HK1210245B - Apparatus and method for sensing a pipe coupler within an oil well structure - Google Patents

Description

Device and method for detecting a pipe connection in an oil well structure

Background

1. Field of the invention

The present invention relates generally to drilling wells, and more particularly to an apparatus and method for detecting pipe joints within a well structure.

2. Description of the related Art

In oil and gas production, a well is formed by an outer casing located within a wellbore and may optionally be surrounded by cement. The well may in turn comprise a production tubing or tool for operation or production in the well. Due to the potentially high pressures within the well from hydrocarbons extracted from the hydrocarbon producing formation, many types of shut-off valves, casings and other means for isolating and controlling the intake, such as, by way of non-limiting example, the well-known Christmas tree or snubbing rig.

The well structure may include a shut-off valve for closing off or otherwise completely or partially sealing the well head at the will of the user. In particular, a common design for such valves is a pipe ram that uses a pair of opposing rams movable along a plane perpendicular to the wellbore. The rams may be moved along the plate by pistons or the like and are operable to move out of the central passage of the well or be pressed together to seal the well. The rams may be of the full shut-off or shear type to completely seal a well, or of the pipe ram type, wherein when the two rams are squeezed together, the two rams each include a semi-circular bore sized to accommodate passage of a pipe therethrough. Such pipe rams are commonly used in snubbing drilling rigs to seal around the drill bit or production tubing and to isolate the well from the external environment below the pipe rams while allowing the drill bit or production tubing to remain in the well or to be pulled or inserted into the well.

One difficulty with typical oil and gas wells is that it is difficult to determine the location of the joints on the tool or production tubing. Such strings are typically formed of a plurality of pipes joined end to end by threaded connections. Conventionally, such threaded connections are placed at the respective ends and provided with reinforced pipe enlargements, providing larger and stronger pipe sections to be gripped by tools and the like. Such tool joints have a larger cross-section than the rest of the pipe. Disadvantageously, such enlarged diameters of the tool joints may interfere with proper operation of the pipe rams, which attempt to close at such tool joint locations or upon extraction or insertion of a pipe when at least one ram is provided to contain pressure. Such an event is commonly referred to as tripping, which may risk the tool joint being pulled or pushed into the closed pipe ram thereby damaging the pipe and/or pipe ram.

Disclosure of Invention

In accordance with a first embodiment of the present invention, a system for determining an outer diameter of a metallic object within a well structure is disclosed, the system comprising: a spool connectable in line with a well structure, the body having a central bore passing therethrough along a central axis corresponding to the central bore of the well structure and an outer surface, the spool including a plurality of blind bores extending radially inward from the outer surface. The system further includes at least one ferromagnetic body capable of being positioned in one of said plurality of blind holes, each said ferromagnetic body having a magnet at an end thereof, and at least one sensor associated with at least one said ferromagnetic body, said at least one sensor operable to output a signal indicative of a diameter of said metal object positioned within said central hole.

The magnet may comprise a rare earth magnet. The magnet may comprise an electromagnet. The ferromagnetic body may comprise a sleeve. The ferromagnetic body may comprise a solid cylinder. The magnet may be located at an end of the ferromagnetic body adjacent to the central bore of the bobbin. The magnet may be located at an end of the ferromagnetic body distal to the central bore of the bobbin.

The sensor may be located at an end of the ferromagnetic body adjacent to the central bore of the bobbin. The sensor may be located within the sleeve.

The bobbin may include a plurality of connection holes extending through the bobbin parallel to the central axis. The blind hole may be located between the connection holes. The bobbin may be formed of a substantially non-magnetic alloy. The bobbin may be formed of a nickel-chromium based alloy. The at least one sensor may each comprise a hall effect sensor.

At least one pair of blind holes may be connected to each other by a bridging rod. A first pair of the blind holes may be located on opposite sides of the body. The bridging rod may comprise a tubular element extending between the sleeves of the at least one pair of blind holes. The bridging rod may comprise a solid member extending between the sleeves of the at least one pair of blind bores. The bridging rod may be formed of a ferromagnetic material.

The system may further comprise a display operable to receive the output signal from the at least one sensor and to display an output to a user indicating the width of the metal object within the central bore.

Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of embodiments of the invention in conjunction with the accompanying figures.

Drawings

In the drawings which illustrate embodiments of the invention, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a top end sectional view of a well having an outer casing and a production tubing therein and provided with a means for detecting the position of a pipe joint;

fig. 2 is a perspective view of an apparatus for detecting the position of a pipe joint according to a first embodiment of the present invention;

fig. 3 is an exploded view of a device for detecting the position of a pipe joint according to a first embodiment of the present invention;

FIG. 4 is a cross-sectional view of the device of FIG. 3 taken along line 4-4;

FIG. 5 is a cross-sectional view of the device of FIG. 3 taken along line 5-5;

FIG. 6 is a schematic diagram showing an output showing the voltage generated by the sensor of the apparatus of FIG. 3 when a tool joint is passed therethrough;

FIG. 7 is a cross-sectional view of an alternative embodiment of an apparatus for routing the position of a coupler taken along line 5-5.

Detailed Description

Referring to FIG. 1, a well assembly, generally designated 10, is located within a borehole 8 of a soil formation 6. The well assembly includes a well casing 12 having a top flange 14, the top flange 14 being secured to a pipe ram 16 or any other desired wellhead equipment. It will be appreciated that the apparatus may be placed anywhere within the well, such as, in non-limiting examples, a casing, snubbing equipment, a blowout preventer or any other well device. It will also be appreciated that, whereas only a single pipe ram is shown in figure 1 for clarity, it will be appreciated that many arrangements will include more than one wellhead member. As shown in fig. 1, in accordance with a first embodiment of the invention, a well assembly includes a device for detecting pipe joints, generally indicated at 20, and one or more top pipes, well members or other equipment 18 positioned thereon. A production or tool string 15 is located within the casing and includes a plurality of tool joints 17 along itself.

The apparatus 20 detects the presence of the tool joint 17 and outputs a signal to the display 80 indicating to the user that the tool joint 17 is located within the apparatus 20 to allow the user to advance the production or tool string 15 a predetermined distance within the casing 12 to prevent engagement of a pipe ram 16 or other wellhead equipment on the tool joint.

Referring to fig. 2, the device 20 includes a body 22 having a plurality of sensor bores 40 therein, each sensor bore 40 adapted to receive a sleeve and a sensor therein. The body 22 comprises an annular or ring-shaped bobbin having inner and outer surfaces 24 and 26, respectively, and extending between top and bottom surfaces 28 and 30, respectively. As shown in fig. 1, the inner surface 24 and the outer surface 26 are substantially cylindrical about a central axis 32 of the barrel 22. The inner surface 24 defines a central passage 34 extending therethrough that is sized and shaped to correspond to the interior of the sleeve 12. As shown in fig. 2 and 4, the top and bottom surfaces are substantially flat along a plane perpendicular to axis 32, and optionally may include a seal groove 35 extending annularly therearound for receiving a seal ring, as is well known in the art.

The spool 22 includes a plurality of bolt holes 36 extending through the spool between the top surface 28 and the bottom surface 30 along an axis parallel to the central axis 32. Bolt holes 36 are used to pass through fasteners, such as bolts 38 passing through the bolt holes as shown in FIG. 1, to secure the spool sleeves in line to other components of the well assembly 10 according to methods known in the art.

The barrel 22 also includes a sensor bore 40 extending into it from the exterior surface 26. As shown herein, the sensor bore 40 is a blind bore that extends to a bottom depth within the barrel at a distance less than the distance from the outer surface 26 to the inner surface 24. In this manner, the sensor bore 40 will provide a barrier, generally indicated at 42 in FIG. 4, between the sensor bore 40 and the central passage 34 to maintain the seal provided by the cartridge 22. The dam wall 42 may have a thickness selected to provide sufficient burst strength of the spool, according to known methods. Optionally, the sensor bore 40 may extend completely through the barrel to the inner surface 24. Referring to FIG. 5, the bolt holes 36 may be equally spaced about the spool with the sensor holes extending through the spool at locations between the bolt holes. As shown in fig. 5, however, other orientations may be used and the sensor holes 40 may be aligned around the central passage 34 along a common plane that is perpendicular to the axis 32 of the central passage.

The barrel 22 may have any depth between the top surface 28 and the bottom surface 30 necessary to accommodate the sensor bore 40. In a non-limiting example, the bobbin may have a depth of between 3.5 and 24 inches (89 and 610mm), with a depth of about 4 inches (102mm) being found particularly beneficial. Additionally, the bobbin will be selected to have a corresponding bobbin to be selectedThe inner diameter of the inner surface 24 of the inner passage for the sleeve 12, and the diameter of the outer surface 26 to provide sufficient depth for the sensor bore 40. In practice, an outer diameter between 4 and 12 inches (102 and 305mm) greater than the inner diameter has been found to be beneficial. The bobbin 22 may be formed of a non-magnetic material, such as, in a non-limiting example, a nickel-chromium based alloy, such as manufactured by Special metals IncIt will be appreciated that other materials may be used. For example, in a non-limiting example, duplex stainless steel and super duplex stainless steel, provided they do not interfere with the sensor operation described below.

Referring to fig. 3, an exploded view of the device is shown with the sleeve 50 engageable within each sensor bore and the sensor 70 engageable within the sleeve 50. The sleeve 50 comprises a tubular member extending between first and second ends 52 and 54, respectively, and having inner and outer surfaces 56 and 58, respectively. As shown in fig. 4, the outer surface 58 of the sleeve is selected to closely correspond to the sensor bore 40 in the barrel 22. The sleeve 50 is formed of a generally ferromagnetic material, such as steel, for conducting magnetic flux, as will be described more fully below. The sleeve 50 is selected to have a sufficient outer diameter to be received in the sensor bore 40 and a sufficient inner surface diameter to receive the sensor 70 therein. In a non-limiting example, a diameter of the inner surface of between 0.5 and 1 inch (13 and 25mm) has been found to be beneficial. The sleeve 50 also has a length sufficient to accommodate the sensor 70 therein, such as, in a non-limiting example, between 0.5 and 3 inches (13 and 76 mm). The outer diameter of the sleeve 50 may also be arbitrarily selected to allow the sleeve to be secured within the sensor bore by an interference fit or using adhesives, fasteners, plugs, or the like. The sleeve 50 may also be selected to have an outer diameter of sufficient size to have an interference fit with the sensor bore 40.

The sleeve 50 also includes a magnet 60 at its first end 52. The magnet 60 is selected to have a strong magnetic field. In particular, rare earth magnets or electromagnets have been found, such as neodymium, samarium-cobalt, in non-limiting examples. Optionally, the magnet 60 may also be nickel plated. The magnet 60 is located at the first end 52 of the sleeve 50 and is held in place by the magnetic field strength of the magnet. Optionally, sleeve 50 also includes a gap 51 of up to 1/2 inch (13mm) between magnet 60 and retaining wall 42, although other distances may be used.

The sensor 70 is inserted into the open second end 54 of the sleeve and is retained within the sleeve by suitable means, such as, in a non-limiting example, adhesives, threads, fasteners, and the like. The sensors 70 are selected to provide output signals responsive to magnetic fields in their vicinity. In a non-limiting example, the sensor 70 may comprise a magneto-sensitive sensor, such as a Hall-effect sensor, although it will be appreciated that other sensor types may be employed. In particular, Hall-effect sensors are found, such asThe manufactured sensor, model SS496a1, is particularly beneficial, however, it will be appreciated that other sensors will also be suitable. As shown in fig. 4, the sensor may be located substantially in the middle of the sleeve 50, although it will be appreciated that other locations within the sleeve may be beneficial. The sensor includes an output cable 72 extending therefrom. The output cable 72 is wired or otherwise connected to the display and is therefore operable to provide an output signal representative of the width of a metal object located within the central passage 34 (such as a drill string).

Referring to fig. 6, output 82 may show a voltage signal output by one or more sensors versus time. During a first time period, when the main body of the conduit is pulled through the barrel 22, the voltage signal will be at a first level, generally indicated at 84. As the tool joint 17 is pulled through the spool 22, the voltage output of the sensor 70 will increase due to the increasing diameter of the metal object within the central passage 34, generally indicated at 86. After the tool joint 17 has passed through the barrel, the voltage will return to the lower level 88. Thus, the display 80 will indicate to the operator when the tool joint 17 is within the sleeve. Thereafter, the operator will be able to advance the production or tool string 15 a known distance in order to ensure that the pipe rams 16 or other equipment avoid the tool joints 17.

Referring to fig. 2, the device may be provided with a bridging rod 90 extending between a pair of opposed sleeves 50. The bridging rod 90 may be formed of a substantially ferromagnetic material and is adapted to be secured in the sensor bore 40. The bridging rod 90 may be solid or hollow and is operatively connected to the sleeve 50 within the sensor bore 40. The bridging rod 90 acts as a magnet and sensor coupled to opposite sides of the barrel 22, thereby increasing the field of view. As shown in fig. 2, the device also includes a central bridging rod 90a extending between the sensor holes 40 on opposite sides of the bobbin 22, and a pair of side bridging rods 90b extending between the pair of sensor holes 40 on one side of the central bridging rod 90 s. It will be appreciated that other arrangements may be used, such as the removal of side or central bridging rods.

Referring now to FIG. 7, an alternative embodiment of the present invention is shown with sensor assemblies 100 located in some of the sensor holes 40. The sensor assembly 100 is formed by placing the sensor 70 within the sensor bore adjacent the end of the central passage 34. Also located within the sensor bore 40 is a steel rod 102 having a magnet 60 at its distal end. As shown in fig. 7, an optional sensor cover 104 may also be positioned thereon to protect the sensor assembly 100 from fluid and debris ingress and damage due to impact. The sensor assembly 100 may be located within each sensor hole 40 or only within a portion of the sensor hole. As shown in fig. 7, in a non-limiting example, a sensor assembly 100 may be located in each second sensor hole 40, with the sensor hole in between having a magnet 60 located therein.

While specific embodiments of the present application have been described and illustrated, such embodiments should be considered illustrative only and not as limiting the invention, which is defined in accordance with the following claims.

Claims (21)

1. A system for determining an outer diameter of a metallic object within a well structure, the system comprising:

a barrel connectable in line with the well structure, the barrel having a central bore and an outer surface, the central bore passing through the barrel along a central axis corresponding to the central bore of the well structure, the barrel including a plurality of blind bores extending radially inward from the outer surface;

at least one ferromagnetic body capable of being positioned in one of said plurality of blind holes, each said ferromagnetic body having a magnet at an end thereof; and

at least one sensor, each of said at least one sensor associated with one of said at least one ferromagnetic-based object, said at least one sensor operable to output a signal indicative of a diameter of said metallic object located within said central bore.

2. The system of claim 1, wherein the magnet comprises a rare earth magnet.

3. The system of claim 1, wherein the magnet comprises an electromagnet.

4. The system of claim 1, wherein the ferromagnetic body comprises a sleeve.

5. The system of claim 1, wherein the ferromagnetic-based body comprises a solid cylinder.

6. The system of claim 1, wherein each of the magnets is located at an end of the ferromagnetic body adjacent to the central bore of the spool.

7. The system of claim 1, wherein each of the magnets is located at an end of the ferromagnetic body distal from the central bore of the bobbin.

8. The system of claim 1, wherein each of the sensors is located at an end of the ferromagnetic body adjacent to the central bore of the spool.

9. The system of claim 4, wherein the at least one sensor is located within the sleeve.

10. The system of claim 1, wherein the spool includes a plurality of connection holes extending through the spool parallel to the central axis.

11. The system of claim 10, wherein the blind hole is located between the connection holes.

12. The system of claim 1, wherein the bobbin is formed of a substantially non-magnetic alloy.

13. The system of claim 12, wherein the bobbin is formed from a nickel-chromium based alloy.

14. The system of claim 1, wherein each of the at least one sensor comprises a hall effect sensor.

15. The system of claim 1, wherein at least one pair of blind holes are connected to each other by a bridging rod.

16. The system of claim 15, wherein a first pair of the blind holes are located on opposite sides of the bobbin.

17. The system of claim 15, wherein the bridging rod comprises a tubular element extending between the at least one pair of blind holes.

18. The system of claim 15, wherein the bridging rod comprises a solid element extending between the at least one pair of blind holes.

19. The system of claim 15, wherein the bridging rod is formed of a ferromagnetic material.

20. The system of claim 1, further comprising a display operable to receive the output signal from the at least one sensor and to display an output to a user indicating a width of the metal object within the central aperture.

21. A system for determining an outer diameter of a metallic object within a well structure, the system comprising:

a barrel connectable in line with the well structure, the barrel having a central bore and an outer surface, the central bore passing through the barrel along a central axis corresponding to the central bore of the well structure, the barrel including a plurality of blind bores extending radially inward from the outer surface; and

at least one sensor assembly positionable in one of the plurality of blind bores, one of the at least one sensor assembly comprising:

at least one ferromagnetic body having a magnet at a first end thereof; and

at least one sensor located at a second end of the at least one ferromagnetic body and operable to output a signal representative of a diameter of the metallic object located within the central bore.