Not Applicable.
Not Applicable.
The present invention relates to tools for use in well drilling operations. More specifically, the present invention relates to an anchor for securing a tool within a well bore.
Many operations performed in the course of exploration and production of oil and gas require that axial forces be applied to tools and other devices inside of a wellbore. In many instances the tool must be supported at a specific location inside the wellbore with an anchoring device. Downhole tool anchors and other isolation devices, comprising packers and plugs, have been extensively utilized in the industry. An exemplary application for an anchor involves a whipstock to be installed in a wellbore to facilitate drilling of additional wellbores in different directions off of the original or primary wellbore.
“Dog” anchoring devices extend from within the envelope of the body of a tool into a pre-installed channel placed along the completion string within the wellbore. These types of anchors can withstand large forces, but require anchoring grooves at predetermined locations along the completion string. “Slip” anchors apply an anchoring force against the wellbore by extending small gripping plates, commonly known as slips, to the side of the surrounding wellbore.
Other anchoring devices utilize pistons or rams which can be moved radially outward from the tool body to engage the circumference of a wellbore. Still other systems employ linkage systems to expand against a wellbore surface. Other types of anchors use fluid to lift anchoring surfaces which move vertically along a track or rail system. Other anchor types require an expansion or explosion of combustible materials to generate the required pressure to expand the anchoring surfaces against the side of the wellbore.
Whipstocks are used to drill additional multi-directional wellbores from a primary wellbore. A whipstock is a long steel casing which contains an inclined plane to cause the drill bit to deflect from the original wellbore at an angle. It is often necessary that an anchor be placed to securely hold the whipstock in place.
Prior art anchoring devices comprise, but are not limited to, the following:
U.S. Pat. No. 4,153,109 discloses an anchor having annular slip sections for engaging a casing. Upper and lower expanders have frustoconical shaped ends to engage the slip structures.
U.S. Application No. 20090071659 filed by Spencer, et al, published Mar. 19, 2009, discloses a technique for anchoring a tool in a wellbore. The technique utilizes one or more arms pivotally mounted to a structure for movement between a radially inward position and radially outward position that anchors the tool to a surrounding wall. A wedge component is positioned to selectively engage the arms.
U.S. Pat. No. 5,350,016 issued to Thornton, Jr. on Sep. 27, 1994 discloses a wellbore anchor tool which employs at least one pair of individual slip segments which wrap at least partially around a mandrel passing through the tool, the individual slip segments carrying bearing surfaces and restraint members for holding the slip segments in the tool but at the same time in slidable engagement with the tool.
U.S. Pat. No. 6,035,939 issued to Carter on Mar. 14, 2000 discloses a whipstock system having an anchor apparatus, the anchor apparatus incorporating a slip having an inclined surface and a toothed engaging surface for engaging a casing.
U.S. Pat. No. 5,154,231 issued to Bailey, et al on Oct. 13, 1992 discloses a one-trip whipstock assembly incorporating a hydraulically set anchor which comprises an interlock for maintaining the anchor in its set position. An anchor is connected to the lower end of the assembly. Slip elements are expanded outwardly in response to the fluid pressure to engage the casing and set the anchor.
U.S. Pat. No. 5,878,818 issued to Hebert, et al on Mar. 9, 1999 discloses a mechanically set anchor wherein a plunger extending from a base end of an anchor body activates a pin type trigger which releases a spring utilized to set multiple slips extending from the body of the anchor. Continued downward compressive forces fully set the slips into the borehole pipe casing. The anchor is mechanically released by upward pull to shear release pins.
U.S. Pat. No. 5,829,531 issued to Hebert, et al on Nov. 3, 1998 discloses a mechanically set anchor, commonly used with a whipstock assembly, wherein a plunger extending from a base end of an anchor body activates a pin type trigger which releases a spring utilized to set multiple slips extending from the body of the anchor.
U.S. Pat. No. 5,350,016 issued to Thornton, Jr. on Sep. 27, 1994 discloses downhole anchor tools. Individual slip segments are mounted about a mandrel with sloping surfaces engaging a sloping drive surface.
U.S. Pat. No. 7,086,462 issued to Rutley, et al on Aug. 8, 2006 discloses an anchor assembly. Upper frictional members are spring-tensioned. Lower frictional engagement members slide along a conical engagement surface causing the lower frictional members to extend outwardly and engage the inner surface of the casing.
U.S. Pat. No. 6,920,927 issued to Hirth on Jul. 26, 2005 discloses a wellbore anchoring device for anchoring a down-hole tool comprising an expandable cone having an annular integral shoulder, defining the large end of a conical annular recess on an outer surface of the cone, and a resilient slip positioned within the annular recess. Axial travel of the slip is limited by engagement with the shoulder.
U.S. Pat. No. 7,431,080 issued to Wright, et al. on Oct. 7, 2008 discloses an anchor having slips at one end and a tapered opposite end for mating with a slip cone. The slip assembly 40 is slidingly connected to the mandrel outer surface and travels along this surface to the slip cone for actuation. A pin travels along a pattern on outer surface of the mandrel to advance the slip assembly and to retract the slip assembly.
U.S. Pat. No. 7,588,078 issued to O'Brien on Sep. 15, 2009 discloses an anchor having ramps that extend through apertures in slip structures giving the slips a ramp to ride out in a radial direction.
U.S. Pat. Nos. 7,178,589, 7,377,328 and 7,448,446 to all disclose slips having angled extensions along the sides of the slips extending at an angle to the backs of the slips. Extensions fit within corresponding channels in recesses of the slip housings.
An anchor for securing a tool within a well bore comprises a plurality of slips connected to an anchor body, each slip hingedly connected to a link at a first end and each slip slidably retained in an anchor body channel at a second end, the slip connection arm hingedly connected to the anchor body. A piston contained within an annular opening is axially moveable on a mandrel toward the slips to force slips outward to engage a surrounding surface of a wellbore or casing. Inclined guide surfaces facilitate slip extension. Upon slip extension, slips are held in fixed orientation by the links and channels provided in the anchor.
In some embodiments, an anchor tool includes a body, a plurality of slips coupled to the body, each slip hingedly coupled to a link at a first end, each slip slidably retained in a channel at a second end, each slip operably moveable from a retracted orientation to an expanded orientation. The link may be coupled to and selectively received within a complementary link recess of the body. The slip may be selectively at least partially received within a complementary slip recess of the body. The anchor tool may further comprise a mandrel coupled to the body and extending from the body, and a cap coaxially aligned with the mandrel and having an inclined surface to engage an inclined inner surface of each slip. The cap may be slidably received on the mandrel such that the inclined surface engages each slip inclined surface between the retracted and expanded orientations. Each link may hingedly couple each slip to the body between the retracted and expanded orientations. The cap may be movable in response to application of a fluid pressure to an exterior of the mandrel. In response to moving the cap toward the body, each slip may move between the retracted orientation and the expanded orientation.
In some embodiments, an anchor tool includes a body including an outer diameter, the body being substantially coaxially aligned with a central axis of the anchor tool, a link coupled to the body, the link being both retractable relative to the body and rotatable relative to the body, a cap comprising an inclined surface, the cap being coaxially aligned with the central axis, and a slip, the slip being rotatably coupled to the link and the slip comprising an inclined surface configured for selective sliding engagement with the inclined surface of the cap. The link may be selectively received within a complementary link recess of the body. The slip may be selectively at least partially received within a complementary slip recess of the body. The anchor tool may further comprise a mandrel, the mandrel being rigidly coupled to the body and the mandrel being slidably received through the cap. The cap may be movable in response to increasing a fluid pressure supplied to the anchor tool. The cap may be movable in response to application of a fluid pressure to an exterior of the mandrel. In response to moving the cap, the slip may be moved radially relative to the central axis. The slip may be substantially prevented from rotating relative to the central axis. The mandrel may comprise a central passage and an associated flow orifice for receiving fluid.
In some embodiments, an anchor tool includes a body including an outer diameter and a recess, a link pivotally coupled to the body in the recess and below the outer diameter, a slip pivotally coupled to the link, the slip comprising an engagement surface, and a cap moveably coupled to the body, wherein the slip is captured between the body and the cap, the cap moveable to engage a cap engagement surface with the slip engagement surface. The link may be translatable relative to the body.
In some embodiments, a method of operating an anchor tool includes locating the anchor in a well bore, altering a fluid pressure supplied to the anchor tool, moving a cap of the anchor tool toward a body of the anchor tool, wherein a slip of the anchor tool is connected to the body via a rotatable link and wherein the cap includes an inclined surface, and in response to moving the cap toward the body, radially moving the slip relative to the central axis while substantially preventing rotation of the slip relative to the central axis.
Referring now to the figures, wherein like elements are numbered alike in the several drawings:
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Body 40 is attached at its lower end 47 to upper mandrel 24. In the embodiment depicted, body 40 is attached by threading to upper mandrel 24. Upper mandrel 24 is a tubular structure coaxially aligned with body 40. Upper mandrel 24 has a central passage 48 extending therethrough. Central passage 48 is aligned with passage 42 of body 40.
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The exterior surface of the cylinder cap 38 comprises a guide surface 90. Each guide surface 90 is sized and positioned for sliding engagement with lower guide surface 66 of slip 28. Each of lower guide surface 66 and guide surface 90 are inclined at angle to axis 100. In the embodiment illustrated guide surface 90 extends at a 150 degree angle to axis 100 and slip lower guide surface extends at a 30 degree angle to axis 100 (in relation to the y axis of an x-y grid with the axis 100 corresponding to y), but the angle may be different in alternative embodiments.
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A flow orifice 106 is provided in upper mandrel 24. Flow orifice 106 is sized and positioned to allow flow of fluid from passage 48 into annular opening 104. Connector 52 comprises connector flange 111. Connector flange 111 sealingly engages lower housing 102. Piston head 94 sealingly engages lower housing 102. Accordingly, fluid transmitted from passage 48 into annular opening 104 is retained intermediate connector flange 111 and piston head 94.
Anchor 10 components are sized and structured such that fluid flow into annular opening 104 first fills annular opening 104 with fluid (not shown), then biases piston head 94 upward toward body 40. As cylinder 32 and cylinder cap 38 are each slidable on upper mandrel 26, continued injection of fluid into annular opening 104 pushes all of piston 30, cylinder 32, and cylinder cap 38 upward toward body 40. Such force causes slips 28 to extend outwardly. Interaction of inclined slip upper guide surface 64 with body guide surface 84 facilitates outward movement of slip 28 at slip 28 upper end 70. Interaction of inclined slip lower guide surface 66 with each cylinder cap inclined surface 90 facilitates outward movement of each slip 28 at the slip lower end. In some embodiments, the outward extension of slips 28 occurs without rotating the slips 28 relative to the central axis 100.
When sufficient fluid is introduced into annular opening 104, slips 28 will be extended until exterior surfaces 60 of slips 28 engage casing wall 58 or portions of an uncased bore, anchor 10 will be set in a fixed position in relation to casing wall 58 or an uncased bore.
Hinged link 34 retains slip 28 in its radially extended orientation at slip upper end 70. Channels 88 provided in upper casing 110 retain the lower end of each slip 28 in its radial orientation at the slip lower end. Additionally, the links 34 and channels 88 provide rotational and/or angular stability to the slips 28 relative to the central axis 100.
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To pull the anchor 10 from its locked position within the casing 58, it is necessary to exert upward tension on mandrels 24 and 26 until shear pins 118 are severed from shear sleeve 122. Upon such severance, housing 102 will be free to slide in relation to mandrel 26, allowing piston 30 to drop along the upper mandrel 24 and to allow slips 28 and links 34 to retract back within the tool, and in some embodiments, radially inward beneath an outermost diameter of the body 40.
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In the mostly and/or fully retracted state, in some embodiments, the exterior surface 60 of slips 28 may either collectively form an outer diameter substantially similar to or less than an outer diameter of the body 40 and/or the remainder of subassembly 22. In other words, in some embodiments, the slips 28 may be configured not to protrude radially outward more than a remainder of the subassembly 22 when the slips 28 are in a mostly and/or fully retracted state. As such, the slips 28 may be less likely to present surfaces and/or edges that may undesirably catch or hang on casing 58 features and/or debris within casing 58 and/or an uncased bore. Once the anchor tool 10 is at its desired depth and/or location within the casing 58 and/or bore, fluid pressure may be applied to the anchor tool 10.
As fluid pressure is increased and as the annular opening 104 is increasingly filled with fluid, the piston 30 may be forced to move along the length of the upper mandrel 24. With sufficient movement of the piston 30 and its associated cylinder 32 and cylinder cap 38, the inclined guide surface 90 of the cylinder cap 38 may contact the complementary inclined lower guide surfaces 66 of the slips 28. With continued movement of the cylinder cap 38 toward the body 40, the slips are increasingly forced radially outward away from the central axis 100. Even when slips 28 are significantly extended radially outward away from the central axis 100, and in some embodiments so far as to contact casing 58, anchor tool 10 is configured to ensure that the slips 28 are robust and resistant to any angular rotation of the anchor tool 10 about the central axis 100.
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At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to comprise iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 comprises, 2, 3, 4, etc.; greater than 0.10 comprises 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, RI, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=RI+k*(Ru−RI), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, comprises, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope comprising all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. Further, while the claims herein are provided as comprising specific dependencies, it is contemplated that any claims may depend from any other claims and that to the extent that any alternative embodiments may result from combining, integrating, and/or omitting features of the various claims and/or changing dependencies of claims, any such alternative embodiments and their equivalents are also within the scope of the disclosure.
Number | Date | Country | |
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61388508 | Sep 2010 | US |