The plug 13 is made of concrete or another material that may be drilled through.

The plug 13 has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the centre pipe 8 and hence through the lower pipe portion 12.

The upper surface of the plug 13 is a non-flat concave surface. In the example shown in figure 1 the plug 13 has a concave domed, approximately conical surface. This shaped upper surface can thus be used to help guide tools and equipment such as a drill string and/or casings towards the centre of the centre pipe 8 and lower pipe portion 12.

The plug 13 partially protrudes from the bottom of the lower pipe portion 12.

The upper surface of the plug is located within the lower pipe portion 12 but the lower surface of the plug is located outside and beneath the bottom of the lower pipe portion 12. In this case, when the subsea foundation 1 is sunk into the seabed the lower surface of the plug 13 will reach and penetrate the seabed first.

The lower surface of the plug 13 is also a non-flat surface and is shaped so it can act as a guide as the subsea foundation, and hence lower pipe portion 12, is sunk into the seabed. The lower surface of the plug 13 facilitates penetration of the lower pipe portion 12 into the seabed.

Figures 2, 3 and 4 show some alternative options for the shape of the upper surface of the plug 13, although the examples shown are not exhaustive and the upper surface of the plug 13 may be any shape that can be used to act as a guide for tools or equipment located within or extending through the lower pipe portion 12. Figure 2 shows an example plug 13 with an upper surface that has a concave frustoconical upper circumferentially outer surface that bounds an inner cylindrical recess. In this example the concave frustoconical upper circumferentially outer surface is arranged to, in use, guide tools and equipment, such as a drill string, towards the inner cylindrical recess, which is arranged, in use, to act as a pilot hole. This example plug 13 also has a lower protruding non-flat surface as described above, though the example upper surface shown could be provided with a plug 13 with a flat bottom surface.

Figure 3 shows an example plug 13 with an upper surface that has a concave conical upper surface. The apex of the cone is at the centre axis of the pipe portion 12. In this example the upper surface of the plug 13 can act to guide tools and equipment, such as a drill string or casing towards the centre of the pipe portion 12.

Figure 4 shows an example plug 13 with an upper surface that has a recess. In this example, the recess is a cylindrical recess at the centre of the plug and hence centre of the lower pipe portion 12. In this example the upper surface of the plug 13 can act as a pilot hole to help guide a drill string during drilling.

Although the example plugs 13 shown in figures 3 and 4 have flat bottoms, they could be provided with non-flat guiding bottoms that protrude from the pipe 12 as in the example shown in figure 2.

Figure 5 shows the retained part 13'of a plug that has been drilled through. This may for example be the plug 13 shown in figure 2. When the pipe portion 12 and hence plug 13 have been drilled through, some of the plug may remain within the pipe as shown in figure 5. This occurs when the outer diameter of the drill bit is smaller than the inner diameter of the pipe and hence the outer diameter of the drill bit is smaller than the outer diameter of the plug. The retained part 13' of the plug is the circumferentially outermost part of the plug. This retrained part of the plug may for example be 1 or 2 inches thick from the surface of the pipe portion 12. This retained part 13' of the plug left after drilling through the pipe and plug is also shaped so that in use it is configured to act as a guide for tools or equipment located within or extending through the pipe. This is because this part of the plug has a frustoconical upper surface, so as to guide tools or equipment such as casings towards the centre of the pipe portion 12 and hence towards the hole drilled through the plug 13.

The plug 13 can be formed and shaped in the pipe portion 12 when it is onshore and when the pipe portion is not connected to the subsea foundation 1. When the plug 13 is formed in a lower pipe portion 12 that is separate from the subsea foundation 1, it can be formed and shaped more easily and/or with greater precision.

The lower pipe portion 12 can alternatively or additionally house other tools, equipment and/or components such as a deviated casing 36 as shown in figures 6 and 7. Whilst lower pipe portion is shown and described with a deviated casing 36, this may be a conduit that is arranged so that in use it can act as a drilling guide and/or casing. However, the conduit may not be a casing and may be a conduit in which well casings are located when the well is built. The purpose of the conduit may be to act as a drilling guide. In either case, the conduit 36 may be for locating one or more casings therein, and/or hanging therefrom, as the well is installed/built.

This deviated casing 36 may be regarded as a casing extension as it is for connecting to (and thus extending) a casing in the subsea foundation.

In this arrangement the lower pipe portion 12 has an upper narrower section that has diameter that is smaller, e.g. 30", at the top and a lower wider section that has a diameter that is wider, e.g. 36", at the bottom.

Figure 6 shows the lower pipe portion 12 attached to the bottom of a subsea foundation that comprises a suction anchor and a wellhead assembly. The upper narrower section of the pipe portion 12 is substantially the same diameter as the centre pipe 8 of the suction anchor. The deviated casing 36 in the lower pipe portion 12 has the same diameter as the well casing 38 that hangs from the high pressure wellhead housing 40.

The deviated casing 36 may be fixed and supported within the lower pipe portion 12 by one or more positioning pieces 42 as shown most clearly in figure 7. These positioning pieces act as a form of alignment guide and are used to hold the casing 36 in a fixed position. In the example shown in figure 7 there are three positioning pieces. However any means for holding the casing 36 in place within the lower pipe portion 12 may be used.

The lower pipe portion 12 is for connection to the subsea foundation 1 and the internal casing 36 is for connection to the well casing 38 that is attached to the high pressure well head housing 40 in the subsea foundation 1.

The lower pipe portion 12 is arranged so that when it is connected to the subsea foundation 1 (e.g. pull-in by means of the pull-in arrangement), and specifically the centre pipe 8, the internal casing 36 is connected to the high pressure casing 38 of the subsea foundation 1.

As shown most clearly in figure 7, in addition to the housing having a guide funnel 34 at the top end, the internal casing 36 also has a guide funnel 44 at the upper end thereof. The casing guide funnel 44 is for guiding the internal casing 36 into attachment with the well casing 38 hanging from the high pressure wellhead housing 40.

Although not shown, when the casing 36 in the lower pipe portion 12 is for providing a high pressure casing, it may comprise a sealing arrangement that allows the connection made between the internal casing 36 and the upper casing 38 to be a pressure tight connection.

The internal casing 36 is fixed within the lower pipe portion 12 before the lower pipe portion 12 is transported to the installation site, e.g. this is done onshore in a workshop and before the lower pipe portion 12 is connected to the subsea foundation 1. Thus the casing 36 is preinstalled in the lower pipe portion 12.

The step of connecting the lower pipe portion 12 to the subsea foundation 1 may be before transportation to the installation site or at or near the installation site.

Before the lower pipe portion 12 is connected to the subsea foundation 1 the lower pipe portion 12 can be rotated about its longitudinal axis to a desired orientation. This allows the direction of deviated well casing 36 to be adjusted so that the direction of the start of a deviated well can be controlled.

In order to facilitate getting the lower pipe portion 12 to the correct orientation the system can comprise an orientation guide. This may be a visual, mechanical and/or electronic orientation guide.

Figures 8 and 9 show a system with a visual orientation guide 46. In this example the orientation guide 46 is a visual orientation guide. This is provided by having an external part of the lower pipe portion 12 visually different to the other parts of the lower pipe portion 12. In this example one of the pull-in connection wings 28 is a different colour (as illustrated in the black and white line drawing by the diagonal lines) to the rest of the lower pipe portion 12. Specifically one of the pull-in connection wings 28 is orange whilst the other pull-in connection wing and the rest of the lower pipe portion 12 is yellow.

The location and orientation of the components housed within the lower pipe portion 12 relative to the differently coloured pull-in connection wing 28 are known. This means that the differently coloured pull-in connection wing can be used during installation as a guide to ensure that the components housed within the lower pipe portion 12 are in the desired location and at the desired orientation.

The subsea foundation 1 also has a complementary visual orientation guide which in this example is a differently coloured lower portion of one of the pull-in conduits 26. The colour of the differently coloured lower portion of one of the pull-in conduits 26 is the same colour, e.g. orange, as the differently coloured pull-in connection wing 28 on the lower pipe portion. This means that when the pull-in arrangement is connected up, there is a visual indicator (in the form of the matching coloured pull-in conduit 26 and pull-in connection wing 28) to ensure that the correct pull-in line is connected to the correct pull-in connection wing 28 so that the lower pipe portion 12 is pulled into connection with the subsea foundation 1 in the correct orientation. Other complementary orientation guides may be used to ensure that the pipe part 12 is connected to the subsea foundation 1 in the correct orientation, e.g. an alternative visual guide and/or a mechanical orientation guide, and/or electronic orientation guide.

Further, when the lower pipe portion 12 is connected to the subsea foundation 1 the differently coloured pull-in connection wing 28 is located beyond the bottom of the foundation, i.e. in this case below the bottom of the suction skirt 4. This means that the differently coloured pull-in connection wing 28 can be used as a visual indicator to allow the lower pipe portion 12, and hence subsea foundation 1 to which it is connected, to be installed in the sea bed in a desired orientation.

The differently coloured pull-in connection wing 28 can be used to ascertain the orientation of the internal components housed within the lower pipe portion (because the relative positions of the internal components relative to the pull-in pipe connection wing are known). Thus the differently coloured pull-in connection wing 28 can also be used to ensure that the internal components housed within the lower pipe part 12 are installed in a desired orientation.

For example, when the internal components of the lower pipe portion 12 comprises one or more deviated casings, the orientation of the deviated casing(s) relative to the orientation guide (i.e. differently coloured pull-in connection wing 28) can be precisely known. As a result, the orientation guide can be used to allow the one or more deviated casings to be installed in a desired orientation.

Figure 10 illustrates that the lower pipe portion 12 may be used to house a plurality of casings 36. (Similarly to the arrangement of figure 6, although this ararnegment is shown and described as housing a plurality of casings 36, alternatively, these may be conduits that may or may not themselves be casings.

The conduits 36 may be drilling guides and/or casings. Irrespective of whether the conduits 36 are or are not casings, in use, e.g. after drilling therethrough the conduits 36 may be used to house and/or hang therefrom casings).

The arrangement of figure 10may be used for example when a single subsea foundation 1 is used to support a plurality of subsea wells.

The lower pipe portion 12 can be connected to a subsea foundation 1 comprising a corresponding plurality of upper casing portions which may each have a high pressure wellhead housing at their upper end. When the lower pipe portion 12 is connected to the subsea foundation 1, the casings 36 housed within the lower pipe portion 12 may connect to upper casings portions of the subsea foundation 1 to provide casings extending from the top of the subsea foundation 1 to the bottom of the lower pipe portion 12. This may help facilitate the installation of a subsea foundation 1 that provides support for a plurality of wells.

The two casings 36 shown in figure 10 are deviated casings. This means that the lower pipe portion 12 can be used to establish a kick off for the plurality of wells before any drilling is performed. This may facilitate and ease the installation of deviated wells, particularly those with requiring a relatively shallow horizontal portion of a well e.g. in the case of a small overburden.

Because the lower pipe part 12 is manufactured and/or transported separately from the subsea foundation 1, it has been realised that the lower pipe portion can be adapted as needed for a particular project. Thus a standard subsea foundation 1 can be provided with a bespoke lower pipe portion 12.

This may be achieved by obtaining details about the planned used of the subsea foundation system 1; and then designing the lower pipe portion 12 at least partly based on the planned use.

The details about the planned use of the subsea foundation system can include factors such as details of the installation site, the intended function of the subsea foundation system and/or details of the tools or equipment (such as the bottom hole assembly (BHA)) planned to be used with the subsea foundation (e.g. tools and equipment that in use with interact with and/or extend through the pipe part) etc. Details of the installation site can comprise details such as the geology of the installation site (e.g. whether the seabed is relatively hard or relatively soft) and/or any subsea formation (such as its location) that may interact, in use, with the subsea foundation system.

The aspects of the lower pipe portion 12 that are adjustable in design include the material and dimensions of the pipe of the pipe part and the material of any components of the pipe part. Also it can be decided whether any additional components are required and the form of these, e.g. what the additional components are and where they are located. For example, whether any deviated casings are required and the degree of deviation and orientation of the casings relative to an orientation guide, if provided.

The intended function of the subsea foundation system can include whether the foundation is to be used as a well foundation or another type of foundation, such as a foundation for subsea systems such as a subsea substation. If the subsea foundation is to be used as a well foundation, the details about the planned use of the subsea foundation can comprise whether the subsea foundation system is to be an exploration well, a keeper well, a production well or relief well etc. This may affect the required material, dimensions of the pipe part and/or whether it is to be provided with any additional components.

The intended function of the subsea foundation system can include information about the tools and equipment planned to be used with the subsea foundation. This can affect whether the pipe art is provided with any additional features such as an internal plug 13 with a shaped upper surface.

The method can also comprise obtaining details about the subsea foundation. The method can comprise designing the pipe part based on the details of the subsea foundation. These details of the subsea foundation can comprise one or more of: type of foundation, dimensions of the foundation, materials of the foundation, mass of the foundation, details of the part of the foundation to which the pipe part in use will connect etc. The step of designing the pipe part can comprise selecting one or more of: the material of the pipe part (e.g. the material of the pipe (i.e. outer housing) of the pipe part), the dimensions of the pipe part (such as the length and /or diameter of the pipe part and/or the thickness of the pipe of the pipe part), and/or selecting whether any additional features are provided. The additional features may be components housed within or otherwise connected to or associated with the pipe part, such as equipment, tools, instruments, sensors, conduits, drilling guides, casings, plug, and/or orientation guide etc. Factors such as the tools and equipment that are planned to be used with the subsea foundation could affect whether the pipe part is designed with an orientation guide. For example, if components within the pipe of the pipe part are asymmetric the method could comprise designing the pipe part to have an orientation guide as described above for example.

The designing of the lower pipe part can result in the provision of a pipe part plan.

A lower pipe part may then be provided and/or manufactured according to the pipe part plan.

A plurality of standard (e.g. the same) subsea foundations can be provided and then each subsea foundation can be adapted to be suitable for a particular planned used by attaching a particular (e.g. bespoke designed) pipe part thereto.

This means that a large part of the subsea foundation system may be standardised yet adapted for a particular planned use by adapting the separate lower pipe part as required. This can provide a cheaper way of providing a subsea foundation system that is adapted for a particular planned use.

The following clauses set out features of the inventions described herein (although not exhaustively) that may or may not be presently claimed and that may be claimed in future, including in foreign, divisional and/or continuation applications etc. 1. A pipe part for connecting to a subsea foundation, wherein the pipe part comprises a pipe and a plug, wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe.

2. The pipe part according to clause 1, wherein the shaped upper surface is a non-flat surface.

3. The pipe part according to clause 1 or 2. wherein the circumferentially outer upper surface of the plug is frustoconical.

4. The pipe part according to clause 1, 2 or 3, wherein the shaped upper surface of the plug comprises a recessed portion.

5. The pipe part according to clause 4, wherein the recessed portion is configured to, in use, act as a pilot hole to guide drilling.

6. The pipe part according to any preceding clause, wherein the shaped upper surface comprises a concave frustoconical upper circumferentially outer surface that bounds an inner cylindrical recess.

7. The pipe part according to any preceding clause, wherein the plug is a concrete plug.

8. The pipe part according to any preceding clause, wherein the upper surface of the plug is located within the pipe.

9. The pipe part according to any preceding clause, wherein the plug protrudes from one end of the pipe.

10. The pipe part according to any preceding clause, wherein lower surface of the plug is shaped such that it is configured, in use, to act as a guide.

11. The pipe part according to any preceding clause, wherein the lower surface of the plug is a non-flat surface.

12. A subsea foundation system, the subsea foundation system comprising: a subsea foundation; and a pipe part, wherein the pipe part comprises a pipe and a plug, and wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or through the pipe.

13. The subsea foundation system according to clause 12, wherein the subsea foundation system comprises an upper pipe portion connected to the subsea foundation, wherein the pipe part, is for connection to or connected to the upper pipe portion.

14. The subsea foundation system according to any of clauses 12 or 13, wherein the subsea foundation is a suction anchor.

15. The subsea foundation system according to any of clauses 12, 13 or 14, wherein the subsea foundation is a foundation for a subsea well and wherein the pipe part provides at least part of a pipe for the subsea well.

16. The subsea foundation system according to any of clauses 12 to 15, wherein the pipe part is the pipe part according to any of clauses 1 to 11.

17. A method of providing a pipe part for a subsea foundation system, wherein the pipe part comprises a pipe and a plug, the method comprising: providing the pipe; and providing the plug within the pipe, wherein the plug has a shaped upper surface such that, in use, the plug is configured to act as a guide for tools or equipment located within or extending through the pipe.

18. A method according to clause 17, wherein the plug is provided within the pipe when the pipe part is onshore.

19. A method according to clause17 or 18, wherein the pipe part is the pipe part according to any of clauses 1 to 11. 20 20. A method of guiding a tool or equipment in a pipe part of a subsea foundation system, the method comprising: providing the pipe part, wherein the pipe part comprises a pipe and a plug, and wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe; and inserting the tool or equipment into the pipe and using the upper surface of the internal plug to at least partly guide the location of the tool or equipment.

21. A method according to clause 20, wherein the method comprises drilling through the plug.

22. A method according to clause 21, wherein when the plug has been drilled through, at least some of the plug remains within the pipe as a retained part of the plug and wherein the retained part of the plug is shaped so that in use it is -41 -configured to act as a guide for tools or equipment located within or extending through the pipe.

23. A method according to any of clauses 20 to 22, wherein the step of providing the pipe part is the method of any of clauses 17 to 20.

24. A pipe part for connecting to a subsea foundation, wherein the pipe part comprises an orientation guide to facilitate the pipe part being installed in a particular orientation.

25. The pipe part according to clause 24, wherein the orientation guide comprises an external orientation guide.

26. The pipe part according to clauses 24 or 25, wherein the orientation guide comprises a visual orientation guide that can be seen during installation of the pipe part.

27. The pipe part according to clauses 24, 25 or 26, wherein the orientation guide is a differently coloured part compared to the rest of the pipe part.

28. The pipe part according to clause 27, wherein the orientation guide is orange.

29. The pipe part according to any of clauses 24 to 28, wherein the pipe part is the pipe part according to any of clauses 1 to 11.

30. A subsea foundation system comprising: a pipe part for connecting to a subsea foundation; and a subsea foundation, wherein the pipe part comprises an orientation guide to facilitate the pipe part being installed in a particular orientation.

31. The subsea foundation system of clause 30, wherein the orientation guide is configured to facilitate the pipe part being connected to the subsea foundation in a particular orientation.

32. The subsea foundation system of clauses 30 or 31, wherein the orientation guide is configured to facilitate the pipe part being installed in a particular orientation relative to the seabed.

33. The subsea foundation system of any of clauses 30, 31 or 32, wherein when the pipe part is connected to the subsea foundation the orientation guide is located beyond the bottom of the subsea foundation and/or visible from a location external of the subsea foundation.

34. The subsea foundation system of any of clauses 30 to 33, wherein the orientation guide of the pipe part is a first orientation guide, and wherein the subsea foundation comprises a second orientation guide.

35. The subsea foundation system of clause 34, wherein the first orientation guide and the second orientation guide are configured so that the pipe part can only be connected to the subsea foundation in a particular orientation.

36. The subsea foundation system of any of clauses 30 to 35, wherein the subsea foundation system comprises a pull-in arrangement for connecting the pipe part to the subsea foundation, and wherein the orientation guide is part of the pull-in arrangement.

37. The subsea foundation of any of clauses 30 to 36, wherein the pipe part is the pipe part of any of clauses 24 to 29.

38. A method of installing a pipe part, wherein the pipe comprises an orientation guide to facilitate the pipe being installed in a particular orientation, the method comprising: providing the pipe part; providing a subsea foundation; connecting the pipe part to the subsea foundation; and using the orientation guide to install the pipe part in the particular orientation.

39. The method of clause 38, wherein the step of using the orientation guide to install the pipe part in the particular orientation comprises using the orientation guide to connect the pipe part to the subsea foundation in a particular orientation.

40. The method of clause 38 or 39, wherein the step of using the orientation guide to install the pipe part in the particular orientation comprises using the orientation guide to facilitate installing the pipe part and/or subsea foundation in a particular orientation relative to the seabed.

41. The method of clause 38, 39 or 40, wherein the orientation guide is used to both connect the pipe part to the subsea foundation in a particular orientation and install the pipe part and hence subsea foundation in a particular orientation on the seabed.

42. The method of any of clauses 38 to 41, wherein the pipe part is the pipe part according to any of clauses 1 to 11, or 24 to 29 and/or the subsea foundation is the subsea foundation according to any of clauses 12 to 16, or 30 to 37.

43. A pipe part for connection to a subsea foundation, wherein the pipe part comprises a pipe; and a plurality of conduits located within the pipe.

44. The pipe part according to clause 43, wherein the conduits are housed entirely within the pipe of the pipe part.

45. The pipe part according to clause 43 or 44, wherein the plurality of conduits are be located within the pipe of the pipe part before the pipe part is connected to the subsea foundation.

46. The pipe part according to clause 43, 44 or 45, wherein one or more or all of the conduits are arranged to, in use, each act as a drilling guide and/or a casing.

47. The pipe part according to any of clauses 43 to 46, wherein the conduits comprise one or more high pressure casings.

48. The pipe part according to any of clauses 43 to 47, wherein the conduits are each for connection to a high pressure wellhead housing.

49. The pipe part according to any of clauses 43 to 48, wherein other tools and/or equipment are located within the pipe.

50. The pipe part according to any of clauses 43 to 49, wherein the conduits comprise one or more deviated conduits.

51. The pipe part according to any of clauses 43 to 50, wherein the conduits comprise a plurality of deviated conduits, and wherein the deviated conduits are located within the pipe such that the deviated conduits deviate in directions away from each other.

52. The pipe part according to any of clauses 43 to 51, wherein the pipe has a diameter at one end that is greater than the diameter at the other end.

53. The pipe part according to any of clauses 43 to 52, wherein the pipe part comprises the pipe part according to any of clauses 1 to 11 or 24 to 29.

54. A subsea foundation system comprising: a subsea foundation; and a pipe part, wherein the pipe part and the subsea foundation system are arranged such that the pipe part can be connected to the subsea foundation, wherein the pipe part comprises a pipe; and a plurality of conduits located within the pipe.

55. The subsea foundation system according to clause 54, wherein the subsea foundation comprises a plurality of upper conduits and/or wellheads to which the plurality of conduits located within the pipe of the pipe part are arranged to connect to when the pipe part is connected to the subsea foundation.

56. The subsea foundation system according to clause 54 or 55, wherein the subsea foundation is for supporting a plurality of subsea wells.

57. The subsea foundation system according to clause 54, 55 or 56, wherein the pipe part is the pipe part according to any of clauses 1 to 11, 24 to 29, or 43 to 53.

58. A method of connecting a pipe part to a subsea foundation, the method comprising: providing the subsea foundation; providing the pipe part, wherein the pipe part comprises a pipe, and a plurality of conduits located within the pipe; and connecting the pipe part to the subsea foundation to form a subsea foundation system.

59. The method according to clause 58, wherein the plurality of conduits are located within the pipe before the pipe part is subsea; before the pipe part is transported to the installation site; and/or before the pipe part is connected to the subsea foundation.

60. The method according to clause 58 or 59, wherein the subsea foundation comprises a plurality of upper conduits and/or wellheads to which the plurality of conduits located within the pipe of the pipe part are arranged to connect to when the pipe part is connected to the subsea foundation, and wherein the step of connecting the pipe part to the subsea foundation comprises connecting each of the plurality of conduits of the pipe part to a respective upper conduit and/or wellhead of the subsea foundation.

61. The method according to any of clauses 58, 59 or 60, wherein the pipe part is the pipe part according to any of clauses 1 to 11, 24 to 29, or 43 to 53 and/or the subsea foundation is the subsea foundation according to any of clauses 12 to 16, 30 to 37, or 54 to 57.

62. A method of designing a subsea foundation system, wherein the subsea foundation system comprises: a subsea foundation; and a pipe part for connecting to the subsea foundation to provide the subsea foundation system, the method comprising: obtaining details about the planned used of the subsea foundation system; and designing the pipe part based on the planned use.

63. The method according to clause 62, wherein the details about the planned use of the subsea foundation system comprise one or more of details of the planned installation site, the intended function of the subsea foundation system; and/or details of tools or equipment planned to be used with the subsea foundation.

64. The method according to clause 63, wherein the intended function of the subsea foundation system includes whether the foundation is to be used as a well foundation or another type of foundation, 65. The method according to clause 64, wherein if the subsea foundation is to be used as a well foundation, comprise whether the subsea foundation system is to be an exploration well, a keeper well, a production well or relief well.

66. The method according to any of clauses 62 to 65, wherein the method comprises obtaining details about the subsea foundation, and designing the pipe part based on the details about the subsea foundation, 67. The method according to clause 66, wherein the details about the subsea foundation comprise one or more of: type of foundation, dimensions of the foundation, materials of the foundation, mass of the foundation, details of the part of the foundation to which the pipe part in use will connect.

68. The method according to any of clauses 62 to 67, wherein the step of designing the pipe part comprises selecting one or more of: the material of the pipe part, the dimensions of the pipe part, and/or whether any additional features are provided.

69. The method according to clause 68, wherein the additional features are components housed within or otherwise associated with the pipe part, and include one or more of equipment, tools, instrument, sensor, conduit, casing, drilling guide, plug, and/or orientation guide.

70. The method according to any of clauses 62 to 69, wherein the step of designing the pipe part comprises providing a pipe part plan.

71. The method according to any of clauses 62 to 70, wherein the method comprises manufacturing and/or providing the pipe part.

72. A subsea foundation system comprising: a subsea foundation; and a pipe part, wherein the subsea foundation system is designed according to the method of any of clauses 62 to 71.

73. The subsea foundation system according to clause 72, wherein the pipe part is the pipe part according to any of clauses 1 to 11, 24 to 29, or 43 to 53 and/or the subsea foundation is the subsea foundation according to any of clauses 12 to 16, 30 to 37, or 54 to 57.

74. A kit of parts for providing a plurality of subsea foundation systems, the kit of parts comprising a plurality of subsea foundations, and a plurality of pipe parts, wherein each pipe part is for connection to one of the subsea foundations to provide a subsea foundation system, wherein each subsea foundation is the same as the other subsea foundations and wherein each pipe part is different from the other pipe parts.

75. The kit of parts of clause 74, wherein each subsea foundation system is designed according to the method of any of clauses 62 to 72.

76. The kit of parts of clause 75, wherein the pipe part is the pipe part according to any of clauses 1 to 11, 24 to 29, or 43 to 53 and/or the subsea foundation is the subsea foundation according to any of clauses 12 to 16, 30 to 37, or 54 to 57.

Claims

CLAIMS: 1. A pipe part for connecting to a subsea foundation, wherein the pipe part comprises a pipe and a plug, wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe.
2. The pipe part according to claim 1, wherein the shaped upper surface is a non-flat surface.
3. The pipe part according to claim 1 or 2, wherein the circumferentially outer upper surface of the plug is frustoconical.
4. The pipe part according to claim 1, 2 or 3, wherein the shaped upper surface of the plug comprises a recessed portion.
5. The pipe part according to claim 4, wherein the recessed portion is configured to, in use, act as a pilot hole to guide drilling.
6. The pipe part according to any preceding claim, wherein the shaped upper surface comprises a concave frustoconical upper circumferentially outer surface that bounds an inner cylindrical recess.
7. The pipe part according to any preceding claim, wherein the upper surface of the plug is located within the pipe.
8. The pipe part according to any preceding claim, wherein the plug protrudes from one end of the pipe.
9. The pipe part according to any preceding claim, wherein lower surface of the plug is shaped such that it is configured, in use, to act as a guide.
10. A subsea foundation system, the subsea foundation system comprising: a subsea foundation; and a pipe part, wherein the pipe part comprises a pipe and a plug, and wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or through the pipe.
11. The subsea foundation system according to claim 10, wherein the subsea foundation system comprises an upper pipe portion connected to the subsea foundation, wherein the pipe part, is for connection to or connected to the upper pipe portion.
12. The subsea foundation system according to any of claims 10 or 11, wherein the subsea foundation is a suction anchor.
13. The subsea foundation system according to any of claims 10, 11 or 12, wherein the subsea foundation is a foundation for a subsea well and wherein the pipe part provides at least part of a pipe for the subsea well.
14. A method of providing a pipe part for a subsea foundation system, wherein the pipe part comprises a pipe and a plug, the method comprising: providing the pipe; and providing the plug within the pipe, wherein the plug has a shaped upper surface such that, in use, the plug is configured to act as a guide for tools or equipment located within or extending through the pipe.
15. A method according to claim 14, wherein the plug is provided within the pipe when the pipe part is onshore.
16. A method of guiding a tool or equipment in a pipe part of a subsea foundation system, the method comprising: providing the pipe part, wherein the pipe part comprises a pipe and a plug, and wherein the plug has a shaped upper surface such that in use the plug is configured to act as a guide for tools or equipment located within or extending through the pipe; and inserting the tool or equipment into the pipe and using the upper surface of the internal plug to at least partly guide the location of the tool or equipment.
-51 - 17. A method according to claim 16, wherein the method comprises drilling through the plug.
18. A method according to claim 17, wherein when the plug has been drilled through, at least some of the plug remains within the pipe as a retained part of the plug and wherein the retained part of the plug is shaped so that in use it is configured to act as a guide for tools or equipment located within or extending through the pipe.
19. A pipe part for connecting to a subsea foundation, wherein the pipe part comprises an orientation guide to facilitate the pipe part being installed in a particular orientation.
20. The pipe part according to claim 19, wherein the orientation guide is a differently coloured part compared to the rest of the pipe part.
21. A subsea foundation system comprising: a pipe part for connecting to a subsea foundation; and a subsea foundation, wherein the pipe part comprises an orientation guide to facilitate the pipe part being installed in a particular orientation.
22. The subsea foundation system of claim 21, wherein the orientation guide is configured to facilitate the pipe part being connected to the subsea foundation in a particular orientation.
23. The subsea foundation system of claim 21 or 22, wherein the orientation guide is configured to facilitate the pipe part being installed in a particular orientation relative to the seabed.
24. The subsea foundation system of any of claims 21 to 23, wherein the orientation guide of the pipe part is a first orientation guide, and wherein the subsea foundation comprises a second orientation guide, wherein the first orientation guide and the second orientation guide are configured so that the pipe part can only be connected to the subsea foundation in a particular orientation.
25. The subsea foundation system of any of claims 21 to 24, wherein the subsea foundation system comprises a pull-in arrangement for connecting the pipe part to the subsea foundation, and wherein the orientation guide is part of the pull-in arrangement.
26. A method of installing a pipe part, wherein the pipe comprises an orientation guide to facilitate the pipe being installed in a particular orientation, the method comprising: providing the pipe part; providing a subsea foundation; connecting the pipe part to the subsea foundation; and using the orientation guide to install the pipe part in the particular orientation.
27. The method of claim 26, wherein the orientation guide is used to both connect the pipe part to the subsea foundation in a particular orientation and install the pipe part and hence subsea foundation in a particular orientation on the seabed.
28. A pipe part for connection to a subsea foundation, wherein the pipe part comprises a pipe; and a plurality of conduits located within the pipe.
29. The pipe part according to claim 28, wherein the conduits are housed entirely within the pipe of the pipe part.
30. The pipe part according to claim 28 or 29, wherein the plurality of conduits are be located within the pipe of the pipe part before the pipe part is connected to the subsea foundation.
31. The pipe part according to any of claims 28 to 30, wherein the conduits comprise one or more high pressure casings.
32. The pipe part according to any of claims 28 to 31, wherein other tools and/or equipment are located within the pipe.
33. The pipe part according to any of claims 28 to 32, wherein the conduits comprise a plurality of deviated conduits, and wherein the deviated conduits are located within the pipe such that the deviated conduits deviate in directions away from each other.
34. A subsea foundation system comprising: a subsea foundation; and a pipe part, wherein the pipe part and the subsea foundation system are arranged such that the pipe part can be connected to the subsea foundation, wherein the pipe part comprises a pipe; and a plurality of conduits located within the pipe.
35. The subsea foundation system according to claim 34, wherein the subsea foundation comprises a plurality of upper conduits and/or wellheads to which the plurality of conduits located within the pipe of the pipe part are arranged to conned to when the pipe part is connected to the subsea foundation.
36. The subsea foundation system according to claim 34 or 35, wherein the subsea foundation is for supporting a plurality of subsea wells.
37. A method of connecting a pipe part to a subsea foundation, the method comprising: providing the subsea foundation; providing the pipe part, wherein the pipe part comprises a pipe, and a plurality of conduits located within the pipe; and connecting the pipe part to the subsea foundation to form a subsea foundation system.
38. The method according to claim 37, wherein the plurality of conduits are located within the pipe before the pipe part is subsea; before the pipe part is transported to the installation site; and/or before the pipe part is connected to the subsea foundation.
39. A method of designing a subsea foundation system, wherein the subsea foundation system comprises: a subsea foundation; and a pipe part for connecting to the subsea foundation to provide the subsea foundation system, the method comprising: obtaining details about the planned used of the subsea foundation system; and designing the pipe part based on the planned use.
40. The method according to claim 39, wherein the details about the planned use of the subsea foundation system comprise one or more of: details of the planned installation site, the intended function of the subsea foundation system; and/or details of tools or equipment planned to be used with the subsea foundation.
41. The method according to claim 40, wherein the intended function of the subsea foundation system includes whether the foundation is to be used as a well foundation or another type of foundation,
42. The method according to any of claims 39 to 41, wherein the method comprises obtaining details about the subsea foundation, and designing the pipe part based on the details about the subsea foundation, wherein the details about the subsea foundation comprise one or more of: type of foundation, dimensions of the foundation, materials of the foundation, mass of the foundation, details of the part of the foundation to which the pipe part in use will connect.
43. The method according to any of claims 40, 41 or 42, wherein the step of designing the pipe part comprises selecting one or more of: the material of the pipe part, the dimensions of the pipe part, and/or whether any additional features are provided, wherein the additional features are components housed within or otherwise associated with the pipe part, and include one or more of equipment, tools, instrument, sensor, casing, conduit, drilling guide plug, and/or orientation guide.
44. A subsea foundation system comprising: a subsea foundation; and a pipe part, wherein the subsea foundation system is designed according to the method of any of claims 40 to 43.
45. A kit of parts for providing a plurality of subsea foundation systems, the kit of parts comprising a plurality of subsea foundations, and a plurality of pipe parts, wherein each pipe part is for connection to one of the subsea foundations to provide a subsea foundation system, wherein each subsea foundation is the same as the other subsea foundations and wherein each pipe part is different from the other pipe parts.