Expandable packer, and method for seating an expandable packer

[0002] 1. Field of the Invention

[0003] The present invention relates to the field of expandable downhole tools. More particularly, the present invention relates to an expandable packer having two separate components for isolating downhole areas within a wellbore. The present invention also relates to a method for seating a packer in a wellbore.

[0004] 2. Description of Related Art

[0005] The use of packers for fluidly sealing portions of a wellbore is well known. Packers are most commonly used to isolate downhole formations by sealing the annular space between a production tubing and a wellbore casing. By sealing the annulus, hydrocarbon producing zones can be isolated from other regions within a wellbore, thereby preventing migration of formation fluid or pressure between zones or behind the production tubing.

[0006] Modern packers are typically set in a wellbore through fluid activation. The packer is lowered into the wellbore on the lower end of a tubular working string. Mud or other material is then pumped down the tubular under pressure. This fluid pressure activates a seal element which is expanded to engage the inner wall of the casing.

[0007] Packers typically comprise an expandable body having a hollow interior for defining an open flow path. The expandable body includes an inner elongated hollow mandrel with a hydraulic piston movably disposed upon the external surface of the mandrel. The piston is movable between an initial “running” position and a final “setting” position. An external sleeve is engaged by the piston when it moves between the running and setting positions. The external sleeve engages slips that expand to anchor the tool body to the well casing. A sealing element responsive to sliding movement of the external sleeve is positioned below the slips for forming a seal between the tool body and the casing at a position near the lower end portion of the tool body. The sealing element typically defines upper and lower retaining rings to fluidly seal the annulus between the tubing and the casing.

[0008] Technology for expanding packer elements against casing is disclosed in certain patents. U.S. Pat. No. 6,041,858 issued in 2000 to Arizmendi discloses a packer having two separate body sections, and a deformable material therebetween. The deformable material is extruded into the annular space between the tubing and the casing by application of a vertical force between the first and second body sections.

[0009] U.S. Pat. No. 4,753,444 to Jackson et al. (1988), discussed in the Arizmendi ('858) patent, discloses a packer having a conventional sealing element located around the outside of a mandrel. Anti-extrusion rings and back-up rings contain the seal element ends and are compressed to radially expand the seal element outwardly into contact with the well casing. Additional patents referenced include U.S. Pat. No. 4,852,649 to Young (1989), U.S. Pat. No. 5,046,557 to Manderscheid (1991), U.S. Pat. No. 5,096,209 to Ross (1992), U.S. Pat. No. 5,195,583 to Toon et al. (1993), and U.S. Pat. No. 5,467,822 to Zwart (1995).

[0010] One limitation found within conventional packers is the extent to which a secure seal can be obtained between the exterior sealing element and the interior of the casing. In this respect, a secure seal of the tubing-casing annulus is of utmost importance. As noted above, the seal is typically set through the application of fluid pressure against a piston. The effectiveness of the seal is limited by the amount of fluid pressure that can be safely applied to the packer within the working string. Thus, a need exists for a packer which can be sealed by the direct application of mechanical force on the sealing element and against the casing, without the need of fluid pressure.

[0011] An additional limitation found within conventional packers, and as noted in the Arizmendi ('858) patent, is that the exterior sealing element travels on the packer exterior from the well surface to the downhole location. When the packer is run thousands of meters into a wellbore, the packing seal abrasively contacts the interior surface of the casing. In some instances, the packing seal may be worn away from the packer sleeve. This failure may not be detected until the packer is set and the pressure containment of the isolated zone fails. Thus, a need exists for a packer which has a sealing section with a smaller outer dimension that can be run into the wellbore and then expanded. In this manner, the sealing element can be lowered into the wellbore with less abrasion of the exterior sealing element against the inner wall of the casing.

[0012] An additional disadvantage to the conventional packer is the limited diameter of the bore provided through the packer body. Those of ordinary skill in the art will appreciate that the through-opening within the inner elongated hollow mandrel defines an opening which is somewhat smaller than the interior of the casing. This creates a limitation to the size and quantity of material that can be run into the wellbore. Thus, a need also exists for a packer which accommodates a larger string of tubing, multiple strings of larger tubing, or additional electronic feedthroughs by a larger through-opening.

[0013] Accordingly, a need exists for an expandable packer that avoids the disadvantages cited above, and provides a reliable seal with the casing in the wellbore.

[0014] It is, therefore, one of the many objects of the present invention to provide a novel packer having an expandable seating body which provides a more secure fluid seal, with the seal being created by the direct application of mechanical force to the seating element against the casing.

[0015] Still further, an object of the present invention is to provide a packer body which is seated onto a seating body after the seating body has been expanded and set within the casing. In this manner, a packer body having a larger through-opening may be utilized so as to accommodate additional or larger tools therethrough.

[0016] An additional object of the present invention is to provide a packer having a seating body which is dimensioned to reduce the risk of abrasion between the sealing element and the interior casing as the seating body is run into the wellbore.

[0017] Additional objects and advantages will become apparent from the detailed description of the invention, below.

[0018] The present invention provides an expandable packer, and a method for seating an expandable packer within a cased wellbore.

[0019] The apparatus of the present invention first comprises an expandable seating body. The seating body is tubular in configuration, and is run into a cased wellbore at the lower end of a string of tubulars. The seating body is releasably connected to an expander tool. At the appropriate depth, the expander tool is activated so as to expand a portion of the seating body into contact with the casing. The connection between the expander tool and the seating body is then released. The expander tool can then be reciprocated in a rotational and vertical fashion so as to expand the entire seating body into a frictional connection with the cemented casing.

[0020] After the seating body is expanded into position, the expander tool is removed from the wellbore. A packer body is then run into the hole where it is seated onto the seating body. The inner surface of the seating body is dimensioned to receive the packer body therein.

[0021] It is one purpose of the expandable packer to provide a fluid seal between the tubing-casing annulus within a wellbore. In this manner, zones within a wellbore can be isolated. To facilitate the isolation between zones, one or more sealing elements is provided on the outer surface of the seating body. This sealing element is circumferentially fitted onto the outer surface of the seating body. The sealing element makes contact with the casing when the seating body is expanded.

[0022] In addition, one or more packer seals is provided on the packer body. The packer seals are fitted around the outer surface of the packer body. Packer seals may include chevrons, o-rings, t-seals, or bonded rubber seals, and others, and are received within and make contact with the inner surface of the seating body when the packer body is landed into the seating body.

[0023] In one aspect, the inner surface of the seating body is profiled so as to receive dogs located on the outer surface of the packer body. This provides a means for landing the packer body within the seating body. This also facilitates the removal of the run-in string without also pulling the packer body. In this respect, a shearable or other releasable connection is employed between the run-in string and the packer body so as to allow the packer body to be released from the run-in string once the packer body is seated.

[0024] In one embodiment of the method of the present invention, the packer body is run into the wellbore along with the seating body and the expander tool in a single trip.

[0025] So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.

[0026] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

[0027] FIG. 1 is a front view of the seating body of the present invention, in contact with the inner wall of the casing of a wellbore.

[0028] FIG. 2 is a sectional view of a seating body of the present invention, in contact with the inner wall of the casing of a parent wellbore.

[0029] FIG. 3 is a perspective view of a seating body of the present invention, in phantom. The seating body is within a wellbore, and is releasably connected to an expander tool. In this view, the expander tool has not yet been activated to expand the seating body.

[0030] FIG. 4 is an exploded view of an expander tool as might be used to expand a seating body of the present invention.

[0031] FIG. 5 is a schematic view of the expander tool connected to the seating body of the present invention in a downhole position. A retractable collet is employed for a releasable connection between the expander tool and the seating body. In addition, a torque anchor is shown to stabilize the seating body during expansion.

[0032] FIG. 6 is a side view of the expander tool and seating body of FIG. 8, with the collet in its retracted position, and with the torque anchor in its set position.

[0033] FIG. 7 is a cross-sectional view of a torque anchor in its retracted position.

[0034] FIG. 8 is a perspective view of a packer body being run into a wellbore, and being positioned for seating into a seating body of the present invention. In this view, the seating body has been expanded into contact with the casing.

[0035] FIG. 9 is a schematic view of a packer body landed into a seating body of the present invention. In this embodiment, two strings of production tubing are placed through the packer body.

[0036] FIG. 10 is another schematic view of a packer body landed into a seating body of the present invention. In this embodiment, one string of production tubing is utilized, and two feed-through lines are set through the packer body.

[0037] FIG. 11 is a perspective view of a seating body of the present invention, in phantom, for setting in a single trip. The seating body is within a wellbore, and is releasably connected to an expander tool. Present also in the tubular string is a packer body. In this view, the expander tool has not yet been activated to expand the seating body.

[0038] FIG. 12 is a perspective view of a seating body of FIG. 11. In this view, the expander tool has been activated to expand the seating body.

[0039] FIG. 13 is a perspective view of a seating body of FIG. 12. In this view, the packer body has been landed into the seating body. The expander tool will remain in the wellbore below the packer body.

[0040] FIG. 1 is a schematic view of the front of the seating body 10sof the present invention. The seating body 10sdefines a tubular apparatus concentrically fitted within casing 40 of a wellbore. This necessarily means that the outer diameter of the seating body 10sis less than the inner diameter of the casing 40.

[0041] In order to fulfill the sealing function of the expandable packer 10 of the present invention, one or more sealing elements 16sare provided on the outer surface of the seating body 10s. This sealing element 16sis preferably an elastomeric material circumferentially fitted onto the outer surface of the seating body 10s. The sealing element 16smakes contact with the casing 40 when the seating body 10sis expanded. In FIG. 1, the sealing element 16sis shown to be expanded so that a fluid seal is established between the sealing element 16sand the casing 40.

[0042] The seating body 10soptionally includes slips 14 which engage the casing 40. In the preferred embodiment, a plurality of slips 14 are disposed along the outer surface of the seating body 10s. The slips 14 define buttons having teeth 15 for gripping the inner surface of the casing 40, thereby providing further friction between the seating body 10sand the casing 40. The slips 14 may be of any shape, and may even define a contiguous ring (not shown) around the outside surface of the seat 10. In one aspect, the teeth 15 of the slips 14 are fabricated from a carbide material. It is within the scope of this invention 10 to utilize slips of other forms and materials, such as an array of teeth (not shown) helically machined into the outer surface of the seat 10, or no slips at all.

[0043] FIG. 2 is a sectional view of a seating body 10sof the present invention. In both FIG. 1 and FIG. 2, the seating body 10sis shown to be expanded so that the slips 14 are in contact with the inner wall of the casing 40. Thus, a friction fit is established between the outer surface of the seating body 10sand the inner surface of the casing 40. The seating body 10sessentially defines an expandable body portion and a profile 13 therein for receiving another tool. Profile 13 is shown as a ring within the inner surface of the seating body 10sin FIG. 2.

[0044] The seating body 10sis designed to serve as a landing for a packer body 10p, shown in FIG. 8. To accomplish this purpose, the inner diameter of the seating body 10sis dimensioned to receive the packer body 10p. The inner surface of the seating body 10sis profiled so as to receive dogs 17 disposed along the outer surface of the packer body 10p. Dogs 17 are received within profile ring 13 of the seat 10s.

[0045] The seating body 10sis lowered into the wellbore 44 on a tubular string 42 such as jointed tubing or coiled tubing. FIG. 3 presents a seating body 10sof the present invention 10 positioned at the lower end of a working tubular 42. In this figure, the seating body 10sis presented in phantom.

[0046] FIG. 3 also presents an expander tool 20, to be used in expanding the seating body 10s. The expander tool 20 is more fully shown in FIG. 4, which is an exploded view of an exemplary expander tool 20. In one aspect, the expander tool 20 has a body 28 which is hollow and generally tubular with connectors 29 for connection to other components (not shown) of a downhole assembly. The connectors 29 are of a reduced diameter compared to the outside diameter of the longitudinally central body part 28 of the tool 20. The central body part 28 has three recesses 27 to hold a respective roller 22. Each of the recesses 27 has parallel sides and extends radially from a radially perforated tubular core (not shown) of the tool 20. Each of the mutually identical rollers 22 is somewhat cylindrical and barreled. Each of the rollers 22 is mounted by means of an axle 24 at each end of the respective roller and the axles are mounted in slidable pistons 26. The rollers 22 are arranged for rotation about a respective rotational axis which is parallel to the longitudinal axis of the tool 20 and radially offset therefrom at 120-degree mutual circumferential separations around the central body 28. The axles 24 are formed as integral end members of the rollers and the pistons 26 are radially slidable, one piston 26 being slidably sealed within each radially extended recess 27. The inner end of each piston 26 is exposed to the pressure of fluid within the hollow core of the tool 20 by way of the tubular 42. In this manner, pressurized fluid provided from the surface of the well, via the tubular 42, can actuate the pistons 26 and cause them to extend outward whereby the rollers 22 contact the inner surface of the seating body 10sto be expanded.

[0047] In the perspective view of FIG. 3, the expander tool 20 has not yet been activated to expand the seating body 10s. The expander tool 20 is held to the seating body 10sby at least one releasable connection 62. In one embodiment, the releasable connection is shearable, and defines a pin (not shown) connected to the seating body 10s, such as by welding. However, in the embodiment shown in FIG. 3, a collet 62 is utilized below the expander tool 20. The collet 62 is affixed to a nipple 60, as shown in FIGS. 5 and 6. In one embodiment, shown in the perspective view of FIG. 8, the collet 62 is an elastomeric ring which encircles the nipple 60, and resides in a collet profile 64 formed within the inner surface of the seat 10s. This arrangement provides more secure support for the seating body 10son the expander tool 20 as it is run into the hole 44. Those of ordinary skill in the art will appreciate that a shearable pin could become sheared while the expander tool 20 is being run into the wellbore 44, causing the seat 10sto fall to the bottom of the wellbore 44. A swivel 56 allows the expander tool 20 to rotate while the collet 62 continues to engage and support the seat 10.

[0048] The nipple 60 includes a nozzle 66. The nozzle 66 serves as an outlet through which fluid may be circulated. The nozzle 66 defines a sized orifice by which pumped fluid can reach critical flow. Once critical flow is reached, pressure builds within the expander tool 20 for activation of the rollers 22.

[0049] At the appropriate depth, and while the collet 62 continues to support the seat 10, the expander tool 20 is activated so as to expand a portion of the seating body 10sinto contact with the casing 40. The expander tool 20 is then rotated so as to release the connection between the expander tool 20 and the seat 10s, and to create complete radial contact between a portion of the seat 10 and the casing 40. Expansion of a portion of the casing 40 at the initial depth of the expander tool 20 will cause the seat 10sto release the collet 62, such that the collet 62 is no longer affixed within the collet profile 64. The expander tool 20 can then be reciprocated in both a rotational and vertical fashion so as to expand the entire seat 10 into a frictional connection with the cemented casing 40.

[0050] It is within the scope of the invention to provide a collet 62 which is capable of being mechanically retracted from the collet profile 64. In this respect, the collet 62 would be released via mechanical switch, or via release of pressure from a fluid line, or other means (not shown) known in the art for releasing a collet 62. Thus, the collet 62 would be retracted from the collet profile 64 at the time an initial portion of the seat 10sis expanded into contact with the inner surface of the casing 40.

[0051] It is further within the scope of this invention to provide a shear pin or other releasable connection (not shown) between the expander tool 20 and the seat 10 in lieu of or in addition to a collet. Where a shearable pin is used, rotation of the expander tool 20 serves to release the connection between the expander tool 20 and the seat 10. The expander tool 20 is also reciprocated in a rotational and vertical fashion so as to expand the entire seat 10 into a frictional connection with the cemented casing 40.

[0052] As a further aid in the expansion of the seating body 10s, a torque anchor 50 may be utilized. The torque anchor 50 is designed to prevent the seat 10 from rotating while the expander tool 20 acts against the seat 10s. The torque anchor 50 defines a body having sets of wheels 54cand 54sradially disposed around its perimeter. The wheels 54cand 54sreside within wheel housings 53, and are oriented to permit axial (vertical) movement, but not radial movement, of the torque anchor 50. Sharp edges (not shown) along the wheels 54cand 54said in inhibiting radial movement of the torque anchor 50. In the preferred embodiment, four sets of wheels 54cand 54sare employed to act against the casing 40 and the seating body 10s, respectively.

[0053] The torque anchor 50 is run into the wellbore 44 on the working string 42 along with the expander tool 20 and the seating body 10s. The run-in position of the torque member 50 is shown in FIG. 5. In this position, the wheel housings 53 are maintained essentially within the torque anchor body 50. Once the seating body 10sis lowered to the appropriate depth within the wellbore 44 and oriented, the torque anchor 50 is activated. Fluid pressure provided from the surface through the working tubular 42 acts against the wheel housings 53 to force the wheels 54cand 54sfrom the torque anchor body 50. Wheels 54cact against the inner surface of the casing 40, while wheels 54sact against the inner surface of the seat 10. This activated position is depicted in FIG. 6.

[0054] FIG. 7 presents a cut-away view of the torque anchor 50. The extended position of the wheels 54cand 54sis shown in phantom. Visible within the cut-away is a rotating sleeve 51 which resides longitudinally within the torque anchor 50. The sleeve 51 rotates independent of the torque anchor body 50. Rotation is imparted by the working tubular 42. In turn, the sleeve 51 provides the rotational force to rotate the expander tool 20.

[0055] An annular space 55 exists between the sleeve 51 and the wheel housings 53. Through-openings 58 reside within the sleeve 51 which allow fluid to enter the annular space 55 and act against the wheel housings 54. The wheel housings 53, in turn, extrude from the torque anchor body 50 and grip the casing 40 and seat 10, respectively, to prevent rotation during initial expansion of the seating body 10s. It will be appreciated that the initial vertical movement of the expander tool 20 will need to be upward. This is because the size of the torque anchor 50 will prevent the expander tool 20 from moving downward until after the upper portions of the seat 10 have been expanded. As the expander tool 20 is raised, the seat wheels 54son the torque anchor 50 clear the top of the seat 10. By that time, however, the seating body 10sis sufficiently expanded to prevent rotation with the expander tool 20. Once the upper portions of the seat 10shave been expanded, the expander tool 20 is lowered so that the lower portions of the seat 10scan also be expanded.

[0056] After the seating body 10shas been completely expanded into frictional contact with the inner wall of the casing 40, the expander tool 20 is deactivated. In this regard, fluid pressure supplied to the pistons 26 is reduced or released, allowing the pistons 26 to return to the recesses 27 within the central body part 28 of the tool 20. The expander tool 20 can then be withdrawn from the wellbore 44 by pulling the working tubular 42. The wellbore 44 is then ready to receive the packer body 10p.

[0057] After the seat 10sis expanded along its length, a packer body 10pis run into the wellbore 44. FIG. 8 is a perspective view of a packer body 10pbeing run into a wellbore 44, and being positioned for seating into a seating body 10sof the present invention. In this view, the seating body 10shas been expanded into contact with the casing 40. In the preferred embodiment, the packer body 10pis a resilient member such as, for example, of a steel or composite construction. In the preferred embodiment, the packer body 10pincludes an elongated tubular inner mandrel defining a polished inner bore 11.

[0058] The packer body 10pis run into the wellbore 44 on a tubular 42. The tubular 42 again may be a jointed tubing or coiled tubing or other working string. Typically, the run-in tubular for the packer body 10pis the production tubing, shown as 42 in FIG. 8 and as 42′ in FIGS. 9 and 10. The packer body 10phas a top end 18 and a bottom end 19. At least the top end 18 is connected to the tubular 42. As shown in the embodiment of FIG. 8, the packer body 10pis in series with the production tubular 42 such that the tubular 42 is connected to the packer body 10pat both the top 18 and bottom 19 ends of the packer body 10p. In this embodiment, the tubular string 42 and the inner bore 11 are in fluid communication.

[0059] As the packer body 10pis lowered into the wellbore 44, the packer body 10pcomes into contact with the positioned seat 10s. The lower end 19 of the packer body 10pmay optionally be beveled, as shown in FIG. 8, to aid the landing of the packer body 10pinto the seating body 10s. As noted in connection with FIG. 2, the inner surface of the seating body 10sis profiled 13 so as to receive dogs 17 located on the outer surface of the packer body 10p. Dogs 17 are configured to land in profile ring 13 within the inner surface of the seating body 10s. The dogs 17 are biased to extend outward from the seating body 10s, but are capable of retracting to a first recessed position along the plane of the seating body 10swhen the dogs 17 come into contact with the profile 13. In this manner, the dogs 17 will recess upon contact with top end 12, but then pop into place within the profile 13 once the packer body 10plands fully into the seating body 10s. This provides a means for landing the packer body 10pwithin the seating body 10s.

[0060] An additional feature of the packer body 10pof the present invention is the use of one or more packer seal members 16p. One seal member 16pis depicted the perspective view of FIG. 8. The seal member 16pis circumferentially attached to the packer body 10palong its outer surface, thereby providing a fluid seal between the packer body 10pand the seating body 10safter the packer body 10phas been landed into the seat 10s. The packer seal members 16pare preferably fabricated from an elastomeric or other suitable material to facilitate the fluid seal with the seating body 10s. Packer seals 16pmay include chevrons, O-rings, t-seals, bonded rubber seals, and others types of seals. At least a portion of the inner surface of the seating body 10swill be polished to facilitate a sealed connection with the packer sealing elements 16p.

[0061] FIG. 9 is a schematic view of a packer body 10planded into a seating body 10sof the present invention. Typically, the packer body 10pis made up with the production tubing 42′ and run into the wellbore 44. In the embodiment shown in FIG. 9, two strings of production tubing 42′ are placed through the packer body 10p. The packer body 10pis then run into the wellbore 44 and landed onto the seat 10s.

[0062] FIG. 10 is another schematic view of a packer body 10planded into a seating body 10sof the present invention. In this embodiment, one string of production tubing 42′ is utilized, and two feed-through lines 43 are set through the packer body 10p. FIGS. 9 and 10 demonstrate that the expandable packer apparatus 10 of the present invention provides a greater proportion of useable diameter for running downhole tubulars than the conventional packer.

[0063] As the foregoing demonstrates, the present invention provides a novel, expandable seating body 10sfor landing a packer body 10p. A novel method for seating a packer is also disclosed. In this respect, an expandable seat 10sis run into a cased wellbore 44. The seat 10 in one aspect is lowered into the wellbore 44 at a desired depth, along with an expander tool 20. The expander tool 20 is activated so as to expand the seat 10salong its entire longitudinal length. The seat 10sis thereby frictionally set within the inner surface of the casing 40. The expander tool 20 is removed from the wellbore 44, and a packer body 10pis then lowered therein. As the packer body 10pis run into the hole 44, it enters the seating body 10s. Dogs 17 disposed around the outer surface of the packer body 10pland in a profile ring 13 provided within the inner surface of the seating body 10s.

[0064] In another embodiment of an expandable packer, and method for seating a packer, an expandable seating body 10sis lowered into the wellbore 44, releasably connected to an expander tool 20. Above the expander tool 20, and within the same working string 42, is a packer body 10p. This arrangement is shown in FIG. 11. In this view, the expander tool 20 has not yet been activated to expand the seating body 10s.

[0065] The expander tool 20 acts to expand the seating body 10sin accordance with the methods disclosed above. The working string 42 or, optionally, production tubing 42′ is then lowered further into the wellbore 44 with the expander tool 20 still attached. This step is demonstrated in the perspective view of FIG. 12.

[0066] As shown in FIG. 13, the packer body 10pis lowered into the wellbore 44 until the packer body 10plands into the seating body 10s. The expander tool will remain in the wellbore 44 below the packer body 10p.