QUARTER TURN TUBING ANCHOR CATCHER

Abstract

A torque anchor for anchoring well equipment in a well conduit to arrest movement in both longitudinal directions and rotation in a first direction, but not rotation in an opposed second direction. A mandrel connected to the equipment has one or more grooves for slideably receiving respective pins from a drag body on the mandrel. A slip cage on the mandrel houses slips for selectively engaging and disengaging the conduit. Manipulation of the mandrel at surface causes the pins to move within the one or more grooves on the mandrel and the drag body to move toward the slip retainer driving the slips outward to grip the conduit. Further pulling at surface maintains the set position. The anchor is unseta surface by releasing the pull, rotating the mandrel in the second direction, and pushing the mandrel to disengage the slips.

Description

FIELD OF THE INVENTION

The present invention relates to tools for petroleum wells generally, including wells accessing heavy crude. In particular, the present invention relates to a tubing anchor catcher and its use in a system for reducing movement, which may be caused by a downhole pump, within in a well conduit.

BACKGROUND OF THE INVENTION

A tubing string is used within a petroleum well to position downhole tools proximal to one or more underground geological formations that contain petroleum fluids of interest. The tubing string may also be referred to as production tubing or a production string. The tubing string is made up of sections of individual pipe joints that are typically threadedly connected to each other. The tubing string extends within a bore of the well. The well bore is typically completed with casing or liners. The completed well bore may also be referred to as a well conduit. The tubing string can carry various downhole tools into the well conduit. For example, downhole tools can be used for various purposes including anchoring the tubing string within the wellbore at a desired location and to limit movement of the tubing string. Downhole tools can also be used to stimulate and capture production of petroleum fluids. The tubing string is also the primary conduit for conducting the petroleum fluids to the surface.

Known tubing anchors use either a combination of right and left hand threads, or are limited to one thread orientation. Examples of such tubing anchors are shown in U.S. Pat. No. 3,077,933 to Bigelow and in Canadian patent no. 933,089 to Conrad. Disadvantages of such tubing anchors include the expense of manufacturing the threaded portions, the threads may be susceptible to corrosion and the threads may be difficult to, or unable to, unset if they become filled with sand or corroded. With the new technology of fracing, the industry has adopted a heavier weight casing to be able to handle the bends and ‘S’ curves that are drilled today. A heavier weight casing wall makes the interior diameter of the casing smaller. This change in diameter, combined with the wells drilled with deviations and horizontal applications, makes the setting of the older design (multiple revolutions) tubing anchor catchers and packers hard to set as it is hard to feel, or detect, at surface when the tools is set due to the friction on the side walls and having to workout the tubing twist going around bends in the well bore.

Another type of tubing anchor shown in U.S. Pat. No. 5,771,969 and corresponding Canadian patent no. 2,160,647 to Garay avoids the aforementioned threads and instead uses a helical bearing to transform rotational movement into linear movement for setting and unsetting the tubing anchor. The helical bearing also accommodates shear pins for secondary unsetting if required. The use of one component, namely the helical bearing, to perform several functions has the advantage over the previous prior art of being less expensive to manufacture and less susceptible to seizing.

SUMMARY OF THE PRESENT INVENTION

The present invention provides a tubing anchor catcher that acts to reduce or stop movement of a tubing string within a wellbore. The tubing anchor catcher may also catch the tubing string and hold the tubing string in place if a part of the tubing string disconnects or fails above tubing anchor catcher.

One example embodiment of the present invention provides a tubing anchor catcher tool that is positionable within a well conduit for preventing movement of a tubing string. The tool comprises: a mandrel that is connectible at either end to the tubing string, the mandrel comprising a groove; a first cone element that is slidably mountable on to the mandrel, the first cone element comprising a first conical surface; a drag body that is slidably mountable on the mandrel, the drag body comprising a drag member that is sized for frictionally engaging an inner surface of the well conduit, a pin for engaging the groove, and a second conical surface; a biasing member that is slidably mountable on the mandrel adjacent the drag body for engaging the first cone element when the biasing member is compressed; and a slip cage that is slidably mountable on the mandrel, the slip cage comprising a slip that is adapted for engaging the inner surface of the well conduit when the mandrel is rotated a quarter turn relative to the drag body and the conical surface is disposed underneath the slip. Wherein when the second cone element is engaged, the second cone element is slidably moveable underneath the slip.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 is an elevation side view of an example embodiment of a tubing anchor catcher;

FIG. 2 is a mid-line cross-sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a mid-line cross-sectional view of FIG. 1 showing the tubing anchor catcher with its slips extended;

FIG. 4 is a perspective view of an example embodiment of a mandrel for use as part of the tubing anchor catcher of FIG. 1;

FIG. 5 is an enlarged view of an example embodiment of a groove that forms part of the mandrel of FIG. 4, showing a pin from the tubing anchor catcher engaged in the groove, in a run-in position;

FIG. 6 is the view of FIG. 5 showing the pin in a set position;

FIG. 7 is a mid-line cross-sectional view of an example embodiment of a tubing anchor catcher, in the run-in position;

FIG. 8 is a mid-line cross-sectional view of the tubing anchor catcher of FIG. 7, in the set position;

FIG. 9 is a side elevation view of an example embodiment of a tubing anchor catcher;

FIG. 10 is a mid-line, sectional view of the tubing anchor catcher of FIG. 9; and,

FIG. 11 is an exploded isometric view of the tubing anchor catcher of FIG. 9.

FIG. 12 is an enlarged view of a portion of FIG. 12.

FIG. 13 is a side elevation view of an example embodiment of a tubing anchor catcher positioned within a well bore.

FIG. 14 is a cross-sectional view taken along line 14-14 in FIG. 13.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 to 8 depict one example embodiment of a tubing anchor catcher 10. The tubing anchor catcher 10 may be inserted within a well conduit 12 (see FIGS. 13 and 14), such as a wellbore casing. FIGS. 1 and 2 depict the tubing anchor catcher 10 in an unset, or “run-in”, orientation in which it can be run inside the well conduit 12 on a tubing string. Safety subs 14A, B may be attached to a mandrel 20 of the tubing anchor catcher 10 having attachment means, such as an inner threaded lower end 22 and an outer threaded upper end 24. In this embodiment, the tubing anchor catcher 10 may be run down the well conduit 12 while being threadedly connected within the tubing string in the downhole direction indicated by arrow 16. Arrow 17 indicates the opposite direction within the well conduit 12, namely the up-hole direction. It is noted, however, that terms such as “up”, “down”, “forward”, “backward” and the like are used to identify certain features of the tubing anchor catcher 10 when placed in a well conduit. These terms are not intended to limit the tubing anchor catcher's use or orientation. Further, when describing the invention, all terms not defined herein have their common art-recognized meaning.

The tubing anchor catcher 10 has an upper end 10A and a lower end 10B. The tubing anchor catcher 10 may comprise of a drag body 40, a slip cage 60 and a biasing member 94, all of which are mounted about the external surface of the mandrel 20. The drag body 40 houses a drag means, in the form of one or more drag blocks 42, for spacing the tubing anchor catcher 10 away from the inner wall 13 of the conduit 12. The drag blocks 42, for example three or four drag blocks 42, may be generally evenly spaced circumferentially about the tubing anchor catcher 10. Each drag block 42 has a drag spring to urge the outer surface 46 of the drag block against the well conduit's inner wall. Upper and lower drag retaining rings 48, 50 keep the drag blocks 42 removably mounted within the drag body 40. In addition to keeping the tubing anchor catcher 10 spaced from the well conduit 12, the contact of the drag block surface 46 the well conduit's 12 inner wall or surface 13 causes friction that urges the drag body 40 to remain stationary while the mandrel 20 moves within the rest of the tubing anchor catcher 10.

As will be discussed further, the drag body 40 is connected to the mandrel 20 by one or more pins 88 that extends inwardly from the drag body's 40 inner surface to engage an externally facing groove 80 that is on the outer surface of the mandrel 20. As described further below, in one example embodiment, the pins 88 are made from a shearable material.

The slip cage 60, which may also be referred to as a slip retainer, is also mounted on the mandrel 20 adjacent the drag body 40. In particular, the slip cage 60 is mounted on the mandrel 20 above the drag body 40 (i.e. in direction 17). The slip cage 60 may house one or more radially, movable slips 62. For example, three slips 62 are depicted as being evenly spaced about the slip cage 60, although this is not intended to be limiting as the tubing anchor catcher 10 described herein may operate with one or more slips 62. Each slip 62 has an outer surface with teeth 63 for gripping the inner wall 13 upon contact. The teeth 63 may comprise upward gripping teeth 63B and downward gripping teeth 63A. The slip 62 may also have an inner surface with opposed, outwardly inclined edges with an upper edge 64A and a lower edge 64B. A fastener in the form of a socket head cap screw 65 is fastened to the drag body 40 and is located within each of a plurality of associated elongate slots 66 that are defined by the slip cage 60 and spaced circumferentially thereabout, preferably between each slip 62. The cap screw 65 is adapted to contact upper and lower shoulders 68A, B at each end of the associated slots 66, which forms a stop means to prevent the slip cage 60, and the drag body 40, from longitudinally separating.

A cone element 70 is mounted about the mandrel 20 at an upper end of the slip cage 60. The cone element 70 comprises an upper edge 70A and a lower edge 70B. The lower edge 70B forms a first conical surface whose inclined surface wedges under the slips 62 when the tubing anchor catcher 10 is moved into a set position. Likewise, an upper edge of the drag body 40 forms a second conical surface 54 whose inclined surface also wedges under the slips 62 when the tubing anchor catcher 10 is moved into a set position. However, the first and second conical surfaces 70B, 54 may not actively contact the slips in the unset position. A slip spring 76 urges each slip 62 radially inwardly into the slip cage 60 and away from the well conduit 12 while in the unset position (FIG. 2).

FIG. 3 depicts the tubing anchor catcher 10 in the set position with the slips 62 extended outwardly from the slip cage 60 for engaging the inner surface 13 of the well conduit 12. The slips 62 are extended due to either or both of the conical surfaces 70B, 54 moving underneath the slips 62. For example, when the conical surface 54 moves underneath the slip 62, the spring 94 may be compressed, from below due to the movement of the mandrel and the tension in the tubing string, and force the first conical surface 70B underneath the slip 62.

FIG. 4 depicts the mandrel 20 as including an upper end 20A and a lower end 20B. As described above, the upper and lower ends 20A, B may each comprise threaded connections for connecting the mandrel 20 to the tubing string. As shown in FIG. 2, the upper end 20A comprises a box threading and the lower end 20B comprises a pin threading. At least one groove 80 is formed on the mandrel's outer surface 26, as best seen in FIGS. 4 to 6. The groove 80 is dimensioned (width, depth) to slidingly accommodate a protruding portion of the pin 88 that extends therein threaded through a hole 56 in the drag body 40. The lower retaining ring 50 retains the drag blocks 42 within the drag body 40. The tubing anchor catcher 10 may comprise one or more sets of grooves 80 and pins 88. For example, the tubing anchor catcher 10 may have three sets of grooves 80 and three sets of associated pins 88 that are generally evenly radially spaced about the mandrel 20.

As depicted in FIGS. 5 and 6, the groove 80 may comprise a C-shape with shoulders 82 and 86 defining a first arm 80A of the groove 80 and shoulders 84 and 92 defining a second arm 80B of the groove 80. The two arms 80A, B of the groove 80 are connected by central portion 80C that is defined by walls 86, 87, 89 and 90. Wall 90 separates the first and second arms 80A, B.

As seen in FIGS. 5 and 6, which is an enlarged view of groove 80, a portion 88a of the pin 88 protudes into the groove 80 and is seated against the shoulder 92 in the run-in (i.e. un-set) position with the slips 62 retracted within the sip cage 60. To move the pin 88 to the set position at shoulder 82, the tubing string can be manipulated at surface so as to move axially, i.e. by pulling or pushing, and rotationally, i.e. by turning, so as to similarly manipulate the mandrel 20. The manipulation at surface may articulate the tubing anchor catcher 10 between the run-in position and a set position. Due to the drag blocks 42 frictionally engaging the inner surface 13 of the well conduit 12, the drag body 40 and the slip cage 60 remain relatively fixed as the mandrel 20 and the rest of the tubing string, are manipulated from surface. As manderel 20 is pulled, for example about one inch, in direction 17, the pin 88 slides relative to mandrel 20 in direction A so as to engage the shoulder 84. Thereafter, the mandrel 20 can be lowered, for example about 6 to 7 inches, and turned, for example, a quarter turn to the left (i.e. about 90 degrees). The turning is about the longitudinal axis of the tubing string and, therefore, the tubing anchor catcher 10. This manipulation causes the pin 88 to move from shoulder 84, generally along walls 89, 87 and 86 to rest in shoulder 86 of the first arm 80A. When the pin 88 is in shoulder 86, the tubing anchor catcher 10 is in a pre-set position. The tubing string, and the mandrel 20 can be turned freely to the left. Pulling the tubing string and, therefore, the mandrel 20 upwards, at least about an inch, in direction 17 will cause the pin 88 to move into shoulder 82. When the pin 88 is in shoulder 82, at least the conical surface 54 has moved under the slips 62 and the tubing anchor catcher 10 is set with the slips 62 extending outwards from the slip cage 60 to engage the inner surface 13 of the well conduit 12.

In this embodiment, when viewed in vertical elevation with the top of mandrel 20 upwards, groove 80 is in the shape of a reverse “C”, although this is not intended to be a literal graphical description of shapes that will work, as other shapes will work other than exact C-shapes as may mirror images of the groove 80.

To release the slips 62, the tubing string and, therefore, the mandrel 20 can be manipulated at surface. For example, the mandrel 20 can be moved relative to the rest of the tubing anchor catcher 10, so that the pin 88 moves out of shoulder 82. As shown in FIG. 6, the mandrel 20 can be pushed down so that the pin 88 moves along line F. With a quarter turn to the left the pin will move along line H and then a straight pulling up of the tubing string and mandrel 20 will cause the mandrel 20 to move so that the pin 88 ends up in shoulder 84. When the pin 88 has moved out of the first arm 80A of the groove 80, the conical surface 54 moves out from under the slips 62 and the spring 76 will cause the slips 62 to retract back into the slip cage 60.

When the tubing anchor catcher 10 is in the set position and in the event of a break in the tubing string, etc, which may cause the tubing string to fall down into the well (i.e., in direction 16), the tension in the tubing string is lost. This causes the weight of the tubing string to bear on the upper safety sub 14A, which will bear on the biasing member 94. The biasing member 94 will compress, from the weight of the tubing string above, and act against the upper edge 70A of the cone 70. This action causes the upper teeth 64A to more directly engage and bite into the inner surface 13 of the well conduit 12. For example, the greater the amount of tubing string weight that compresses the spring 94, the harder, or more directly, the upper teeth 64A will engage the inner surface 13 of the well conduit 12. When the downwardly gripper teeth 64A are more directly engaged into the inner surface 13 of the well conduit 12, the upper teeth 64A can hold the weight of the tubing string above the tubing anchor catcher 10, for example, until such time that the tubing string can be recovered at surface.

If it is not possible to move pin 88 in the groove 80 so as to unset slips 62, for example due to packing of sand or other materials into the groove 80, the slips 62 may be unset by applying a sufficient upward tension on the tubing string and the mandrel 20. In one embodiment, the upward tension is of a sufficient amplitude to shear the pins 88, which form the primary connection between the drag body 40 and the mandrel 20. Then the mandrel 20 may move upward (i.e. in the direction of arrow 17), relative to the drag body 40, which causes the second conical surface 54 of the drag body 40 to move out from under the slips 62. This allows the slips 62 to retract from contacting the inner surface of the well conduit. When the slips 62 are retracted, the tubing anchor catcher 10 may be pulled out of the well conduit 12. For example, the pin 65 may engage the lower shoulder 68B of the slot 66 so that the slip cage 60, and the drag body 40 do not separate. Alternatively, or additionally, the lower edge of the catcher body 40 may engage the lower safety sub 14b as the tubing string is pulled upwards towards the surface (i.e. in direction 17).

FIGS. 9 to 12 depict an alternative embodiment of a tubing anchor catcher 100 with an upper end 100A and a lower end 100b. The tubing anchor catcher 100 may comprise many of the same features as tubing anchor catcher 10. For example, one difference between the two tubing anchor catchers 10, 100 is that the pin 88 of the tubing anchor catcher 10 may be sheared as a secondary release mechanism, as described above. In contrast, the tubing anchor catcher 100 may comprise a pin 188 that is not designed to shear as a secondary release mechanism. The tubing anchor catcher 100 may comprise one or more shear pins 72 that are mounted on the lower cone 41 to drag body 40. The shear pins 72 are made of a material that will shear in response to a lower shearing force than the shear force required to shear the pin 188. The second conical surface 54 is formed on the upper end of cone 41 (see FIG. 12). Cone 41 slidably mounts about the external surface of the mandrel 20 so that conical surface 54 in combination with conical surface 70B on cone 70 compress together along mandrel 20 to force slip 62 into the set position, as described above. The shear pins 72 provide a secondary release of slips 62 by the application of a sufficient pulling force to the tubing string so as to shear the shear pins 72. When the shear pins 72 are sheared, the conical surface 54 can move from under the slips 62 and the slips 62 can retract away from the inner surface 13 of the well conduit 12.

The tubing anchor catchers 10, 100 are thus designed to anchor the tubing string from movement longitudinally along the well (in both directions, up and down the well) and from rotating. The anchoring is achieved by simple setting and release procedures that require relatively little movement of the tubing string. In this instance, setting is achieved by a small pull and left hand rotation of the mandrel 20 (via the tubing string) that is adequate for the pins 88, 188 to travel the short distances within the groove 80. Further, both tubing anchor catchers 10, 100 can prevent a broken tubing string from falling into the well bore by the compression of the spring 94 causing the downward gripping teeth 63A to grip the inner surface 13 of the well conduit 12, as described above.

In one optional embodiment of the present invention, the slips 62 may be configured to center either or both of the tubing anchor catchers 10, 100 within the well conduit 12 by radially extending from the slip cage 60 (see FIGS. 13 and 14). This may provide one or more by-pass spaces 78 between the tubing anchor catchers 10, 100 and the inner surface 13 of the well conduit 12, which may create high flow areas for fluids (e.g. gas) and solids (e.g. sand) to pass by the tubing anchor catchers 10, 100. The by-pass spaces 78 may also allow coil tubing to extend more easily past the tubing anchor catcher 10, 100. In the FIG. 14, which is provided by way of example only, depicts by-pass spaces 78 with 1.0 inch (25.4 mm) radial clearance that are created between the 4.5 inch (114.3 mm) OD of the slip cage 60 and the 6.5 inch (165.1 mm) ID of the well conduit 12.

This optional embodiment of the tubing anchor catchers 10, 100 may permit capillary cable to be carried downhole via the large by-pass spaces 78. In particular, the fact that the tubing anchor catchers 10, 100 is set and unset by longitudinal motion and a limited, quarter turn, permits its use with the capillary cable since the tubing anchor catchers 10, 100 may avoid wrapping of the cable around the tubing anchor catchers 10, 100. In contrast, prior art anchors that require multiple full (360 degree) rotations—between two to nine full rotations for setting and unsetting—cause an undesirable wrapping of the cable around the anchor, which can damage the cable. Alternately, the cables must be pre-wrapped when inserted with these prior art anchors, so that they unwrap as the anchor is twisted during setting, which is tedious and undesirable.

Optionally, the drag blocks 42 may be hardened, in comparison to prior art drag blocks, for a longer operational life. The slips 62 may optionally be made of solid high strength metal for superior durability and grip on the well conduit wall 13, and Inconel™ type springs 76 are employed for improved resistance to H₂S and CO₂. Further, the surface of the mandrel 20 may optionally be coated with Teflon® for improved resistance to H₂S and CO₂, and to help maintain mandrel strength.

While the above disclosure describes certain examples of the present invention, various modifications to the described examples will also be apparent to those skilled in the art. The scope of the claims should not be limited by the examples provided above; rather, the scope of the claims should be given the broadest interpretation that is consistent with the disclosure as a whole.

Claims

1. A tubing anchor catcher tool that is positionable within a well conduit for preventing movement of a tubing string, the tool comprising: a. a mandrel that is connectible at a first end and a second end within the tubing string, the mandrel comprising an externally facing groove;b. a slip cage that is slidably mountable about the mandrel, the slip cage comprising a slip that is adapted for engaging the inner surface of the well conduit;c. a first cone element that is slidably mountable about the mandrel, adjacent the slip cage towards a first end of the tool, the first cone element comprising a first conical surface;d. a drag body that is slidably mountable about the mandrel, adjacent the slip cage towards a second end of the tool, the drag body comprising a drag member that is sized for frictionally engaging an inner surface of the well conduit, a pin for engaging the externally facing groove, and a second conical surface; ande. a biasing member that is slidably mountable about the mandrel adjacent the first cone element for engaging the first cone element when the biasing member is compressed; wherein the tool is articulatable between a run-in position and a set position, when in the run-in position the slip is retracted into the slip cage and when in the set position at least the second conical surface is moved underneath the slip for extending the slip outward from the slip cage.

2. The tool of claim 1, wherein the first end of the tool is an upper end and the second end of the tool is a lower end.

3. The tool of claim 1, wherein the externally facing groove comprises a C-shape with a first arm and a second arm that are connected by a central portion.

4. The tool of claim 3, wherein in the run-in position, the pin is positioned within a shoulder of the second arm of the externally facing groove.

5. The tool of claim 3, wherein in the set position, the pin is positioned within a first shoulder of the first arm of the externally facing groove and the drag body is closer to the biasing member than when the tool is in the run-in position.

6. The tool of claim 5, wherein the tool is moveable to a pre-set position, wherein the pin is positioned within a second shoulder of the first arm of the externally facing groove, the second shoulder of the first arm is opposite to the first shoulder of the first arm.

7. The tool of claim 6, wherein the pin is moveable within the externally facing groove between the shoulder of the second arm to the second shoulder of the first arm by longitudinally moving the mandrel in a first direction relative to the drag body, then in an opposite second direction with a quarter turn relative to the drag body, the pin is movable from the second shoulder of the first arm to the first shoulder of the first arm by moving the mandrel in the first direction.

8. The tool of claim 1, wherein when the tool is in the set position, the first cone element is movable under the slip due to the biasing member being compressed.

9. The tool of claim 1, wherein the pin is shearable for providing a secondary release mechanism.

10. The tool of claim 1, further comprising a second cone element that is mountable about the mandrel between the drag body and the slip cage, wherein the second cone element defines the second conical surface.

11. The tool of claim 10, wherein the second cone element is connectible to the drag body by one or more shear pins, wherein the one or more shear pins are shearable at a lower shear force than the pin and the one or more shear pins provide a secondary release mechanism.

12. The tool of claim 1, wherein the slip comprises upward gripping teeth and downward gripping teeth.

13. The tool of claim 1, wherein the drag body further comprising a cap screw that extends outwardly from the drag body through a slot that is defined by the slip cage, wherein the cap screw and the slot prevent the drag body and slip cage from longitudinally separating.

14. The tool of claim 1, wherein the slip comprises at least two slips.

15. The tool of claim 14, wherein when the tool is in the set position, the at least two slips are engageable with the well conduit for centralizing the tool.

16. The tool of claim 14, wherein when the tool is in the set position, the at least two slips define a by-pass space therebetween.

17. The tool of claim 14, wherein the drag body further comprising at least two cap screws that extend outwardly from the drag body each through an associated slot that is defined by the slip cage, wherein the at least two cap screws and the associated slots prevent the drag body and slip cage from longitudinally separating, and wherein the at least two cap screws and the associated slots are positioned between the at least two slips.

18. The tool of claim 1, wherein the mandrel comprises at least two externally facing grooves that are associated with at least two pins of the drag body.

19. The tool of claim 1, wherein the at least two externally facing grooves and the at least two pins are generally evenly radially spaced about the tool.