EXPANDABLE SPIRAL THREADED APPARATUS AND METHOD FOR ANCHORING A DOWNHOLE TOOL TO A CASING, AND METHOD FOR ASSEMBLING THE APPARATUS

CROSS-REFERENCE TO RELATED APPLICATIONS

See Application Data Sheet.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

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INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

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STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR

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BACKGROUND OF THE INVENTION
1. Field of the Invention

The present invention relates to isolating zones in a wellbore. More particularly, the present invention relates an anchoring component of a downhole tool to a casing. The downhole tool, such as a plug or packer, isolates a zone in the wellbore. Even more particularly, the present invention relates to an expandable spiral threaded anchoring component.

2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98

A slip is a basic anchoring component to hold a downhole tool 1 at a desired location in the borehole, as shown in FIG. 1. The basic anchoring component includes a slip 2 and cone 3. The cone 3 is pushed into the slip 2, which fractures while expanding radially outward to contact the casing 4 or tubing in the borehole. The textured outer surface of the slip 2 grips the casing 4 to prevent movement. FIG. 2 shows the basic anchoring component in the context of a downhole tool 1. FIG. 2 shows a conventional plug or packer with two slips 2, indicating that the downhole tool 1 has two anchoring components. With two slips 2, one in each direction, the downhole tool 1 resists movement within the casing 4 in both directions. Characteristics of an anchoring component, including slip geometry, ramp style, ramp geometry, and tooth style, are known to affect the properties of the anchoring component. The angled surfaces on slips and cones work using the principles of an inclined plane. The anchoring component functions as a force amplifier due to the mechanical advantage provided by the ramps. An applied axial force (input force) is converted to a larger radial force (output force). The high output force allows the slip to expand and bite into the casing or tubing.

A barrel slip 8 is a particular type of slip of an anchoring component that resists movement in both directions, as shown in FIG. 3. The geometry, ramp style, ramp geometry, and tooth style can also be modified for a barrel slip 8. Instead of needing a complementary slip for resisting movement in each direction along the casing, a barrel slip 8 can hold the downhole tool in both directions. FIGS. 4-6 show a prior art barrel anchoring component 5 of a downhole tool. The barrel anchoring component 5 comprises the barrel slip 8, a first straight threaded cone 6, a second straight threaded cone 7, and a mandrel 9. The sectional views of FIGS. 5-6 show multiple inclined surfaces interacting between the barrel slip 8 and the first straight threaded cone 6 and between the barrel slip 8 and the second straight threaded cone 7. FIG. 5 shows the run-in configuration with the smaller diameter of the component 5 and the threads of the barrel slip 8 friction fit between respective threads of the straight threaded cones 6, 7. FIG. 6 shows the expanded configuration with the larger diameter of the component 5 and the threads of the barrel slip 8 pushed outward along the incline angle of the threads of the straight threaded cones 6, 7. In the larger diameter of FIG. 6, the component 5 engages the casing or tubing within the borehole for locking the downhole tool in place. Like stacked cones, instead of a single conical surface, the barrel slip 8, the first straight threaded cone 6, and the second straight threaded cone 7 are in ratchet engagement. Force is used to push the first straight threaded cone 6 in one direction along the mandrel 9 and to push the second straight threaded cone 7 in an opposite direction along the mandrel 9 so that the first straight threaded cone 6 and the second straight threaded cone 7 are closer together. The multiple inclined surfaces of the threaded surfaces pushing against each other expand the barrel slip 8 to set the downhole tool in the casing or tubing.

There are various patents and patent publications disclosing anchoring components of a downhole tool, including barrel slips.

U.S. Pat. No. 5,944,102, issued on 31 Aug. 1999 to Kilgore et al, U.S. Pat. No. 5,906,240, issued on 25 May 1999 to Kilgore et al, U.S. Pat. No. 6,378,606, issued on 30 Apr. 2002 to Swor et al, and U.S. Pat. No. 6,481,497, issued on 19 Nov. 2002 to Swor et al, all disclose the prior art straight threaded barrel slip with ratchet engagement to opposing straight threaded cones. The various locking features or shear points of this barrel slip are connectors that still break apart as the barrel slip expands. The assembling and disassembling both require the snap-fit engagement that risks damage and deformation to the tight tolerances between the multiple inclined surfaces of the ramps and threads.

U.S. Pat. No. 11,441,371, issued on 13 Sep. 2022 to Fripp et al, and US Publication No. 2017/0145780, published on 25 May 2017 for Castro et al, disclose barrel slips with different components, such as sleeves and rings, for expansion, instead of cones.

One problem with the current barrel slip is the assembling and dissembling of the barrel anchoring component. The convention assembling method requires a press to install the barrel slip onto the straight threaded cones. Furthermore, the barrel slip is at least partially expanded over the threaded cone ramps during assembly using the press. Thus, there is a risk of permanently deforming the barrel slip or damaging the barrel slip during the assembling with the press. Additionally, for disassembling from the expanded configuration, the current barrel slip is almost impossible to release from the casing or tubing for disassembling without destroying the barrel slip. If one cone is not installed correctly, the current barrel slip cannot be removed without damaging the current barrel slip itself. The assembling is difficult because the ratchet engagement between the barrel slip and the threaded cones is a force-fit relationship. The barrel slip or the cones are deformed or at least distended to even assemble the tool, so there is weakening during assembly.

Another problem with the current barrel slip is precision tolerance. The ramp and slope engagements of the multiple inclined surfaces on both the barrel slip and each of the threaded cones must be very close in order to hold the expanded position of the barrel slip. The current barrel slip is very difficult to machine due to the extremely tight tolerance requirement. Tight tolerancing of linear dimensions is necessary to ensure proper timing and engagement of the inclined surfaces of the barrel slip and threaded cones. That is, the corresponding ramp pairs need to all contact as close to the same time as possible to ensure that the load is evenly distributed around each thread of the cone and each respective ramp of the barrel slip. The barrel slip is easily unbalanced with chips and gaps between the inclined surfaces of the current barrel slip and threaded cones. In practice, this level of precision machining leads to high manufacturing costs and very high scrap rates due to deviations. It also is a burden to quality control and engineering groups to address and disposition non-conforming parts.

As a result of the ratchet engagement with tight tolerance of the current barrel slip, the load capacity of the anchoring component is limited. The distribution of the load in use is defined by the contact area between the barrel slip and threaded cones. In the straight threaded cones, the contact area remains constant around the mandrel.

There are also various patents and patent publications disclosing spiral threaded surfaces, instead of straight threaded surfaces. The prior art spiral threads are on various components of the downhole tool, although not on the anchoring component of the downhole tool. U.S. Pat. No. 8,002,045, issued on 23 Aug. 2011 to Ezell et al, shows another downhole tool with threaded surfaces for expanding slips. The ratchet or coaxial threads are disclosed as interchangeable with spiral or helical threads. U.S. Pat. No. 4,494,777, issued on 22 Jan. 1985 to Duret, describes spiral threaded pipe joints between tubular members in a drill string. US Publication No. 2019/0234177, published on 1 Aug. 2019 for Silva et al, shows other spiral or angular threaded surfaces in a downhole tool. The consequences of spiral threads for assembling and disassembling and the consequences of increased force needed to separate spiral threaded surfaces are known in the prior art.

Variations on the placement and orientation of spiral threads on different components of a downhole tool are also known. Chinese Patent No. CN109973043, published on 5 Jul. 2019 for Guo, Dajin et al, and U.S. Pat. No. 3,472,520, issued on 14 Oct. 1969 to Burns, disclose spiral threads in different orientations and on different components, not the anchoring components of the downhole tool. Ratchet engagement of straight threaded surfaces on non-anchoring components of the downhole tool are disclosed in U.S. Pat. No. 3,584,684, issued on 15 Jun. 1971 to Anderson et al, U.S. Pat. No. 4,156,460, issued on 29 May 1979 to Crow, and U.S. Pat. No. 5,101,897, issued on 7 Apr. 1992 to Leismer et al.

It is an object of the present invention to provide an apparatus for anchoring a downhole tool to a casing or tubing within a borehole.

It is an object of the present invention to provide a spiral threaded apparatus for anchoring a downhole tool to a casing or tubing within a borehole.

It is an object of the present invention to provide a method for anchoring a downhole tool to a casing or tubing by expanding a spiral threaded barrel slip by pushing respective cones closer to each other within the barrel slip.

It is another object of the present invention to provide a barrel slip with a spiral threaded inner slip surface and a cone with a spiral threaded outer cone surface for anchoring a downhole tool to a casing or tubing within a borehole.

It is still another object of the present invention to provide a barrel slip with spiral threaded inner slip surfaces in opposing spiral directions and cones with corresponding spiral threaded outer cone surfaces for each spiral direction to anchor a downhole tool to a casing or tubing.

It is yet another object of the present invention to provide a barrel slip with spiral threaded inner slip surfaces in opposing spiral directions and cones with corresponding spiral threaded outer cone surfaces for each spiral direction locked in a run-in configuration until placed at the correction location in the casing or tubing.

It is yet another object of the present invention to provide a barrel slip with spiral threaded inner slip surfaces in opposing spiral directions and cones with corresponding spiral threaded outer cone surfaces for each spiral direction locked in an expanded configuration by preventing rotation of the barrel slip relative to the cones.

It is an object of the present invention to provide a method of assembling a spiral threaded apparatus for anchoring a downhole tool to a casing or tubing with reduced risk of deformation and damage to the components.

It is an object of the present invention to provide a spiral threaded apparatus for anchoring a downhole tool to a casing or tubing with greater precision tolerance between spiral threaded surfaces of the barrel slip and cones.

It is an object of the present invention to provide a spiral threaded apparatus for anchoring a downhole tool to a casing or tubing with greater distribution of load capacity.

These and other objectives and advantages of the present invention will become apparent from a reading of the attached specification, drawings and claims.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention include an apparatus for anchoring a downhole tool to a casing within a borehole, including a first cone, a second cone, and a slip device. The downhole tool can be a packer or plug or other tool that requires attachment to the casing or tubing in the borehole. The apparatus for anchoring is only one component of the downhole tool, which may include other components, such as sealing members, support rings, ball seats, and others, according to the functionality of the particular type of downhole tool.

The first cone has a first spiral threaded outer cone surface, being threaded in a first spiral direction. The second cone has a second spiral threaded outer cone surface, being threaded in a second spiral direction. The first cone is oriented towards or faces the second cone. The first cone is moveable towards the second cone within the slip device. Furthermore, the first spiral direction is opposite the second spiral direction. The first cone must be screwed into the slip device by rotating in one spiral direction, and the second cone must be screwed into the slip device by rotating in the opposite spiral direction.

The slip device can be a type of barrel slip with an outer slip surface and an inner slip surface. The outer slip surface can have a gripping means for the casing. The gripping means can be any known means for gripping, such as a toothed surface, a textured surface, an adhesive, and protrusions. The inner slip surface is divided into a first spiral threaded inner slip surface and a second spiral threaded inner slip surface. The first spiral threaded inner slip surface is in removable engagement with the first spiral threaded outer cone surface of the first cone with a spiral direction compatible with the first spiral direction of the first spiral threaded outer cone surface. The second spiral threaded inner slip surface is in removable engagement with the second spiral threaded outer cone surface of the second cone with a spiral direction compatible with the second spiral direction of the second spiral threaded outer cone surface.

The slip device has a run-in configuration with an initial diameter compatible with deploying the downhole tool through the casing or tubing to the downhole location. In the run-in configuration, there is spiral threaded engagement between the first spiral threaded inner slip surface and the first spiral threaded outer cone surface, and between the second spiral threaded inner slip surface and the second spiral threaded outer cone surface. The first cone is also positioned at an initial distance from the second cone within the slip device in the run-in configuration.

The slip device has a set configuration with an extended diameter compatible with anchoring to the case at the downhole location. In the set configuration, there is raised spiral threaded engagement between the first spiral threaded inner slip surface and the first spiral threaded outer cone surface, and between the second spiral threaded inner slip surface and the second spiral threaded outer cone surface. The first cone is also positioned closer to the second cone than the initial distance within the slip device in the set configuration. The extended diameter is greater than the initial diameter and large enough to anchor the slip device to the casing by the outer slip surface.

Other embodiments of the apparatus for anchoring include various locking devices to premature expansion of the slip device and to prevent unscrewing of the cones from the slip device. There is a lock to hold the initial distance between the first cone and the second cone in the run-in configuration of the slip device. There is another lock to prevent the slip device as a barrel slip with ribs from prematurely expanding to the extended diameter for the set configuration. There is still another lock to prevent rotation of the slip device as a barrel slip with ribs from reversing rotation of the first cone and the second cone so that the cones are not accidentally released from the slip device.

The present invention further includes a method for assembling the apparatus for anchoring the downhole tool. The method includes the step of inserting the first cone into the slip device in a spiral threaded engagement and the step of inserting the second cone into the slip device in a spiral threaded engagement opposite the first cone. The steps of inserting can be comprised of rotating the first cone in a first spiral direction and rotating the second cone in a second (and opposite) spiral direction. The apparatus is assembled into the run-in configuration with the slip device at the initial diameter and the first cone at the initial distance to the second cone. The method for assembling further includes the steps of installing the various locking devices on the apparatus in the run-in configuration, after the cones are inserted.

Embodiments of the method of the present invention includes the method of using the apparatus to anchor to a casing within a borehole. The method for anchoring includes deploying the downhole tool with the apparatus having the slip device in the run-in configuration into the casing. The method also includes the step of locating the downhole tool with the apparatus for anchoring at a desired location in the casing. The method now includes the step of positioning the first cone closer to the second cone than the initial distance within the slip device so as to place the slip device in a set configuration with an extended diameter. In the set configuration, the first spiral inner slip surface is now in raised spiral threaded engagement with the first spiral outer cone surface, and the second spiral inner slip surface is in raised spiral threaded engagement with the second spiral outer cone surface. The outer slip surface is now spaced further from the first spiral outer cone surface and the second spiral outer cone surface in the raised spiral threaded engagement so that the outer slip surface can contact the wall of the casing for anchoring the downhole tool in the casing at the desired location.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a sectional view of a prior art anchoring apparatus for a downhole tool.

FIG. 2 is a perspective view of a downhole tool with prior art slips for anchoring.

FIG. 3 is a side elevation view of a prior art barrel slip anchoring apparatus.

FIG. 4 is a longitudinal sectional view of the prior art barrel slip anchoring apparatus of FIG. 3, showing the run-in configuration.

FIG. 5 is a longitudinal sectional view of the prior art barrel slip anchoring apparatus of FIG. 3, showing the expanded configuration.

FIG. 6 is a side elevation view of an embodiment of an anchoring apparatus, according to the present invention.

FIG. 7 is a longitudinal sectional view of the anchoring apparatus of FIG. 6, showing the run-in configuration.

FIG. 8 is a longitudinal sectional view of the anchoring apparatus of FIG. 6, showing the expanded configuration.

FIG. 9 is a partial sectional and partial elevation view of an embodiment of a slip device, according to the present invention.

FIG. 10 is a side elevation view of an embodiment of a first cone, according to the present invention.

FIG. 11 is a longitudinal sectional view of the embodiment of FIG. 6, showing assembly of the anchoring apparatus.

FIG. 12 is a side elevation view of an embodiment of an anchoring apparatus with a locking means, according to the present invention.

FIG. 13 is a longitudinal sectional view of the embodiment of an anchoring apparatus with a locking means, according to FIG. 12.

FIG. 14 is a side elevation view of an embodiment of an anchoring apparatus with a slip locking means, according to the present invention.

FIG. 15 is a side elevation view of an embodiment of an anchoring apparatus with rotation locking keys, according to the present invention.

FIG. 16 is a longitudinal sectional view of the embodiment of an anchoring apparatus with a rotation locking key, according to FIG. 15, in the run-in configuration.

FIG. 17 is a longitudinal sectional view of the embodiment of the anchoring apparatus with the rotation locking key, according to FIG. 15, in the set configuration.

FIG. 18 is an upper perspective view of an embodiment of a rotation locking key for an anchoring apparatus, according to the present invention.

FIG. 19 is a partial top plan view of the embodiment of the anchoring apparatus with the rotation locking key, according to FIG. 15.

FIG. 20 is a partial sectional view of the embodiment of the anchoring apparatus with the rotation locking key, according to FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION

The conventional barrel slip is a prior art anchoring component for a downhole tool, such as a plug or packer. The conventional barrel slip has ratchet engagement between the slip device and the cones, according to the straight threaded surfaces between the slip device and the cones. The consequences of this ratchet engagement by straight threaded surfaces include limitation on the load capacity of the prior art anchoring component and precarious tight tolerances between the straight threaded surfaces. Furthermore, the assembling and disassembling of the prior art anchoring component is only possible by a force-fit relationship between the conventional barrel slip and cones, which deforms the conventional barrel slip and risks damage. The conventional barrel slip and cones can be damaged before the anchoring component is even used, and the tight tolerances between the straight threaded surfaces are already susceptible to even the slightest damage. The present invention is an expandable spiral threaded apparatus 10 for anchoring to the casing with load capacity that is more evenly distributed and avoids the need for the tight tolerances between surfaces. Additionally, the expandable spiral threaded apparatus 10 can be assembled without deformation and with less risk of damage and with the possibility of disassembly without damage.

The present invention is an apparatus 10 for anchoring a downhole tool to a casing within a borehole, including a first cone 20, a second cone 30, and a slip device 40, as shown in FIGS. 6-17. The downhole tool can be a packer or plug or locking sleeve or other tool for attachment to a casing or tubing of a borehole. The downhole tool may incorporate a single apparatus 10 for anchoring or a plurality of apparatuses 10 for anchoring. Depending on the functionality of the downhole tool as a packer or plug, more than one apparatus 10 for anchoring may be needed. The apparatus 10 for anchoring is only a component of the downhole tool. There may be other components, such as sealing members, support rings, ball seats, and others, that determine the functionality of the particular type of downhole tool. The apparatus 10 for anchoring of the present invention can be incorporated into a variety of downhole tools. Any downhole tool that may require anchoring to the casing or tubing may be compatible with the present invention.

FIGS. 6-8 and 11-17 show embodiments of the first cone 20 having a first spiral threaded outer cone surface 22, being threaded in a first spiral direction 24. The first cone 20 is shown on the left side of the apparatus 10, but the first cone 20 could also be placed on the right side. The first cone 20 includes other features that are compatible with the downhole tool. FIGS. 6-8 and 11-17 show various portions within the inner bore of the first cone for attachment and cooperation with other downhole tool components.

FIGS. 6-8 and 10-17 show embodiments of the second cone 30 having a second spiral threaded outer cone surface 32, being threaded in a second spiral direction 34. FIG. 10 shows an elevation view of the second cone 30. Similar to the embodiments of the first cone 20, the second cone 30 is shown on the right side of the apparatus 10, but the second cone 30 could also be placed on the left side. The second cone 30 also includes other features that are compatible with the downhole tool. FIGS. 6-8 and 11-17 show various cam portions around the base of the second portion for attachment and cooperation with other downhole tool components.

The present invention does require the first cone 20 to be oriented towards the second cone 30. FIGS. 6-8 and 11-17 show the first cone 20 facing toward the second cone 30 within the slip device 40. The apparatus 10 for anchoring includes the first cone 20 being moveable towards the second cone 30 within the slip device 40. Furthermore, the first spiral direction 24 is opposite the second spiral direction 34. The rotation of the first cone 20 in the first spiral direction 24 can set the first cone 20 within the slip device 40 for the run-in configuration, while rotation of the second cone 30 in the second spiral direction 34 can set the second cone 30 within the slip device 40 for the run-in configuration. In this relationship, when the apparatus 10 for anchoring is assembled, the slip device 40 cannot rotate free from both the front cone 20 and the second cone 30. One rotation direction, such as the first spiral direction 24, will hold the first cone 20 on the slip device 40, while unscrewing the second cone 30. For the opposite rotation direction, such as the second spiral direction 34, the second cone 30 will be held on the slip device 40, while unscrewing the first cone 20.

Embodiments of the slip device 40 as a type of barrel slip are shown in FIGS. 6-9 and 11-17. In the isolated view of the slip device 40 in FIG. 9, the slip device 40 has an outer slip surface 42 and an inner slip surface 44. The outer slip surface 42 has as gripping means 46 for attachment to the casing or tubing or part of the borehole for anchoring. The gripping means 46 can be a toothed surface or textured surface. The gripping means 46 can also be any other known means for gripping, such as an adhesive or protrusions to engage the slip device 40 to the casing or tubing.

FIGS. 6-9 and 11-17 further show the inner slip surface 44 being comprised of a first spiral threaded inner slip surface 48 and a second spiral threaded inner slip surface 49.

FIGS. 6, 7, and 11-16 show the first spiral threaded inner slip surface 48 being in removable engagement with the first spiral threaded outer cone surface 22 of the first cone 20. The first spiral threaded inner slip surface 48 is in a spiral direction compatible with the first spiral direction 24 of the first spiral threaded outer cone surface 22. The first cone 20 can be rotated relative to the slip device 40 so that the first spiral threaded outer cone surface 22 engages the first spiral threaded inner slip surface 48. During assembly of the apparatus 10 for anchoring, the first cone 20 can move toward the center of the slip device 40 as the rotation causes lateral movement of the first cone 20 along the length of the slip device 40. FIG. 11 shows this process with the first cone 20 screwed into the slip device 40.

Similarly, the second spiral threaded inner slip surface 49 is in removable engagement with the second spiral threaded outer cone surface 32 of the second cone 30, as shown in FIGS. 6, 7, and 12-16. The second spiral threaded inner slip surface 49 is in a spiral direction compatible with the second spiral direction 34 of the second spiral threaded outer cone surface 32. The second cone 30 can be rotated relative to the slip device 40 so that the second spiral threaded outer cone surface 23 engages the second spiral threaded inner slip surface 49. During assembly of the apparatus 10 for anchoring, the second cone 30 can move toward the center of the slip device 40 as the rotation causes lateral movement of the second cone 30 along the length of the slip device 40. Because the first spiral direction 24 is opposite the second spiral direction 34 and because the second cone 30 is on the opposite end of the slip device 40, the second cone 30 moves in the opposite direction toward the center of the slip device 40.

The slip device 40 has a run-in configuration with an initial diameter, as shown in FIGS. 6, 7, 12, 13,15, and 16. The initial diameter is compatible with deploying the downhole tool through the casing or tubing to the downhole location. The initial diameter is the smallest diameter of the apparatus 10 for anchoring for the most clearance through the casing or tubing. In the run-in configuration, the first spiral threaded inner slip surface 48 is in spiral threaded engagement with the first spiral threaded outer cone surface 22, and the second spiral threaded inner slip surface 49 is in spiral threaded engagement with the second spiral threaded outer cone surface 32. The first cone 20 is positioned at an initial distance from the second cone 30 within the slip device 40 at the initial diameter.

The slip device 40 has a set configuration with an extended diameter, as shown in FIGS. 8 and 17. In the set configuration, the first cone 20 is positioned closer to the second cone 30 than the initial distance within the slip device 40. The movement of the first cone 20 and the second cone 30 toward each other is by lateral movement along the axis of the slip device 40. Pushing or pulling by a mandrel component or other mechanical actuation by another component of the downhole tool moves the first cone 20 and the second cone 30 toward each other without rotation relative to the slip device 40. The first spiral threaded inner slip surface 48 is in a raised spiral threaded engagement with the first spiral threaded outer cone surface 22, and the second spiral threaded inner slip surface 49 is in raised spiral threaded engagement with the second spiral threaded outer cone surface 32. The first cone 20 is positioned closer than the initial distance from the second cone 30 within the slip device 40 at the extended diameter.

In the set configuration, the extended diameter is greater than the initial diameter of the run-in configuration. The outer slip surface 42 is now extended to reach the casing or tubing. The gripping means 46 of the outer slip surface 42 can now anchor to the wall of the casing or tubing. The load capacity of the apparatus 10 for anchoring of the present invention is distributed along the length of the slip device 40. The load capacity to push the first cone 20 and second cone 30 against the straight threaded engagement is isolated at the concentric rings along the slip device 40, corresponding to the size of the straight threads. The load is focused on these concentric rings; thus, the concentric ring areas must maintain the tight tolerances at each straight thread in order to hold the set configuration in the prior art. Any slight damage to one straight thread weakens the prior art anchoring component. The load capacity is reduced by damage to one single straight thread. In the present invention, the load capacity to push the first cone 20 and the second cone 30 against the spiral threaded engagement is distributed all along the length of the slip device 40 because the spiral threads are all along the length of the slip device 40. The set configuration no longer hinges on one concentric ring of the slip device 40 to maintain the load. The apparatus 10 for anchoring of the present invention has more resilience with the greater distribution of load capacity. Furthermore, the criticality of each straight thread of the prior art is now moot with the continuous spiral thread along the length of the slip device 40.

FIGS. 8 and 17 show the first spiral threaded inner slip surface 48 being spaced further from the first spiral threaded outer cone surface 22 in the raised spiral threaded engagement than in the spiral threaded engagement of the run-in configuration. The second spiral threaded inner slip surface 49 is also spaced further from the second spiral threaded outer cone surface 32 in the raised spiral threaded engagement than in the spiral threaded engagement of the run-in configuration. The extended diameter of the slip device 40 in the set configuration corresponds the surfaces between the slip device 40 and the cones 20, 30 being pushed further apart as the first cone 20 and the second cone 30 move laterally toward each other within the slip device 40.

Other embodiments of the apparatus 10 for anchoring include a locking means 60 for the initial distance of the first cone 20 and the second cone 30 in the run-in configuration of the slip device 40. The locking means 60 maintains the initial distance between the first cone 20 and the second cone 30 in the run-in configuration. As the downhole tool is deployed through the casing or tubing, the locking means 60 prevents premature expansion of the initial diameter to the extended diameter of the slip device 40, until the downhole tool is at the desired location in the casing or tubing. FIGS. 12-13 show the embodiments of the apparatus 10 for anchoring with the locking means 60 being comprised of a plurality of shear screws 62. At least one first shear screw 64 of the plurality of shear screws is removably positioned on the first cone 20, and at least one second shear screw 66 of the plurality of shear screws being removably positioned on the second cone 30. When the downhole tool reaches the desired location in the casing or tubing, a threshold amount of load is applied to shear the shear screws 62 so that the first cone 20 and the second cone 30 are released to move from the initial distance closer to each other.

Embodiments of the slip device 40 include the slip device 40 being comprised of a barrel body 50 as shown in FIGS. 6-9 and 11-17. The barrel body 50 is comprised of a plurality of ribs 52. Each rib 52 of the plurality of ribs 52 is connected to an adjacent rib 52 of the plurality of ribs 52. The distance between each rib 52 of the slip device 40 expands from the run-in configuration to the set configuration. Spreading the ribs 52 corresponds to the extended diameter of the slip device 40.

Further embodiments of the slip device 40 being comprised of the barrel body 50 includes a slip locking means 54 to maintain the slip device 40 in the run-in configuration. Similar to the locking means 60 for the first cone 20 and the second cone 30, the slip locking means 54 holds the slip device 40 in the run-in configuration at the initial diameter. When the downhole tool reaches the desired location in the casing or tubing, a threshold amount of load is applied to release the slip locking means 54 to allow the slip device 40 to expand from the initial diameter to the extended diameter of the set configuration. FIG. 14 shows the embodiment of the slip locking means 54 being comprised of a plurality of tabs 56 for the barrel body 50 as the slip device 40. Each rib 52 of the plurality of ribs 52 and an adjacent rib 52 are held in position around the first cone 20 and the second 30 cone at the initial diameter by a corresponding tab 56. The plurality of tabs 56 removably connect each rib 52 of the plurality of ribs 52 in the run-in configuration. The tabs 56 are fractured or split by the threshold amount of load applied to release the slip lock means 54 so that the ribs 52 are no longer held at the initial diameter by the tabs 56.

FIGS. 15-20 show a further embodiment of the present invention including a first rotation locking key 70 being mounted on the first cone 20 and a second rotation locking key 80 being mounted on the second cone 30. The spiral threaded engagement of the run-in configuration and the raised spiral threaded engagement of the set configuration, the apparatus 10 for anchoring must prevent rotation of the slip device 40 relative to the first cone 20 and the second cone 30. Although the screwing action is advantageous for assembling the apparatus 10 to the run-in configuration, there is a need to prevent a reverse screwing action or un-screwing. The load to push the surfaces along the spiral threaded engagement must not be re-directed to rotation for unscrewing the cones 20, 30 from the slip device 40. The present invention modifies the first cone 20 and the second cone 30 to incorporate the first rotation locking key 70 and the second rotation locking key 80, respectively to prevent this re-direction of the load on the slip device 40.

For the embodiment of the slip device 40 as a barrel body 50 being comprised of a plurality of ribs 52, as in FIGS. 15-17, the first rotation locking key 70 is positioned between a first rib 52 and a corresponding first adjacent rib 52 so as to prevent rotation of the first spiral threaded inner slip surface 48 relative to the first spiral threaded outer cone surface 22 with the slip device 40 in the set configuration. Similarly, the second rotation locking key 80 is positioned between a second rib 52 and a corresponding second adjacent rib 52 so as to prevent rotation of the second spiral threaded inner slip surface 49 relative to the second spiral threaded outer cone surface 32 with the slip device in the set configuration. In the raised spiral threaded engagement of the set configuration, the load on the slip device 40 to expand the slip device 40 cannot be re-directed to unscrew either the first cone 20 or the second cone 30.

FIGS. 18-20 show embodiments of the first rotation locking key 70 and the second rotation locking key 80. The first rotation locking key 70 can be comprised of a first anchor end 72 and a first flange body 74 extending radial to the first anchor end 72. The first anchor end 72 is attached to the first cone 20 by any known means, such as a threaded screw, adhesive, or bolt. The first flange body 74 extends between the first rib 52 and the corresponding first adjacent rib 52 for preventing rotation of the ribs 52 around the first cone 20. The first cone 20 cannot be unscrewed from the slip device 40 as a barrel body 50 in both the run-in configuration and the set configuration. Similarly, the second rotation locking key 80 can be comprised of a second anchor end 82 and a second flange body 84 extending radial to the second anchor end 82. The second anchor end 82 is attached to the second cone 30 by any known means, such as a threaded screw, adhesive, or bolt. The second flange body 84 extends between the second rib 52 and the corresponding second adjacent rib for preventing rotation of the ribs 52 around the second cone 30. The second cone 30 cannot be unscrewed from the slip device 40 as a barrel body 50 in both the run-in configuration and the set configuration.

The present invention further includes a method for assembling the apparatus 10 for anchoring the downhole tool. The apparatus 10 for anchoring includes the first cone 20 having a first spiral threaded outer cone surface 22, the second cone 30 having a second spiral threaded outer cone surface 32, and the slip device 40 having an outer slip surface 42 and an inner slip surface 44. The first spiral threaded outer cone surface 22 is threaded in a first spiral direction 24, and the second spiral threaded outer cone surface 32 is threaded in a second spiral direction 34 opposite to the first spiral direction 24. These separate components are shown in FIGS. 6-17. FIG. 9 shows the slip device 40. FIG. 10 shows the second cone 30.

The method includes the step of inserting the first cone 20 into the slip device 40, the first spiral threaded outer cone surface 22 being threaded in a first spiral direction 24, and the step of inserting a second cone 30 into the slip device 40 opposite the first cone 20. The second cone 30 has a second spiral threaded outer cone surface 32 being threaded in a second spiral direction 34. Inserting the first cone 20 and the second cone 30 set the slip device 40 in a run-in configuration with an initial diameter.

The first spiral threaded outer cone surface 22 is in spiral threaded engagement with the first spiral threaded inner slip surface 48, and the second spiral threaded outer cone surface 32 is in spiral threaded engagement with the second spiral threaded inner slip surface 49. FIG. 11 shows the step of inserting the second cone 30, after the step of inserting the first cone 20. It is acknowledged that the sequence can be reversed. The second cone 30 can be inserted first with the first cone inserted second. The sequence is determined by other components of the downhole tool. Some other components attached to either the first cone 20 or the second cone 30 may require inserting before the other cone.

Embodiments of the method for assembling include the step of inserting the first cone 20 being comprised of rotating the first spiral threaded outer cone surface 32 into a spiral threaded engagement with the first spiral threaded inner slip surface 48. The step of inserting the second cone 30 is also comprised of rotating the second spiral threaded outer cone surface 32 into a spiral threaded engagement with the second spiral threaded inner slip surface 49. The first cone 20 faces toward the second cone 30 within the slip device 40. The first cone 20 is positioned at an initial distance from the second cone 30 within the slip device 40. The method assembles the apparatus 10 for anchoring into the run-in configuration with the initial diameter of the slip device 40 and the first cone 20 at an initial distance from the second cone 30.

Embodiments of the method include the outer slip surface 42 having a gripping means 46 for the casing or tubing. The slip device 40 of the method may also be comprised of a barrel body 50 having a plurality of ribs 52. Each rib 52 can be connected to an adjacent rib 52. Each rib 52 remains threaded to form the inner slip surface 44. Further embodiments include the slip device 40 having a slip locking means 54, as shown in FIG. 14. The slip locking means 54 as a plurality of tabs 56 allows the barrel body 50 to be held in position around the first cone 20 and the second cone 30.

FIGS. 12-13 show a further embodiment of the method for assembling, including the step of installing a locking means 60 to maintain the initial distance between the first cone 20 and the second cone 30. FIGS. 12-13 shows the locking means 60 being comprised of a plurality of shear screws 62. The step of installing the locking means 60 comprises the steps of removably positioning at least one first shear screw 62 of the plurality of shear screws on the first cone 20 and removably positioning at least one second shear screw 62 of the plurality of shear screws on the second cone 30.

FIGS. 15-20 show another embodiment of the method for assembling, including the step of mounting a first rotation locking key 70 on the first cone 20 so as to prevent rotation of the first spiral threaded inner slip surface 48 relative to the first spiral threaded outer cone surface 22. The first rotation locking key 70 prevents rotation when the slip device 40 is in both the run-in configuration and the set configuration. The method for assembling further includes mounting a second rotation locking key 80 on the second cone 30 so as to prevent rotation of the second spiral inner slip surface 49 relative to the second spiral outer cone surface 32. The second rotation locking key 80 also prevents rotation when the slip device 40 is in both the run-in configuration and the set configuration. FIGS. 15-17 show the slip device 40 being comprised of a barrel body 50 having a plurality of ribs 52. In these embodiments, the first rotation locking key 70 is positioned between a first rib 52 and a corresponding first adjacent rib 52, and the second rotation locking key 80 is positioned between a second rib 52 and a corresponding second adjacent rib 52. The first rotation locking key 70 and the second rotation locking key 80 are offset and never fit between the same rib and adjacent rib.

The present invention may further include reversing the steps of assembling for a method of disassembling. Rotating the first cone 20 in the opposite direction will separate the first cone 20 from the slip device 40. If the first cone 20 was not set properly, then the first cone 20 can be unscrewed from the slip device 40, even if the second cone 30 has already been inserted into the slip device 40. Unlike the prior art, the slip device is not deformed by expansion in order to fit over the straight threads. The slip device does not need to be re-expanded and further damaged in order to replace a cone. The present invention has reduced the risk of damage during assembly, such that disassembly is possible and may result in reuse of the slip device with a different set of cones.

The present invention further includes the method of anchoring a downhole tool to a casing within a borehole. With the apparatus 10 for anchoring assembled, according to the method for assembly, the slip device 40 is in the run-in configuration. The method for anchoring the downhole tool includes deploying the downhole tool with the slip device in the run-in configuration into the casing. The first spiral inner slip surface 48 is in spiral threaded engagement with the first spiral outer cone surface 22. The second spiral inner slip surface 49 is in spiral threaded engagement with the second spiral outer cone surface 32. The downhole tool, with the apparatus 10 for anchoring, is located at a desired location in the casing. The method now includes the step of positioning the first cone 20 closer to the second cone 30 than the initial distance within the slip device 40 so as to place the slip device 40 in a set configuration with an extended diameter. The step of positioning can be performed by any known process, such as a hydraulic pressure component or sliding of a cam component on a mandrel. The extended diameter is greater than the initial diameter, such that the slip device 40 holds the downhole tool at the desired location.

In the set configuration, the first spiral inner slip surface 48 is now in raised spiral threaded engagement with the first spiral outer cone surface 22, and the second spiral inner slip surface 49 is in raised spiral threaded engagement with the second spiral outer cone surface 32. The outer slip surface 44 is now spaced further from the first spiral outer cone surface 22 and the second spiral outer cone surface 32 in the raised spiral threaded engagement so that the outer slip surface 44 can contact the wall of the casing.

The present invention provides an apparatus for anchoring a downhole tool to a casing or tubing within a borehole, according a spiral threaded engagement and a raised spiral threaded engagement between a slip device and first and second cones. The first cone is moved closer to the second cone within the slip device to expand the slip device from an initial diameter in the run-in configuration to an extended diameter in the set configuration. The initial diameter corresponds to the spiral threaded engagement, and the extended diameter corresponds to the raised spiral threaded engagement.

The spiral threaded engagement can be between a barrel slip with a spiral threaded inner slip surface and cones with spiral threaded outer cone surfaces. The spiral threaded inner slip surface is divided into a first spiral threaded inner slip surface and a second spiral threaded inner slip surface. The spiral direction of the first spiral threaded inner slip surface and the second spiral threaded inner slip surface oppose each other and correspond to the spiral threaded outer cone surfaces of the respective cones. The cones are also facing each other and have a spiral direction opposite to each other.

Further modifications are required beyond the conversion of straight threads to spiral threads, and particularly, the opposing spiral threads. The present invention includes multiple locking systems to prevent premature expansion and unscrewing or reverse rotating the cones from the slip device. The load exerted against the slip device cannot be re-directed to rotate the cones in the opposite directions to release the cones from the slip device. The present invention includes locks for the initial distance between the first cone and the second cone. The present invention includes locks for the ribs of a barrel slip as the slip device. The present invention further includes a rotation locking key to fit between ribs of the barrel slip as the slip device. The rotation locking key prevents rotation in both the run-in configuration and the set configuration. The rotation locking key must be installed after the slip device has been set in the run-in configuration.

The present invention provides a method of assembling a spiral threaded apparatus for anchoring a downhole tool to a casing or tubing with reduced risk of deformation and damaging the slip device as a barrel slip. Instead of deforming the components to snap-fit over straight threads, the cones of the present invention are inserted by rotating along the spiral threads. The assembly by screwing further results in possible disassembly by unscrewing. The reverse rotation will remove the cones from the slip device. If the first cone is not set properly, the first cone can be unscrewed from the slip device, even after the second cone has been inserted. In the prior art, the barrel slip is expanded to fit over the cones, and there is no way to remove either cone without damage to the barrel slip, if the cones need to be re-set. There is less risk of damage during disassembly, so some components of the present invention may be reuseable. The barrel slip has not been expanded to snap fit over the cones, and the barrel slip does not have to be damaged to remove one of the cones. The prior art snap-fit engagement of straight threads generally damages components during removal or any disassembly and prevents reuse. Additionally, the spiral threaded engagement and raised spiral threaded engagement distributes load capacity along the slip device, instead of isolating load capacity at the edges of straight threads. With such dependence on these edges of the straight threads, the spiral threads of the present invention are more robust and relax the tight tolerances of the prior art threaded surfaces.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated structures, construction and method can be made without departing from the true spirit of the invention.

EXPANDABLE SPIRAL THREADED APPARATUS AND METHOD FOR ANCHORING A DOWNHOLE TOOL TO A CASING, AND METHOD FOR ASSEMBLING THE APPARATUS

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