NO20221225A1

NO20221225A1 - An apparatus for performing operations inside a cylindrical body.

Info

Publication number: NO20221225A1
Application number: NO20221225A
Authority: NO
Inventors: Bjarne Langeteig
Original assignee: Pipesnake As
Priority date: 2022-11-15
Filing date: 2022-11-15
Publication date: 2024-05-16
Also published as: NO348358B1

Description

AN APPARATUS FOR PERFORMING OPERATIONS INSIDE A

CYLINDRICAL BODY

TECHNICAL FIELD OF THE INVENTION

The invention relates to an apparatus for performing operations inside a cylindrical body and a method for deploying an apparatus. More specifically, the invention relates to fluid driven tractor apparatus, in areas of use including hoses, bounded and un-bounded flexible risers, pipelines, wells etc.

BACKGROUND

Current day technologies employ several different mechanisms for performing operations inside a cylindrical body such as, oil and gas wells, water injection and production pipelines. One such example is a pipeline tractor. The pipeline tractors employ different mechanisms for propulsion or movements of the tractors inside a cylindrical or an elongated body. Some use the force of the fluid flowing in the pipeline for propulsion Others use wheels or belts for moving along the pipeline.

In the following description, the apparatus for performing operations inside a cylindrical body is referred to as apparatus, tractor apparatus and tractor interchangeably and without any intention to differentiate between the terms.

In an example, pipeline tractors may be employed in oil and gas wells for inspection and maintenance of pipelines or hoses. These tractors are designed and built specifically for offshore use and for transporting equipment through wells. The tractors may not be suitable for other applications such as maintenance of water pipes etc. Further, tractors in market for oil and gas wells are designed to operate in horizontal section of wellbore. Often these tractors run through the vertical section of the oil well or to an operating area by gravity. In some cases, to enable easy operations in vertical section, the tractors are helped by push from surface using injector on surface, however these are less effective, when the distance from surface (outside of pressure area) to tractor is greater.

In another example, some non-offshore tractors are designed with lesser operating pressure, less pull force and use of other chemicals in combination for operating the tractors.

Several varieties of downhole tractors based on different technologies are in use in the market. Majority of these tractors are driven by electronic or fluid power, and with use of wheels, belts or piston for moving along the pipe.

There are several shortcomings related to such tractors, for example, the tractors have low traction force mainly due to the small size of the wheels against the walls of the cylindrical body. In many cases the tractors in market provide acceptable pull force to enter to the bottom of the cylindrical body. However, in some cases the friction may be too high to use traditional tractors due to: Long horizontal section, inclining horizontal section, doglegs, weight of supporting equipment , pressure, push and pull requirements for downhole tools or combinations of these.

Traditional tractor designs also require long lengths of lubricators to deploy tractor into pressure. The tractor length often limits the tools that can be transported into the cylindrical body.

This also means they can carry very limited workloads and may not be able to drag heavy tools, parts or umbilicals/cables along the tractor within the cylindrical body.

NO178276B describes a pipe tractor arranged to move within canals and pipes wherein, the end portions of the tractor is mounted and equipped with spring loaded arms to which crosswise wheels are mounted, and the wheels abut the inner surface of the pipe, so that side force affecting the wheels provides for propulsion of the vehicle when the end portions are rotating. The end portions rotate in opposite directions related to each other, and one of the ends acts as counter torque for the other end, and vice versa.

WO2009093915A1 describes another internal pipe vehicle for travelling inside a pipeline and provides a tractor which can travel faster and at higher accuracy and pass sharp bends or T bends.

However, a great disadvantage associated with these tractors is that they are relatively smaller in size and therefore do not provide the required pressure in the system for operation. Such systems may thus employ pressure boosters and lead to a much more heavy and complex system with several components. This in turn, makes these systems slow in response times.

The problems become more pronounced when operations are to be carried out with high level of responsiveness or control precision in systems for example, in oil and gas wells, bores, subsea installations and hoses.

WO2022129328A1 is a previous publication from the inventor and describes an apparatus for operation inside a cylindrical body that is equipped with eccentric wheels which are tilted at an angle, thus when the wheels are rotated they will undergo a helical movement and thereby screw through or achieve propulsion inside the cylindrical body.

The aforementioned tractor systems do not describe the possibility to accommodate umbilicals or cables on them. As a result, electrical connections or power supply, fluid supply to the motor and so on must be provided additionally to the tractor.

In addition, the existing tractor systems are not suitable for operation both inside open hole and cased hole.

Further, the existing tractor systems employ different mechanism for driving the tractors such as combination of cables and or/and chemicals to drive tractors that employ acid, scavengers etc. for operations of the tractor.

Such tractors are not successful in operations in pressurized environments such as operations in a hose, while simultaneously handling friction and pressure from the environment in the hose and the cables employed.

Hence, there is a need for providing the tractors operable in pressurized working environments and provided with integrated umbilicals or cables that can serve various needs of the tractor while eliminating bulky components on the tractor.

Another object is to provide robust tractor system that can perform operations inside open hole or cased hole.

A further object is to measure the pull, length and other forces acting on the tractor system when deployed in different areas such as hose, bounded and un-bounded flexible risers, pipelines, wells etc.

The object of the invention is achieved by means of the patent claims.

SUMMARY

In the following description, the term "cylindrical body" is used to describe any kind of body having an elongated extending opening, such as a pipeline, duct, channel, tube, drilled well with or without casing. Examples are flexible risers, umbilicals, oil or gas wells during or after drilling, oil or gas production pipelines, water pipes, waste pipes, process plant pipelines, geothermal wells, etc.

An apparatus for performing operations inside a cylindrical body comprises in one embodiment a fluid supply means extending from a rear end of the apparatus for providing fluid to the apparatus, at least one pressure diversion unit in fluid communication with the fluid supply means, a front drive module (25) and a rear drive module in fluid communication with the pressure diversion unit , and a fluid motor in fluid communication with the front drive module and rear drive module, the motor being controlled by a control unit.

The fluid supply means for providing fluid to the apparatus can be at least one of: an umbilical, a hose, steel pipe (threaded or non-threaded), composite.

The apparatus may comprise a cavity/channel for supply of hydraulic or pneumatic fluid, wherein the fluid drives the front drive module and rear drive module for propulsion of the apparatus inside a cylindrical body.

In one embodiment the hydraulic or pneumatic fluid is in communication with a hydraulic or pneumatic cylinder employed in the front drive module and the rear drive module of the apparatus.

The front and rear drive modules may comprise a plurality of wheels. The front drive module and the rear drive module may comprise eccentric drives with a tilting mechanism, wherein the tilting mechanism tilts the plurality of wheels for propulsion of the apparatus in the cylindrical body.

The wheels of the front drive module rotate in one embodiment in a counter rotate direction with respect to the wheels of the rear drive module.

In some embodiments, the motor is placed between the front drive module and the rear drive module and rotates such that the rotation of the motor with respect to its housing and rotor achieves the same RPM in opposite direction due to friction from the front and rear drive module, thus preventing turning of the whole apparatus during operation inside the cylindrical body.

The motor may be placed either at the front of or back of the front drive module and the rear drive module. The front drive module and the rear drive module may be connected through a shaft to each other.

The apparatus may further comprise a central shaft extending along the inner region of the apparatus and supporting different modules of the apparatus.

The apparatus may further comprise a front pressure diversion unit connected to control pressure of the front drive module and a rear pressure diversion unit connected to control pressure of the rear drive module.

The front and rear pressure diversion units can distribute the hydraulic or pneumatic fluid to the front and rear drive modules to activate the wheels of the drive modules.

The apparatus may further comprise an interface for providing a plurality of addons and scaling components.

The add-ons can include at least one of: additional drive modules, joints, gears, weaklinks, burst discs, flow activated tools, memory tools, time activated tools and emergency tools or fail safe mechanisms.

The cylindrical body is for example one of: a pipeline, flowline, umbilicals, hose, flexible risers, bounded and un-bounded.

The apparatus may further comprise a sensor module with sensors for measuring temperature, fluid flow, torque, pressure, humidity.

The is in some embodiments configured to be employed from the land surface using lubricators including at least one of: pipe, hose, bends and by means of the push force of the apparatus.

The apparatus can be configured to guide the fluid supply means into a lubricator through one of: gooseneck, sheave wheels, roller guides.

BRIEF DESCRIPTION OF FIGURES

Figure 1 is a prior art illustration of a tractor apparatus for movement in a pipeline.

Figure 2 is an example of a tractor apparatus according to the invention.

Figure 3 illustrates an exploded view of the tractor apparatus of figure 2.

Figure 4 illustrates schematically hydraulic system of the tractor apparatus for propulsion and operations inside a cylindrical body.

Figure 5 illustrates the operation of the tractor apparatus inside a cylindrical body.

Figure 6a and 6b illustrate sectional view of hydraulic fluid flow line of the tractor apparatus. Figure 7a and 7b illustrate a sectional view of the front and the rear stator shafts of the tractor apparatus according to the invention.

Figure 8 illustrates add-ons to the tractor apparatus, according to an embodiment of the invention.

DETAILED DESCRIPTION

The drawings herein are appended to facilitate the understanding of the invention. The drawings show embodiments of the invention and do not intend to limit the invention. The drawings will now be described by way of example only, where:

Figure 1 illustrates a prior art tractor apparatus for movement in a pipeline. As shown in WO2022129328A1, the tractor apparatus 10 comprises a central shaft 11 extending along the axis of the tractor. A front 13 and rear drive module 14 are provided on the tractor, wherein the drive modules each further comprises a plurality of wheels 12 arranged to rotate around the shaft 11 and the center axis of the tractor. The position of the wheels 12 with respect to the shaft 11 can be changed by means of eccentric drives which are configured to move the wheels in a radial direction relative to the shaft to achieve an eccentric state with respect to the shaft 11 and the center axis of the tractor.

The wheels 12 are further connected to a motor 15 for rotating the wheels. The wheels can rotate independently of each other. The wheels 12 forming the front and rear wheel module may be rotated such that all the wheels of the front wheel module 13 rotate in the same direction and all the wheels 12 of the rear wheel module 14 rotate in an opposite direction or counterrotation with respect to the front wheel module 13. The effect of the counterrotation will prevent the turning of the tractor. This achieves the propulsion of the tractor inside a pipeline. Further, details of the prior art will not be discussed here.

The term tractor apparatus and tractor will be used interchangeably throughout the description and should be understood to mean the same.

Figure 2 is an example of an apparatus according to the invention. The tractor apparatus 20 as shown in the figure comprises a central shaft that extends along a longitudinal axis 21 of the tractor apparatus 20. The longitudinal axis is indicated by means of dotted lines in the figure. The shaft may be understood to mean a longitudinal section extending along the inner region of the tractor apparatus that supports different modules of the tractor apparatus on it. In an aspect, the shaft 21 may also be made of several smaller modules being assembled together. In the example discussed, the shaft is made of five primary modules that comprise: a rear pressure diversion unit 22, a rear drive module 23, a fluid motor 24, a front drive module 25 and a front pressure diversion unit 26. In addition, the shaft may also support a fluid cavity/channel (not shown in fig 2) running through some or all of the different modules and in fluid communication with the modules so as to support change in position and placement of the different modules of the tractor apparatus. The fluid cavity may alternatively be referred to as a fluid channel throughout the application and is intended to mean the same.

Each of these modules will be explained furthermore in detail.

The rear pressure diversion unit 22 is provided at the rear end of the tractor apparatus and comprises a pressure diversion circuit (shown in figure 4) that detects when the pressure to the rear drive module 23 exceeds a predefined threshold limit. On detecting the pressure to be more than the defined threshold to the rear drive module 23, the circuit operates to release the excess pressure on the rear drive module 23. The rear pressure diversion unit 22 may be configured to provide the required amount of pressure to the rear drive module 23 and adjust the pressure during the functioning of the rear drive module 23. The rear pressure diversion unit 22 connects to the rear drive module 23. There may also be needed the option to have a fluid separate fluid channel through an engine housing, enabling us to only have one fluid module building pressure to both drive sections

The rear drive module 23 is connected on one side to the rear pressure diversion unit 22 and to the motor 25 on the other side. The rear drive module 23 comprises a plurality of wheels aligned with an inclination angle along the central shaft 21 of the tractor apparatus 20. The position of the wheels with respect to the shaft 21 can be changed by means of eccentric drive module to achieve an eccentric state with the shaft 21 and the center axis of the tractor apparatus 20. The eccentric drive allows changing the angle and/or tilting of the wheels to achieve desired movement or propulsion of the tractor apparatus 20 by means of the motor.

The wheels of the rear drive module 23 are further connected to the motor 24. The motor 24 may be a single motor that is employed to drive the tractor apparatus 20.

The motor 24 may be a fluid motor employed for driving fluid tractor apparatus such as drilling motor, tubing motor, custom fluid motor etc. The motor will be referred to as fluid motor 24 hereafter. In the example of figure 2, the placement of the fluid motor is central between the rear drive module 23 and front drive module 25, however it is to be understood that the fluid motor 24 is not limited to a central position. In other configurations, the fluid motor 24 may be located either in front of both the front and the rear drive modules 25, 23 or at the back of the front and rear drive modules 25, 23. In other words, the front and the rear drive modules 25, 23 may be connected to the shaft and placed next to each other with the fluid motor 24 placed on one side of modules 25, 23. In some embodiment, the apparatus may also comprise further modules arranged in front of or at the back of the fluid motor.

During operation, when the fluid is supplied to the fluid motor 24, The fluid motor 24 rotates. With the rotation of the fluid motor 24, the motor housing and motor rotor also rotate with a defined number of revolutions per minute. This in turn would affect the tractor apparatus 20 and cause turning of the tractor apparatus 20. In addition, as the front and rear drive modules 25, 23 rotate, the tractor apparatus 20 may rotate.

Further, considering the tractor apparatus as a whole, with front and rear drive modules 25, 23 rotating in counter direction, and addition of the fluid motor 24 it can be desirable to locate the fluid motor 24 in such a position that the fluid motor 24 would not disturb the balance of the front and rear drive module 25, 23 so as to achieve inertia of the tractor apparatus 20,. Hence, the motor 24 is placed such that the rotation of the fluid motor 24 and the motor components (rotor etc) will balance the rotation of the front and rear drive module 25, 23.

In another example, when the fluid motor 24 may be placed in between front and the rear drive modules with the motor position such that the fluid motor’s stator is fixed on one of the drive modules (either the front or rear) and the rotor of the motor is fixed on the other drive module. Such that when the motor rotates, the motor housing and the motor rotor will rotate with the same RPM but in the opposite direction due to the friction from the front and rear drive modules. This in turn, prevents the rotation of the tractor apparatus 20 as a whole.

In another aspect the tractor apparatus 20 also includes a fluid supply means 27. The fluid supply means 27 may be an umbilical, a hose, steel pipe (both threaded and or non-threaded), composite etc. In the example of figure 2, the fluid supply means is an umbilical 27 as described. However, it must be understood that the application does not intend to limit it to the same.

The umbilical 27 carrying fluid or other supplies to the tractor apparatus. In such a scenario, it is important to prevent additional torque to the feedline to prevent turning of the tractor apparatus 20. This scenario is especially relevant when the tractor apparatus is for example used in a hose, pipeline, umbilicals for offshore industry and so on.

The front drive module 25 is essentially the same as the rear drive module 23 and comprises a plurality of wheels. As illustrated in the figure are four wheels, however it must be understood to not be limited to four wheels. The wheels are driven by an eccentric drive module and the position and inclination of the wheels can be varied by the eccentric drives as desired and based on the areas to drive through by tractor apparatus 20 inside the cylindrical body.

In an aspect, the front and rear drive modules 25, 23 are driven by hydraulic or pneumatic cylinders for providing the force to move the wheels and the details will be elaborated in figure 4.

The front pressure diversion unit 26 is in the example in figure 2 arranged on the front end of the tractor apparatus 20 and connected to the front drive module 25. The front pressure diversion unit 26 may adjust the pressure supplied to the front drive module 25 depending of the requirements of the tractor apparatus and the type of pipeline, hose, wells etc. through which the tractor operates. The front pressure diversion unit 26 comprises a circuit that is activated when the pressure on the front drive module 25 exceeds a predefined threshold value and thus the pressure to the front drive module 25 may be adjusted.

In an aspect, a separate fluid cavity/channel is provided and in fluid communication with the front drive module 25, rear drive module 25 and the housing of the fluid motor 24. This fluid cavity/channel may eliminate the necessity of two pressure diversion units and thus support a single pressure diversion unit which is configured to control the pressure of the front and rear drive modules (26, 22).

In another embodiment, the umbilical 27 may also be capable of supplying power, signals for communication and control of the tractor apparatus 21.

Figure 3 illustrates an exploded view of a tractor apparatus, for example one as shown in figure 2. The fluid motor 24 in this example is shown as placed centrally on the tractor apparatus, however the motor as described above may be located elsewhere.

The front and rear drive modules 23, 25 further comprise of front wheel pack 36 and the rear wheel pack 31. The wheel pack 36, 31 may further comprise a plurality of wheels depending on the requirements of the tractor apparatus and the application for which the apparatus is employed. The front and rear wheel axles 35, 32 are also shown.

On either side of the front and rear wheel pack 36, 31 there are hydraulic interfaces 34, 41 that are connected to allow connection to the hydraulic cylinders that are within the front and rear wheel drive modules. The hydraulic interfaces 34, 41 connect to valve housings 30, 39 to facilitate connection to additional valves or interfaces.

In the example depicted in figure 3, the valve housing/body 39 on the front wheel module connects to another interface 38 for additional tools. In an aspect additional tools can be a jetting nozzle, fluid activated tools, etc. The valve housing/body 30 on the side of the rear wheel module 23 connects to an umbilical interface 33 that allows connection to an umbilical or a hose 29.

Further, the valve body 30, 39 may be provided with several pairs of ducts for mounting valves. Rotating the mounting of the valve housing/body 30, 39 by 90 degrees in relation to adjacent components allows to choose the pair of valves to include in the hydraulic system. This in turn increases flexibility in terms of working conditions of the tractor apparatus 20.

Figure 4 illustrates schematically a hydraulic system of a tractor apparatus for propulsion and operations inside a cylindrical body.

As described above, the fluid motor 24 is in fluid communication with the shaft 21 and supplying the fluid required to drive the fluid motor 24 and the front and rear drive modules 25, 23. A main fluid line 28 supplies fluid to the fluid motor 24 via an umbilical that is connected to the tractor apparatus. It should be noted that the majority of fluid is supplied to the fluid motor 24 to drive the motor with respect to its housing and rotor. In this example case, the fluid motor 24 is placed such that, the motor’s stator fixed on one of the front or rear drive module 25, 23 and the motor’s rotor is fixed on the other of the drive modules. When the fluid drives the fluid motor 24, the motor rotates such that the motor stator and the motor rotor will rotate in the opposite directions and attain the same number of revolutions per minute. The fluid motor being connected to the front and rear drive modules 25, 23 on the other sides causes friction as the motor rotates. The friction thus balances the rotational forces acting on the motor itself and the forces on the drive modules 25, 23. As a result, the tractor apparatus 20 itself is prevented from rotation during its operation and propulsion along the cylindrical body.

A small amount of the fluid is also supplied to the front drive module 25 and rear drive module 23. As described above, the eccentric drive can control the front and the rear drive modules, specifically the position of the wheels of the drive modules relative to the shaft/central axis of the apparatus.

The eccentric drive may comprise a hydraulic or a pneumatic drive. The hydraulic or pneumatic drives may comprise hydraulic or pneumatic cylinders which provide the required force to move the wheels of the drive modules radially relative to the shaft. The hydraulic or pneumatic cylinders are further driven by hydraulic fluid/air, which can be provided for example by the umbilical 27 through the cavity for fluid flow running along the shaft 21 or a fluid hose running along the central part of the apparatus 20. In an aspect, there can be arranged cavities in each wheel module, and a fluid hose connecting the cavities. The cavities/fluid hose are in fluid communication with the hydraulic/pneumatic cylinders.

Further, the eccentric drive controls the position of the wheels with respect to the shaft. When the wheels of the front and rear wheel modules 25, 23 are driven by the fluid motor 24, the wheels of the front drive module rotate in one direction and the wheels of the rear drive module rotate in an opposite or counter rotation to the front drive module wheels. These rotations eliminate each other, preventing rotation of the tractor apparatus 20 itself, as long as the wheels rotates with the same rotational speed and the friction caused by the contact between wheels and pipe wall of the cylindrical body through which the tractor apparatus moves are equal.

In an aspect, it is also possible to control the rotation of the wheels of the front and rear drive modules 25, 23 in the same direction if required.

Figure 5 illustrates the operation of the tractor apparatus inside a cylindrical body. As described above, the tractor apparatus 20 is provided with a fluid motor 24 in communication with the cavity/channel (not shown in figure). On either side of the fluid motor 24 are provided front and rear drive modules 25, 23 with their eccentric drive wheels 12, 12’, 12’’.

The drive modules are connected to the front and rear pressure diversion units 26, 22. In an aspect, depending of the type of cylindrical body in which the tractor apparatus is employed for operation, the pressure exerted on the body can be adjusted by means of the pressure diversion unit 22. For example, the pressure required for operation in a pipeline, or well intervention operation may be different from that of water pipeline, process plant pipelines and thus the pressure diversion unit 22 can be configured to provide required pressure to the tractor apparatus 20.

At the rear end of the apparatus is provided a sensor module 15, however it must be understood that several sensor modules 15 may also be provided in addition and not limited to the example described here.

The sensor modules 15 may comprises of one or several sensors such as gyro meter, accelerometer, inclinometer, that may be employed for monitoring the position and orientation of the tractor apparatus 20 within the cylindrical body. In an aspect, additional sensors may also be employed on the sensor module 15 such as sensors for measuring pressure, temperature, humidity, fluid flow, etc. These sensors may be placed on front or rear of tractor apparatus and may be provided with memory tools.

The umbilical 27 supplies the fluid through the cavity in the shaft 21 for operation of the fluid motor 24 and the drive modules 25, 23.

As described above, in an aspect the apparatus does not comprise a separate shaft or similar, but the fluid flows in cavities within the drive modules. The cavities for fluid flow in the drive modules may be connected together directly or via fluid channels. In some embodiments, the drive modules, including fluid flow cavities can be produced as one single part.

Figure 5a shows the tractor apparatus installed inside the cylindrical body for operation. In an example, the cylindrical body 40 may be a pipeline, hose, oil or gas well, open hole etc., but not limited to the same. In this configuration, the tractor apparatus 20 is stationary and the wheels 12 are aligned along the shaft 21 with the diameter of the apparatus being the smallest.

In figure 5b, the eccentric drives move the wheels 12’, 12” from an initial position along the central axis to an eccentric position as shown in the figure. The wheels 12’ have been moved upwards in the cylindrical body 40 and the wheels 12” have been moved downwards in the cylindrical body 40. This radial movement of the wheels causes the wheels 12’ and 12” to come in contact with the inner walls of the cylindrical body 40 as the diameter of the tractor apparatus expands. Further, the contact of the wheels 12’, 12” with the inner walls of the cylindrical body 40 together with force that acts on the grooves in the wheels 12’, 12” may cause the wheels to penetrate into the cylindrical body’s inner wall with slight deformation. This in turn, enables the tractor apparatus 20 to move forward inside the body. As the tractor apparatus 20 moves, the umbilical 27 is driven forward along the body. Thus, the turning forces in the tractor apparatus are balanced to avoid tractor turning or tangling of the umbilicals inside the cylindrical body 40.

In an aspect, the surface contact area of the wheels 12’, 12” of the front and rear drive modules is greater than that of conventional tractors available. Further, depending of the requirements of the operations, the number of wheels can be increased. Due to increase in the contact points of the wheels at the inner wall of the cylindrical body 40, the tractor apparatus is propelled at greater speeds and can provide the required pull even with a shorter length of the tractor apparatus while being flexible and robust in performance.

In figure 4b, the rotation of the wheels 12’, 12” is also observed. The wheels of the front drive module 25 rotate in an opposite direction with respect to the wheels of the rear drive module 23. This in turn, causes the drive modules to travel in a helical path in opposite directions. The opposite or counterrotations balance each other.

Further, the placement of the fluid motor 24 with its rotating components which include motor housing and the motor rotor will balance any additional torque acting on the tractor apparatus 20. Thus, the tractor apparatus 20 moves forward, without being impacted by the rotational forces.

The sensor module15 may monitor and record position, and/or data of the environment surrounding the tractor apparatus 20 in the cylindrical body as the tractor moves forwards.

In an example case, the tractor apparatus may be configured such that, the sensor module 15 may send instructions to a control unit that adjusts the position and orientation as required. In another aspect, the control unit may be located within the tractor apparatus 20 or may be located external to the apparatus 20.

Figure 6a and 6b illustrate sectional view of hydraulic fluid flow line of the tractor apparatus. In the figure 6b a cut sectional view exposes inner fluid cavity 61 or channel through the apparatus components. The fluid cavity/channel 19 carries hydraulic fluid for supply to the fluid motor 24 and the front and rear drive modules 25, 23. The hydraulic fluid is shown in solid gray in the figures and is supplied through interface components 34, 41, valve body 30, 39 and wheel package to the fluid motor 24. On the other side of the fluid motor 24 there can be a corresponding system.

Error! Reference source not found.In figure 6b it can be seen a side cavity or channel 63 that branches from the main channel 19. The side channel 63 supplies the hydraulic fluid to the valve body 30, 39 and further hydraulic pistons in or connected to the wheels of the front and rear drive modules.

Figure 7a and 7b illustrate a sectional view of the front and the rear stator shafts of an tractor apparatus. In 7a and 7b, the shaft of the wheel modules comprises opening 71, 72 for supplying the fluid through the umbilicals to the eccentric drives to move the wheels of the front and rear drive modules. The central shaft may provide a cavity 77, 78 for supplying the fluid. The fluid may be a hydraulic or pneumatic fluid. In addition, the shaft may also comprise additional signal and or power cables 73, 74. The fluid cavity of the shaft may also provide connections 75, 76 for connection to hoses or other hydraulic equipment.

Figure 8 illustrates add-ons to the tractor apparatus, according to an embodiment of the invention. As in, 8a the number of drive sections on both front drive module and rear drive modules may be scaled based on the requirements of the tractor apparatus and the cylindrical area the apparatus needs to propel through. In the example in 8a, the number of drive modules 81, 82 is scaled from one unit to three units as observed in 81.

In another aspect, shown in 8b knuckle joints may be added as an interface to the tractor apparatus 20 to increase flexibility of the apparatus to move through bends and curves. The sections 83, 84 depict front and inner face of the knuckle joint which may be interfaced to the connecting interfaces 38 of the tractor apparatus 20.

Contra gears shown in fig 8c may be employed on the tractor apparatus 20 to keep the torque to minimal for the whole assembly and prevent any additional torque forces from acting on the apparatus or eliminating turning of the apparatus. The teeth 86 and shaft 85 of the contra gears are illustrated in the figure.

In addition, the tractor apparatus may also comprise gear boxes, return gears and mechanical additions. Gear boxes may be added to ensure optimal speed vs torque to specific operations. Return gear may be added to return the rotational direction of the tractor apparatus to reverse the running direction (i.e., of the pressure operated valve). The mechanical additions such as weak-link or burst disc protect the tractor apparatus from higher stress caused by mechanical means and or pressure.

In an aspect, the tractor apparatus can be provided with additional interfaces to allow selection of the number of front and rear drive modules, the number of wheels in each of the drive modules, type of wheels in the drive modules and the type of each module assembled on the tractor apparatus depending on the application the tractor apparatus is employed. Furthermore, additional fittings for bend selection of the tractor apparatus to select the bending radius of the apparatus may also be provided.

In another aspect, the individual modules, components and add-on’s, interfaces provided for the tractor apparatus may be fail safe such that they ensure the tractor apparatus does not get struck in the cylindrical body during operations. In an example, if there are problems with pressure or flow control to the tractor apparatus, the apparatus may reset by a mechanically activated emergency function switch, such that the apparatus continuous to operate without interventions on being powered up again.

In a second aspect, the tractor apparatus itself may be provided with emergency tools or fail-safe mechanisms to handle emergency scenarios. These tools may include an emergency function that may be electric, time, pressure or mechanically activated. An example would be to have a smallest possible cross section in cases where the apparatus needs to be retracted out of the well or pipeline it is operating in, or other cases where a minimal size is desired.

In an embodiment of the invention, the tractor apparatus may be employed in application from the surface of the land. In such a scenario, the tractor apparatus may employ its own push force to provide the required pressure to drive the apparatus. There may not be necessary to have any addition injectors or additional forces employed to attain the required pressure. A deployment lubricator may be employed by the tractor apparatus during such applications. The lubricator may be a pipe, hose, bends or combinations of these and may be directed in any angle with any bend radius or no bend radius at all. Furthermore, the apparatus may be provided with mechanism to guide the fluid supply means into the lubricator through one of: gooseneck, sheave wheels and/or roller guides.

Claims

PATENT CLAIMS

1. An apparatus (20) for performing operations inside a cylindrical body, the apparatus comprising:

- a fluid supply means (27) extending from a rear end of the apparatus for providing fluid to the apparatus;

- at least one pressure diversion unit (26, 22) in fluid communication with the fluid supply means (27);

- a front drive module (25) and a rear drive module (23) in fluid communication with the pressure diversion unit (26, 22); and

- a fluid motor (24) in fluid communication with the front drive module (25) and rear drive module (23), the motor being controlled by a control unit.

2. The apparatus (20) according to claim 1, wherein the fluid supply means for providing fluid to the apparatus (20) is at least one of: an umbilical, a hose, steel pipe (threaded or non-threaded), composite.

3. The apparatus (20) according to claim 1, comprising a cavity/channel (19) for supply of hydraulic or pneumatic fluid, wherein the fluid drives the front drive module (25) and rear drive module (23) for propulsion of the apparatus inside a cylindrical body.

4. The apparatus (20) according to claim 3, wherein the hydraulic or pneumatic fluid is in communication with a hydraulic or pneumatic cylinder employed in the front drive module (25) and the rear drive module (23) of the apparatus.

5. The apparatus (20) according to claim 1, wherein the front drive module (25) and the rear drive module (23) comprise eccentric drives with a tilting mechanism and comprising plurality of wheels of the drive module, wherein the tilting mechanism tilts the plurality of wheels for propulsion of the apparatus in the cylindrical body.

6. The apparatus (20) according to claims 1-5, wherein the wheels of the front drive module (25) rotate in a counter rotate direction with respect to the wheels of the rear drive module (23).

7. The apparatus (20) according to claim 1-6, wherein the motor is placed between the front drive module (25) and the rear drive module (23) and rotates such that, the rotation of the motor with respect to its housing and rotor achieves the same RPM in opposite direction due to friction from the front (25) and rear drive module (23) and prevents turning of the whole apparatus during operation inside the cylindrical body.

8. The apparatus (20) according to claim 1-7, wherein the motor is placed either at the front of or back of the front drive module (25) and the rear drive module (23), wherein the front drive module (25) and the rear drive module (23) are connected through a shaft to each other.

9. The apparatus (20) according to claim 1, wherein the apparatus further comprises a central shaft extending along the inner region of the apparatus and supports different modules of the apparatus.

10. The apparatus (20) according to claim 1, wherein the apparatus further comprises a front pressure diversion unit (26) connected to control pressure of the front drive module (25) and a rear pressure diversion unit (22) connected to control pressure of the rear drive module (25).

11. The apparatus (20) according to claim 10, wherein the front and rear pressure diversion units (26, 22) distributes the hydraulic or pneumatic fluid to the front and rear drive modules (25, 23) to activate the wheels of the drive modules.

12. The apparatus (20) according to claim 1, wherein the apparatus further comprises an interface for providing a plurality of add-ons and scaling components.

13. The apparatus (20) according to claim 1, wherein the add-ons include at least one of: additional drive modules, joints, gears, weaklinks, burst discs, flow activated tools, memory tools, time activated tools and emergency tools or fail safe mechanisms.

14. The apparatus (20) according to claim 1, wherein the cylindrical cavity is one of: a pipeline, flowline, umbilicals, hose, flexible risers bounded and un-bounded.

15. The apparatus (20) according to claim 1, further comprises a sensor module with sensors for measuring temperature, fluid flow, torque, pressure, humidity.

16. The apparatus (20) according to claim 1, wherein the apparatus is configured to be employed from the land surface using lubricators including at least one of: pipe, hose, bends and by means of the push force of the apparatus.

17. The apparatus (20) according to claim 1, wherein the apparatus is configured to guide the fluid supply means into a lubricator through one of: gooseneck, sheave wheels, roller guides.