Patent Application
20240287867
See Application Data Sheet.
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The present invention relates to isolating zones in a wellbore. More particularly, the present invention relates a frac plug system that has a run-in configuration to be deployed into a wellbore and a set configuration at a desired location in the wellbore. The frac plug sets a seal for isolating zones in a wellbore. Even more particularly, the present invention relates to a frac plug with a locked set configuration by the cone and anchor mandrel in ratchet locked engagement.
Within a wellbore, the hydrocarbons are located at particular depths within a rock formation. These depths can be organized into production zones so that the delivery of production fluids can be targeted to the location of the hydrocarbons. The production fluids facilitate the recovery of the hydrocarbons from the wellbore. Other depth levels do not contain hydrocarbons, which can be called “non-productive zones”. There is no need to waste production fluids on non-productive zones without hydrocarbons. Thus, the productive zones are isolated from the non-productive zones for the recovery of hydrocarbons from the wellbore.
There are known downhole tools to separate a production zone from a non-productive zone so that the production fluids can be delivered to the production zone and not the non-productive zone. Examples of downhole tools to isolate zones include a plug, a packer or other tool with an isolation valve.
In the conventional process, the frac plug or frac plug device is run-in to a downhole location. When located in the correct place, the setting tool that traveled with the frac plug device will set the packer, i.e. expand the frac plug against the walls of the borehole. Then, the settling tool is removed. The frac plug still must be activated in order seal the zone. The frac plug is sealed to the borehole, but fluid still flows through the packer. Conventionally, a frac ball is dropped into the borehole. The frac ball travels to the downhole location to sit on a ball seat, which triggers expansion of the frac plug to the borehole walls and can even be incorporated as part of the seal across the frac plug. Fracking can commence with the seal across the packer. The frac fluids are only delivered to the isolated zone, and production fluids are only harvested from the isolated zone.
There are both well known frac plug devices that can be actuated by a frac ball and others that can be actuated by other setting components. U.S. Pat. No. 2,627,317, issued on Feb. 2, 1953 to Baker, discloses a well tester with pre-set frac ball. The frac balls expands the frac plug and forms the seal across the frac plug. U.S. Pat. No. 3,298,437, issued on Jan. 17, 1967 to Conrad, discloses a mandrel assembly as the setting component to expand plug components to the borehole walls by compression and a solid tubular member for the seal across the frac plug.
There are also simplified, compact, and condensed frac plug systems comprised of different material compositions. Fewer components and selection of material composition allow for frac plugs to the removed more easily after use. As the material selection of components is controlled, the use of drilling out removal or the use of dissolving metallic or non-metallic compositions can be selected. As the number of components is reduced, the amount of milling out or the amount of dissolving chemicals can be reduced. Some of these simplified and condensed frac plug systems are wedge type or ramp type frac plug systems comprised of a wedge or ramp, a sealing ring, and a slip device.
Various patents and publications have been granted for wedge type or ramp type frac plug systems. US Patent Publication No. 20130299192, published on Nov. 14, 2013 for Xu et al and granted as U.S. Pat. No. 8,950,504, discloses a plug comprised of a frustoconical member, a slip or sleeve that expands to the borehole wall, and a seal at the tip of the slip. The selected material composition is metal composite. US Patent Publication No. 20130186649, published on Jul. 25, 2013 for Xu et al and granted as U.S. Pat. No. 9,309,733, discloses a plug comprised of a cone removably attached to a mandrel, a slip or sleeve that expands to the borehole wall, and a seal at the tip of the slip. The selected material composition is metal composite. The mandrel pushes the cone to expand the slip and releases from the cone, when the plug is set. U.S. Pat. No. 10,000,991, issued on Jun. 19, 2018 to Harris et al, discloses a plug comprised of an annular wedge with collet fingers, an annular slip, and a sealing ring. U.S. Pat. No. 10,000,991, issued on Jun. 19, 2018 to Harris et al, discloses a plug comprised of an annular wedge with collet fingers, an annular slip, and a sealing ring. U.S. Pat. No. 9,835,003, issued on Dec. 5, 2017 to Harris et al, discloses a non-metallic composite annular wedge, annular slip, and a sealing ring.
There is a need for increased reliability of these known simplified wedge type or ramp type frac plugs. The friction fit setting of the single set of wedge and slip engagement is directional. Without a second set of wedge and slip engagement to the borehole wall in the opposite direction, the simplified wedge type or ramp type frac plugs rely on frictional engagement between the one wedge or cone and the one slip device. Forces in the opposite direction may dislodge and release the frac plug. Any pressure pulse or waiver in directional pressure may loosen and affect the integrity of the seal of these simplified wedge type or ramp type frac plugs.
It is an object of the present invention to provide a frac plug device to isolate zones in a wellbore.
It is an object of the present invention to provide a simplified short frac plug device to maintain seal to the borehole wall and to prevent premature release from the borehole.
It is an object of the present invention to provide a frac plug device having a cone with a threaded cone portion and an anchor mandrel with an exterior threaded mandrel portion cooperative with the threaded cone portion.
It is another object of the present invention to provide a frac plug device having a dissolvable metal cone with a threaded cone portion and a dissolvable metal anchor mandrel with an exterior threaded mandrel portion.
It is an object of the present invention to provide a simplified short frac plug device set by friction between the cone and the slip device and single direction ratchet locking threaded engagement between the cone and the anchor mandrel.
It is another object of the present invention to provide a simplified short frac plug device to prevent premature release of cone from the slip.
It is another object of the present invention to provide a simplified short frac plug device to maintain the seal to the borehole by friction between the cone and the slip device and ratchet locking threaded engagement between the cone and the anchor mandrel.
These and other objectives and advantages of the present invention will become apparent from a reading of the attached specification, drawings and claims.
Embodiments of the present invention include a simplified, short, and compact wedge type or ramp type frac plug device that locks the set configuration to maintain the seal in the wellbore and prevent premature release of the cone from the slip device. The frac plug device includes a cone, an anchor mandrel, a cap member, a slip device, and a sealing member. The frac plug device has a run-in configuration for the deployment into the wellbore and a set configuration at the desired location so that the wellbore is sealed at the desired location. In the set configuration, the frac plug device has both the friction fit engagement of the cone and the slip device and a single direction rachet locked engagement of the cone and an anchor mandrel.
The cone of the frac plug device of the present invention includes an inner core with a threaded cone portion at a second cone end and a tapered outer surface decreasing in outer cone diameter toward the second cone end. The tapered outer surface is compatible with the slip device and the sealing member. The threaded cone portion is dimensioned to hold the anchor mandrel in the ratchet locked engagement in both the run-in and the set configurations of the frac plug device.
Embodiments of the anchor mandrel include an exterior threaded mandrel portion at a first anchor mandrel end. In a particular embodiment, the anchor mandrel is comprised of a plurality of collet fingers and a collet base. The collet fingers extend from the collet base toward the cone. The exterior threaded mandrel portion can be comprised of each exterior collet finger surface of the plurality of collet fingers. The ratchet locked engagement restricts movement of the anchor mandrel toward the cone. The components with threads are comprised of a metal material and may be dissolvable or non-dissolvable metal.
A tapered inner surface of the slip device is in sliding engagement with the tapered outer surface of the cone according to the threaded cone portion of the cone in ratchet locked engagement with the exterior threaded mandrel portion of the anchor mandrel. The present invention has a locked set configuration to prevent the release of the seal of the frac plug device at the desired location in the wellbore. The locking of the set configuration is achieved in the same setting action in the same direction as transitioning from the run-in configuration to the set configuration.
The anchor mandrel is removably engaged to the cap member. The cap member is engaged with the anchor mandrel, while a first cap end faces the slip device. In the locked set configuration, the cone and the anchor mandrel are in a ratchet locked position with the cap member holding the slip device in the extended position. The slip device is prevented from retracting back to the initial position. The cap member exerts pressure against the slip device so as to prevent release of the slip device from the cone.
The frac plug device can also comprise a seal support ring between the sealing member and the slip device to strengthen the seal of the frac plug device in the locked set configuration and prevent extrusion of the sealing member. The seal support ring is similarly expandable in diameter in the transition from the run-in configuration to the locked set configuration of the present invention. Other embodiments include the tapered outer surface being comprised of a notch so as to engage the sealing member for support and stabilization of the seal of the frac plug device in the locked set configuration.
Embodiments of the present invention further include a method of isolating a zone in a wellbore with the frac plug device. The method comprises the steps of deploying the frac plug device in the run-in configuration with the cone and the anchor mandrel at a first ratchet locked position; moving the threaded cone portion along the exterior threaded mandrel portion from the first ratchet locked position toward a second ratchet locked position closer to the first cone end; and pushing the tapered inner surface along the tapered outer surface with the cap member against the second slip end. The method further includes placing the frac plug device in the set configuration with the cone and the anchor mandrel at the second ratchet locked position. The set configuration is a locked set configuration with the ratchet lock engagement of the cone and the anchor mandrel holding the cap member against the slip device to prevent retraction of the slip device. In the set configuration, the method further includes setting the slip device in a borehole wall with the outer engagement surface in the extended position and sealing the sealing member in the expanded position against the borehole wall.
Wedge type or ramp type frac plugs are simplified, short and compact. These qualities make ramp type frac plugs popular for being easy to use and quick to set. There is a single direction setting that relies on simple friction between the tapered outer surface of a wedge or cone and the complementary tapered inner surface of a slip device. A serious consequence of this simple single direction setting is a similarly simple single direction unsetting. Just as easily and quickly the ramp type frac plug can be set, the ramp type frac plug can be unset with the loss of friction fit engagement of the tapered inner surface of the slip device against the tapered outer surface of the cone. Forces in the opposite direction of the single direction for setting, even jostling vibration, may release the cone from the slip device or degrade the friction fit engagement, which releases or at least reduces the integrity of the seal against the borehole by the frac plug. The present invention is a ramp type frac plug device 10 that locks the cone and the slip device in the set configuration in addition to the friction fit engagement of the cone and the slip device.
The frac plug device 10 of the present invention include a cone 20, an anchor mandrel 32, a cap member 60, a slip device 70, and a sealing member 90, as shown in
In the present invention, the cone 20 and the anchor mandrel 32 can be fabricated of a metal material. A metallic composition of the components with threads (the threaded cone portion 30 and the exterior threaded mandrel portion 38) is important for proper manufacture. Threads with the required sharp edges and resistance to deformation for the single direction ratchet locked engagement of the present invention are preferably comprised of metal compositions, dissolvable or non-dissolvable. With dissolvable metal material, the frac plug device 10 can be removed with chemical compositions injected into the wellbore. With non-dissolvable metal materials, the frac plug device 10 may require conventional milling or drilling out for removal.
In the present invention, the tapered inner surface 78 of the slip device 70 is in sliding engagement with the tapered outer surface 28 of the cone 20 according to the threaded cone portion 30 of the cone 20 in ratchet locked engagement with the exterior threaded mandrel portion 38 of the anchor mandrel 32. The present invention has a locked set configuration to prevent the release of the seal of the frac plug device 10 at the desired location in the wellbore. The set configuration of the prior art ramp type frac plugs lack the additional support and redundancy to maintain the set configuration. There is more than friction to prevent the slip device from releasing the cone. The frac plug device 10 remains a ramp type frac plug that is still simple and compact. The locking of the set configuration is achieved in the same setting action as transitioning from the run-in configuration to the set configuration. The locking is achieved with the same direction of movement of the cone 20 toward the slip device 70 as transitioning from the run-in configuration to the set configuration.
The first anchor mandrel end 34 is closer to the first cone end 22 in the second ratchet locked position than in the first ratchet locked position. The second ratchet locked position must be sufficient for the threaded cone portion 30 to anchor the anchor mandrel 32 so that the anchor mandrel 32 cannot shift or wiggle in the set configuration of the frac plug device 10. Thus, the set configuration of the frac plug device is a locked set configuration. Consistent with transition from the run-in configuration to the set configuration, the outer engagement surface 76 of the slip device 70 is moved to the extended position so as to hold the slip device 70 in the borehole wall, and the sealing member 90 is in the expanded position so as to seal against the borehole wall. The slip device 70 and the sealing member 90 are at their largest diameters in the set configuration, which is a locked set configuration for the frac plug device 10 of the present invention.
The embodiment of
An embodiment of the cap member 60 in
The frac plug device 10 can also comprise a seal support ring 48 between the sealing member 90 and the slip device 70. The seal support ring 48 is an additional component to strengthen the seal of the frac plug device 10 in the locked set configuration of the present invention. The seal support ring 48 can additionally prevent extrusion of the sealing member 90, depending on the material composition of the sealing member 90.
Embodiments of the present invention further include a method of isolating a zone in a wellbore with the frac plug device 10. The method comprises the step of deploying the frac plug device 10 in the run-in configuration with the cone 20 and the anchor mandrel 32 at a first ratchet locked position, the slip device 70 in the initial position, and the sealing member 90 in the original position. Next, the method includes moving the threaded cone portion 30 along the exterior threaded mandrel portion 38 from the first ratchet locked position toward a second ratchet locked position closer to the first cone end 22 and pushing the tapered inner surface 78 along the tapered outer surface 28 with the cap member 60 against the second slip end 74. The method further includes placing the frac plug device 10 in the set configuration with the cone 20 and the anchor mandrel 32 at the second ratchet locked position, the slip device 70 in the extended position, and the sealing member 90 in the expanded position. The set configuration is a locked set configuration with the ratchet lock engagement of the cone 20 and the anchor mandrel 32 holding the cap member 60 against the slip device 70 to prevent retraction of the slip device 70.
In the set configuration, the method further includes setting the slip device 70 in a borehole wall with the outer engagement surface 76 in the extended position and sealing the sealing member 90 in the expanded position against the borehole wall. The slip device 70 and the sealing member 90 are at larger diameters than in the run-in configuration.
Embodiments of the method of the present invention also include the anchor mandrel 32 being comprised of a plurality of collet fingers 40 and a collet base 42. The collet base 42 is on the second anchor mandrel end 36, and the collet fingers 40 extend from the collet base 42 toward the first anchor mandrel end 34 and toward the cone 20. The step of moving the threaded cone portion 30 at the first ratchet locked position toward the second ratchet locked position is further comprised of bending each collet finger 40 and restoring each collet finger 40. There is a snap fit action for the ratchet lock engagement between the threaded cone portion 30 and the exterior threaded mandrel portion 38. The individual threaded are oriented in one direction so that the threaded cone portion 30 cannot move backwards against the exterior threaded mandrel portion 38 toward the first ratchet locked position.
An alternate embodiment of the present invention includes the frac plug device 10 comprising a seal support ring 48 between the sealing member 90 and the slip device 70. In this embodiment of
In the embodiments of the tapered outer surface 28 being comprised of a notch 58 between the first cone end 22 and the second cone end 24, the step of placing the cone in the set configuration, the slip device in the extended position, and the sealing member in the expanded position further comprises the step of engaging the sealing member 90 in the expanded position to the notch 58. The notch 58 and the cap member 70 further lock the sealing member 90 in the expanded position and the slip device 70 in the extended position. The cone 20 and slip device 70 are anchored by more than friction fit engagement between tapered surfaces and resist release of the cone 20 from the slip device 70.
The frac plug device of the present invention isolates zones in a wellbore. The present invention is a ramp type frac plug that is still a simplified short and compact frac plug device to both maintain seal to the borehole wall and prevent premature release from the borehole. The frac plug device has a cone with an internal ratchet locking threaded portion and an anchor mandrel with an outer ratchet locking threaded portion cooperative with the internal ratchet locking threaded portion. The ratchet lock engagement between the cone and the anchor mandrel prevents backward movement of the cone away from the anchor mandrel so that the cap member engaged with the anchor mandrel locks the slip device in position on the cone. The frag plug device of the present invention has a set configuration that is a locked set configuration with more resilience and reliability.
The frac plug device of the present invention includes a dissolvable metal cone with a threaded cone portion and a dissolvable metal anchor mandrel with an exterior threaded mandrel portion. The single direction ratchet locked engagement between the cone and the anchor mandrel is reliable and able to be manufactured concurrent with other simplified and compact components for a ramp type frac plug device. The set configuration of the frac plug device is no longer determined by a friction fit engagement between tapered surfaces of the cone and the slip device. The set configuration of the present invention is a locked set configuration by both the friction fit engagement between the cone and the slip device and the single direction ratchet locking threaded engagement between the cone and the anchor mandrel. The simplified short frac plug device of the present invention has the locked set configuration to prevent premature release of cone from the slip and to maintain the seal to the borehole by friction between the cone and the slip device and ratchet locking threaded engagement between the cone and the anchor mandrel.
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.
