LINER HANGER

A liner hanger includes an outer tube assembly, an inner tube and a torque transmitting assembly. The torque transmitting assembly has a torque strip fixedly arranged on the outer wall of the inner tube, a torque block fixedly arranged on the inner wall of the first outer tube, a transmission nut and a reverse-thread nut which are in axial sliding fit with the torque strip, and the outer peripheries of the transmission nut and the reverse-thread nut are threadedly connected with the first outer tube and the second outer tube respectively. The thread-rotating direction between the reverse-thread nut and the second outer tube is opposite to the thread-rotating direction between the transmission nut and the first outer tube, and the inner tube is configured to be capable of rotating forward, thereby moving the reverse-thread nut upward to disengage from the second outer tube.

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Description
FIELD OF THE INVENTION

The invention belongs to the technical field of drilling engineering, and particularly relates to a liner hanger.

BACKGROUND

In oil and gas well cementing operation in petroleum engineering industry, a liner hanger is mostly adopted to be engaged with the well cementing devices, and a liner is conveyed to a designed position in a liner hanging manner to perform hanging cementing operation. However, as the number of deep wells, ultra-deep wells, highly deviated wells and horizontal wells increases, there are difficulties in achieving safe and effective liner running. Meanwhile, during well cementing construction, the friction of the tube on fluid is large, and the tube may be in contact with the well, and the displacement efficiency is low, and the well cementing quality is poor. When circulation de-jamming is adopted, the leakage phenomenon is easily caused by circulation pressure at certain low-pressure lost circulation zone. Because well conditions are more and more complex, the liner cementing construction operation is more and more difficult, and more severe requirements are needed on the function and performance of a liner hanger.

Conventional liner hangers have been increasingly unable to meet the ever-increasing demands of oil and gas well exploration and development. On one hand, although the conventional liner hanger has high temperature and high pressure resistance and good hanging reliability, the liner hanger is likely to be hung prematurely in the rapid liner running and mid-way high flow rate circulation process of the liner, causing failure to run the liner/tubular string into the designated well depth, and finally, all the string of tubes must only be pulled out. On the other hand, the string of tubes may cause that the liner hanger fails to set during running or circulation if the pressure transfer holes of the liner hanger are blocked by iron ore powder or barite particles in the drilling fluid.

In order to solve the problems, recently a hydraulic liner hanger is commonly used, and jamming is released by rotation in the operation of liner running, and meanwhile, the well cementing quality is improved by rotating operation during well cementing operation. Chinese patent document CN201024940Y discloses a built-in rotary liner hanger which can rotate a liner only when a tube runs in, but a rotating operation for cementing work cannot be performed after the hanger is released, and thus the cementing quality cannot be improved by the rotating operation during cementing operation. The Chinese patent document CN201410253648.X can realize liner rotating operation during liner running and cementing operation, but the structure has the risk of releasing prematurely when being lifted and lowered due to jamming in the running operation. Chinese patent document CN200710178298.5 discloses an expandable type rotary liner hanger which can realize rotary running and rotary cementing operations, but the releasing operation is realized after the cementing operation, the operation is at large risk, and there is a risk that the hanger cannot be taken out after releasing operation.

There remains a need in cementing field for an improved liner hanger that not only facilitates efficient and rapid running of the liner, but also enables high flow rate circulation mid-way during the running of the liner, and effectively achieves de-jamming by rotating the liner hanger, and prevents premature setting of the liner hanger.

SUMMARY

In view of the above-mentioned technical problems, the present invention aims to provide a liner hanger which not only facilitates efficient and rapid running of a liner, but also enables high flow rate circulation mid-way during the running of the liner, and effectively achieves de-jamming by rotating the liner hanger, and prevents premature setting of the liner hanger. The liner hanger can also complete releasing before well cementing, and can improve the quality of well cementing by rotating operation after releasing.

According to the present invention, there is provided a liner hanger comprising a hanger body, wherein the liner hanger further comprises:

    • an outer tube assembly which includes a first outer tube and a second outer tube axially inserted with each other, and the second outer tube is connected with hanger body;
    • an inner tube which is sleeved inside the outer tube assembly; and
    • a torque transfer assembly which is disposed between the outer tube assembly and the inner tube, the torque transfer assembly comprising:
      • a first torque transmitting mechanism which is fixedly arranged on an outer wall of the inner tube;
      • a second torque transmitting mechanism which is fixedly disposed on an inner wall of the first outer tube, and the second torque transmitting mechanism is axially slidably engaged with the first torque transmitting mechanism;
      • a transmission nut and a reverse-thread nut which are axially slidably engaged with the first torque transfer mechanism, and the outer peripheries of the transmission nut and the reverse-thread nut are threadedly connected to the first outer tube and the second outer tube respectively, wherein the thread-rotating direction between the reverse-thread nut and the second outer tube is opposite to the thread-rotating direction between the transmission nut and the first outer tube, and the inner tube is configured to be capable of rotating forward, thereby moving the reverse-thread nut upward to disengage from the second outer tube.

In a particular embodiment, the first torque transmitting mechanism is a torque strip, and the torque strip is preferably disposed in a groove on the outer wall of the inner tube, and the second torque transmitting mechanism is a torque block, and the torque block is preferably disposed within a groove on an inner wall of the first outer tube.

In a particular embodiment, a stopping portion is provided inside the first outer tube, and in the releasing operation, the inner tube is rotated relative to the outer tube assembly to disengage the reverse-thread nut from the threads of the second outer tube, thereby allowing the inner tube to move up relative to the second outer tube to complete the releasing operation; at the same time, the transmission nut moves to abut against the stopping portion, so that torque is continuously transmitted between the first outer tube and the inner tube.

In a particular embodiment, in an initial state, a lower end of the reverse-thread nut axially abuts the inner tube, and an upper portion of an inner wall of the second outer tube is a smooth wall surface for providing a moving space for the reverse-thread nut to be disengaged from the threads on the inner wall of the second outer tube.

In a particular embodiment, a lower joint is provided at a lower end of the inner tube, and an outer diameter of the lower joint is larger than an outer diameter of the inner tube, and a lower end of the reverse-thread nut axially abuts an upper end face of the lower joint in an initial state.

In a particular embodiment, the liner hanger further comprises a locking assembly for preventing downward movement of the inner tube relative to the outer tube assembly in an initial state, the locking assembly comprising:

    • a first hydraulic cylinder which is arranged on the outer wall of the inner tube by means of a shearing pin, and the top of the first outer tube is sleeved between the first hydraulic cylinder and the inner tube; and
    • a stopping block which is radially slidably arranged on the tube wall of the top of the first outer tube for passing therethrough, and one end of the stopping block is inserted into the outer wall of the inner tube in an initial state, and the other end of the stopping block is abutted against the first hydraulic cylinder.

In a particular embodiment, a ramp is provided at the junction of the inner tube and the stopping block which is able to push the stopping block radially outwards from inside of the inner tube when the inner tube moves downwards relative to the first outer tube in case that the first hydraulic cylinder no longer abuts the stopping block.

In a particular embodiment, the locking assembly further comprises an elastic pressure-bearing block disposed inside the inner tube by means of a shearing pin, and a channel communicating the first hydraulic cylinder with the inner cavity of the inner tube is provided in the tube wall of the inner tube, and the elastic pressure-bearing block seals the channel in an initial state.

In a particular embodiment, the elastic pressure-bearing block comprises a plurality of elastic jaws uniformly distributed circumferentially and a plurality of pressure-bearing blocks provided at ends of each of the elastic jaws, and the inner wall of the inner tube is provided with an accommodating cavity for accommodating the pressure-bearing block, and the elastic pressure bearing module is configured to throw a pressure-holding ball to seal with the pressure-bearing block and then hold pressure, and the pressure-bearing block moves down to the accommodating cavity and radially expands outwards under the action of the elastic claw to allow the pressure-holding ball to pass through.

In a particular embodiment, a rubber plug assembly is connected below the inner tube, and the pressure-holding ball falls to the rubber plug assembly after passing through the elastic pressure-bearing module and forms a seal.

In a particular embodiment, the first outer tube has a through hole for passing through the stopping block which has a larger cross-sectional circumferential dimension than the stopping block, and the second torque-transmitting mechanism has a through hole for slidably engaging the first torque-transmitting mechanism which has a larger cross-sectional circumferential dimension than the first torque-transmitting mechanism, thereby configuring the inner tube to rotate the stopping block relative to the first hydraulic cylinder within an angle range,

    • an exposing hole is formed in the first hydraulic cylinder, and by means of reverse rotation, the inner tube can push the stopping block to rotate to correspond to the exposing hole, so that the stopping block is separate from the first hydraulic cylinder and no longer abutting the first hydraulic cylinder.

In a particular embodiment, the liner hanger further comprises a second hydraulic cylinder provided with a through hole in which a radially inwardly extending resilient biasing means is provided, and the resilient biasing means is configured to form a unidirectional rotational connection with the liner.

In a particular embodiment, the resilient biasing mechanism comprises a plunger and the liner includes a recess which is progressively deeper in a circumferential direction and terminates in a stopping portion, and the abutment of the liner with the second hydraulic cylinder is formed by the plunger abutting the stopping portion.

In a particular embodiment, the liner hanger further comprises a second hydraulic cylinder, wherein the second hydraulic cylinder is provided with an upper working surface and a lower working surface with the same pressure difference, and the lower end of the inner tube is connected with a rubber plug assembly, and the rubber plug assembly is located between the two working surfaces of the second hydraulic cylinder, and after the pressure-holding ball is in sealing fit with the rubber plug assembly, the two working surfaces of the second hydraulic cylinder can be separated.

In a particular embodiment, the rubber plug assembly comprises:

    • a rubber plug body;
    • a rubber plug cup and a sealing element which are arranged on the outer wall of the rubber plug body, wherein the sealing element is positioned above the rubber plug cup, and the rubber plug body is configured to separate the rubber plug cup from the sealing element; and
    • a ball seat sliding sleeve which is arranged inside the rubber plug body by means of a pin.

In a particular embodiment, the rubber plug body comprises a first body and a second body, and an elastic member is arranged on the upper portion of the second body, and an inner sliding sleeve is arranged inside the second body by means of a shearing pin for preventing the elastic member to contract radially, and the upper portion of the elastic member extends to the inside of the first body and is in snap-fit with the first body under the action of the radial abutment of the inner sliding sleeve.

In a particular embodiment, the rubber plug cup is made of vulcanized rubber.

Compared with the conventional liner hangers, the application has the following advantages.

In the operation of a liner running into the well, the liner hanger can release jamming in a rotating mode, and the releasing procedure is arranged before well cementing, thereby reducing the risk of releasing failure. In addition, after the liner hanger is released, the torque can still be transmitted between the inner tube and the outer tube assembly, so that the torque of the inner tube is transmitted to the liner through the first outer tube, the second outer tube, the hanger body and the like in sequence, and the well cementing quality can be improved in a rotating manner during the cementing operation.

Meanwhile, the liner hanger can also use a high flow rate circulation mode for de-jamming. The first hydraulic cylinder and the second hydraulic cylinder of the liner hanger are not influenced by the pressure of circulating liquid in the operation of large-displacement de-jamming, so that the condition of releasing prematurely or hanging prematurely is avoided.

The liner hanger has a plurality of modes in the releasing operation, one mode is that the first hydraulic cylinder works normally, so that the stopping block can be separated from the inner tube, and thereby the subsequent releasing operation is completed. Another mode is that, when the first hydraulic cylinder cannot work normally, the stopping block can correspond to the exposing hole in the first hydraulic cylinder by the operation of reversely rotating the inner tube, so that the stopping block can be separated from the inner tube. The two modes exist simultaneously, and the risk of releasing failure is further reduced.

In addition, the second hydraulic cylinder for pushing the slips is provided with an upper working surface and a lower working surface with the same pressure difference, so that the second hydraulic cylinder is prevented from working prematurely to push the slips during the drilling fluid circulating operation.

BRIEF DESCRIPTION OF THE FIGURES

The present application will be described below with reference to the accompanying drawings.

FIG. 1 shows a schematic view of an upper half of one embodiment of a liner hanger according to the present application;

FIG. 2 shows a schematic view of a lower half of one embodiment of a liner hanger according to the present application;

FIG. 3 shows a schematic view of one embodiment of a rubber plug assembly according to the present application;

FIG. 4 shows a schematic cross-sectional view A-A of FIG. 1 according to the present application;

FIG. 5 shows a schematic cross-sectional view B-B of FIG. 1 according to the present application;

FIG. 6 shows a schematic cross-sectional view C-C of FIG. 2 according to the present application;

FIG. 7 is a graph showing a liner hanger according to the present application during performance testing, wherein the x-axis represents time and the y-axis represents pressure; and

FIG. 8 shows a graph of a rubber plug system useful in a liner hanger according to the present application during performance testing, wherein the x-axis represents time and the y-axis represents pressure.

In the figures, the reference numbers are as follows: 1 outer tube assembly; 2 inner tube; 3 torque transfer assembly; 4 locking assembly; 5 lower joint; 6 rubber plug assembly; 11 first outer tube; 12 second outer tube; 31 torque strip; 32 torque block; 33 transmission nut; 34 reverse-thread nut; 35 stopping portion; 36 bearing assembly; 37 anti-rotation nail; 41 first hydraulic cylinder; 42 stopping block; 43 elastic pressure-bearing module; 44 locking ring; 411 exposing hole; 431 elastic claw; 432 pressure-bearing block; 433 accommodating cavity; 61 rubber plug body; 62 rubber plug cup; 63 ball seat sliding sleeve; 64 elastic member; 65 inner sliding sleeve; 611 first body; 612 second body; 71 second hydraulic cylinder; 72 plunger; 73 plunger head; 8 liner; 81 recess; 82 stopping portion; 100 liner hanger.

In the present application, all drawings are schematic and serve only to illustrate the principles of the application, and are not drawn to scale.

DETAILED DESCRIPTION

The application is described below with reference to the accompanying drawings.

It should be noted that in the present application, the direction close to the wellhead is described as “up” or the like, and the direction away from the wellhead is described as “down” or the like. The term “axial” refers to the direction of the central axis of the outer tube assembly 1 and “radial” refers to the direction perpendicular to the “axial” direction. They are not intended to limit the absolute positions of the parts or components involved, but may vary from case to case.

For clarity of illustration, the liner hanger according to present application is divided into upper and lower portions which are shown in FIGS. 1 and 2, respectively, wherein FIG. 1 shows a schematic view of the upper half of one embodiment of a liner hanger 100 according to the present application, and FIG. 2 shows a schematic view of the lower half of one embodiment of a liner hanger 100 according to the present application.

In the prior art, the hanger comprises slips and a hydraulic cylinder, and the hydraulic cylinder pushes the slips to expand so as to realize sitting and hanging, and the connection relationship between the slips and the hydraulic cylinder is not the key technical point of the application and is not described herein again.

As shown in FIG. 1, in addition to a hanger body, slips (not shown) and a second hydraulic cylinder 71 for pushing the slips, the liner hanger 100 of the present application further comprises an outer tube assembly 1, an inner tube 2, a locking assembly 4 and a torque transmitting assembly 3. The inner tube 2 is sleeved in the outer tube assembly 1.

The outer tube assembly 1 includes a first outer tube 11 and a second outer tube 12 which are axially inserted from top to bottom, and more specifically, the first outer tube 11 and the second outer tube 12 are connected in a spline or tooth-engaged connection manner in the embodiment but not limited thereto, as long as the first outer tube and the second outer tube can move relative to each other in the axial direction and can transmit axial torque. The lower portion of the second outer tube 12 is connected to the hanger body, and torque can be transmitted therebetween.

The upper end of the first outer tube 11 is connected to the inner tube 2 by a locking assembly 4. The locking assembly 4 is fixedly connected with the inner tube 2 by means of a shearing pin. In the initial state, i.e. the state shown in FIG. 1, the locking assembly 4 is able to prevent the inner tube 2 from moving downwards relative to the outer tube assembly 1.

In one particular embodiment, the locking assembly 4 includes a first hydraulic cylinder 41 and a stopping block 42. As shown in FIG. 1, the first hydraulic cylinder 41 is sleeved outside the inner tube 2 by means of a shearing pin and is positioned above the first outer tube 11. A stepped part at the top of the first outer tube 11 extends to the inside of the first hydraulic cylinder 41, i.e., the lower end of the first hydraulic cylinder 41 has a portion overlapping the top of the first outer tube 11. Preferably, the lower end of the first outer tube 11 forms an interlocking fit, for example a tooth-engaged connection, with the upper end of the second outer tube 12, so as to be circumferentially fixed and axially movable relative to each other and to be able to transmit torque axially and circumferentially. The stopping blocks 42 are provided in plural numbers, and are uniformly arranged on the wall of the first outer tube 11 along the circumferential direction. In this embodiment, four stopping blocks 42 are provided, each slidably arranged on the first outer tube 11 in a radial direction for passing therethrough. Two ends of the stopping block 42 are respectively in contact with the inner tube 2 and the first hydraulic cylinder 41, wherein the stopping block 42 is inserted into the inner tube 2 so that the inner tube 2 cannot move axially relative to the first outer tube 11. The stopping block 42 is in normal contacting relation with the first hydraulic cylinder 41, and the first hydraulic cylinder 41 is used for preventing the stopping block 42 from sliding out from the inner tube 2 in a radial outward direction.

According to the present application, a ramp is provided at a position where the stopping portion 42 contacts the inner tube 2, so that the stopping block 42 can be pushed to move radially outward when the inner tube 2 moves downward with respect to the first outer tube 11. The ramp may be provided on the inner tube 2 or on the stopping block 42. When the stopping block 42 is stopped by the first hydraulic cylinder 41, the stopping block 42 cannot move radially outward, and the downward movement of the inner tube 2 inevitably pushes the first outer tube 11 moving downward together with the inner tube 2. When the stopping block 42 is no longer stopped by the first hydraulic cylinder 41, the inner tube 2 can be moved downward relative to the first outer tube 11, pushing the stopping block 42 radially outward, thereby disengaging the second torque transmitting mechanism (e.g., torque block) 32 from the first torque transmitting mechanism (e.g., torque strip) 31, thereby the hanger can be released by rotating the first outer tube 11. That is, in the present application, the stopping block 42 can play both a role of keying to lock the inner tube 2 and the first outer tube 11 to each other so that they are fixed and a role of unlocking the connection between the inner tube 2 and the first outer tube 11 so as to facilitate release of the hanger by rotating the first outer tube 11 in emergency.

According to the present application, the locking assembly 4 further comprises an elastic pressure-bearing module 43 disposed inside the inner tube 2 by a shearing pin. A channel communicating the first hydraulic cylinder 41 with the inner cavity of the inner tube 2 is disposed in the tube wall of the inner tube 2, and in an initial state, the elastic pressure-bearing module 43 seals the channel. The elastic pressure-bearing module 43 can move only after being sealed and pressure-held by the pressure-holding ball, so that the elastic pressure-bearing module 43 cannot move even if the circulating displacement capacity of the drilling fluid is large during the operation of de-jamming by adopting a large-displacement circulation, and thereby the first hydraulic cylinder 41 will not be pushed to work. Therefore, the application can adapt to the circulation of drilling fluid with high flow rate. Due to the structural characteristics, in case of large-displacement drilling fluid circulation in prior art, accidents such as releasing or releasing prematurely can happen.

Specifically, the elastic pressure-bearing module 43 includes a plurality of elastic claws 431 uniformly distributed in the circumferential direction and a plurality of pressure-bearing blocks 432 provided at the ends of each of the elastic claws 431. In one embodiment of the application, the elastic claw is an aluminum alloy elastic claw. In an initial state, the plurality of pressure-bearing blocks 432 enclose a closed annulus, and the outer wall of the annulus is sealed with the inner wall of the inner tube 2, and the inner wall of the annulus can be engaged with a pressure-holding ball to form a sealed connection structure. The inner wall of the inner tube 2 is provided with an accommodating cavity 433 for accommodating the pressure-bearing block 432, and the accommodating cavity 433 is located below the pressure-bearing block 432. After the pressure-holding ball is thrown in and sealed with the pressure-bearing block 432, then the pressure therein is held, and the pressure-bearing block 432 moves downwards to the accommodating cavity 433 and expands outwards in the radial direction under the action of the elastic claw 431. After the pressure-bearing block 432 moves downwards, the channel for communicating the inner cavity of the inner tube 2 with the first hydraulic cylinder 41 is opened, and meanwhile, after the pressure-bearing block 432 expands to the accommodating cavity 433, the channel therebetween is expanded, so that the pressure-holding ball passes through.

In a particular embodiment, a locking ring 44 is also provided between the first hydraulic cylinder 41 and the inner tube 2. The locking ring 44 is fixedly connected with the inner tube 2, and the first hydraulic cylinder 41 is fixedly connected with the locking ring 44 by means of a shearing pin. Sealing elements are respectively arranged between the locking ring 44 and the first hydraulic cylinder 41 and between the locking ring 44 and the inner tube 2, and the two sealing elements seal the working surface of the first hydraulic cylinder 41 and a channel which communicates with the inner cavity of the inner tube 2 together. Thereby, the pressure in the inner cavity of the inner tube 2 can be transmitted to the working surface of the first hydraulic cylinder 41, so that the first hydraulic cylinder 41 can move upward.

According to the invention, a rubber plug assembly 6 is connected and arranged below the inner tube 2, and the pressure-holding ball falls to the rubber plug assembly 6 after passing through the elastic pressure-bearing module 43 and seals against the rubber plug assembly 6.

Specifically, as shown in FIG. 3, the rubber plug assembly 6 includes a rubber plug body 61, a rubber plug cup 62 disposed on the outer wall of the rubber plug body 61, and a ball seat sliding sleeve 63 disposed inside the rubber plug body 61 by means of a pin. By means of such arrangement, on one hand, the ball seat sliding sleeve 63 can be engaged with a pressure-holding ball, so that pressure holding is facilitated after sealing is formed, and therefore the first hydraulic cylinder 41 is pushed to work. On the other hand, the rubber plug assembly 6 can move downwards during the subsequent operation, so that the rubber plug cup 62 plays a role in cleaning the tube wall.

In one specific embodiment, the rubber plug body 61 comprises a first body 611 and a second body 612. The upper end of the first body 611 is connected with the lower joint 5 by a joint or other downhole connection tools, and a seal (such as a sealing element) for sealing with the hanger body is provided at the maximum outer diameter of the first body 611. An elastic member 64 is fixedly disposed on an upper portion of the second body 612, and an upper end of the elastic member 64 is in a radially contracted state without an external force exerted on the elastic member 64. In the present embodiment, the upper end of the elastic member 64 protrudes into the inside of the first body 611, and an inner sliding sleeve 65 is disposed inside the elastic member 64 and abuts against the upper end of the elastic member 64 so that the upper end will not radially contract. At this time, the upper end of the elastic member 64 is fixedly connected to the first body 611 in a snap-fit manner. In one embodiment of the present invention, the first body 611 takes the form of a D-ring, wherein the sealing element is a polymeric sealing element capable of withstanding a high temperature and high pressure sealing at a gap of about 2 to 4 mm.

According to the present invention, the inner sliding sleeve 65 is connected to the second body 612 by means of shearing pin(s). The inner sleeve 65 is moved downward after shearing the shearing pin(s), and gets rid of the abutting state with the elastic member 64, whereby the elastic member is radially contracted to get rid of the fixed connection state with the first body 611. The second body 612 with the rubber plug cup 62 can now be separated from the first body 611 with the sealing element. By means of such arrangement, after first body 611 with the sealing element and the second body 612 with rubber plug cup 62 are separated, second body 612 with rubber plug cup 62 moves along the tube, scrapes and cleans the inner wall of the tube. Because the rubber plug cup 62 is comparatively soft in material, and preferably is made of vulcanized rubber, the rubber plug cup 62 can realize scraping effectively and can adapt to the tubes in different tube diameters to a certain extent simultaneously, and adaptability is stronger.

The torque transfer assembly 3 is disposed between the outer tube assembly 1 and the inner tube 2 and includes a torque strip 31, a torque block 32, a transmission nut 33 and a reverse-thread nut 34.

Wherein the torque strip 31 is in a strip shape and is fixedly arranged on the outer wall of the inner tube 2. Specifically, a groove engaging with the torque strip 31 is arranged on the outer wall of the inner tube 2. The torque strip 31 is embedded into the groove on the outer wall of the inner tube 2, and the thickness of the torque strip 31 is larger than the depth of the groove.

The torque block 32 is fixedly arranged on the inner wall of the first outer tube 11, and specifically, by arranging a groove engaging with the torque block 32 on the inner wall of the first outer tube 11, the torque block 32 is embedded into the groove, and the torque block 32 and the first outer tube 11 can also be fixedly connected by means of the radially arranged anti-rotation nails 37, as shown in FIG. 5.

In the initial state, the torque block 32 and the torque strip 31 are engaged with each other by means of a sliding connection. As shown in FIG. 1, the torque block 32 is located at the uppermost portion of the torque strip 31, and specifically, in the present embodiment, the upper end edge of the torque block 32 is flush with the upper end edge of the torque strip 31.

The inner and outer walls of the transmission nut 33 are in contact with the inner tube 2 and the first outer tube 11, respectively. Wherein the transmission nut 33 is engaged with the torque strip 31 on the inner tube 2 by means of an axially sliding connection. The transmission nut 33 is engaged with the first outer tube 11 by means of a screw connection. When the inner tube 2 pushes the transmission nut 33 to rotate, the threads between the transmission nut 33 and the first outer tube 11 cause the transmission nut 33 to move axially relative to the first outer tube 11. In the present embodiment, when the transmission nut 33 is moved axially downward relative to the first outer tube 11, the rotational direction of the inner tube 2 is defined as forward rotation or rotating forward.

A stopping portion 35 is provided on the inner wall of the first outer tube 11, and the stopping portion 35 is located below the transmission nut 33. The transmission nut 33 can abut against the upper end surface of the stopping portion 35 after moving downward a distance with respect to the first outer tube 11.

Meanwhile, a bearing assembly 36 is further provided between the first outer tube 11 and the inner tube 2. A stepped part of reduced size is provided at the top of the first outer tube 11 to prevent the bearing assembly 36 from coming out. The bearing assembly 36 is fitted over the inner tube 2 without affecting the relative axial movement between the first outer tube 11 and the inner tube 2. In this way, a supporting effect is provided by the bearing assembly 36 when the inner tube 2 is rotated relative to the first outer tube 11, ensuring that the central axes of the inner tube 2 and the first outer tube 11 are always coincident.

The inner and outer walls of the reverse-thread nut 34 are in contact with the inner tube 2 and the second outer tube 12, respectively. Wherein the reverse-thread nut 34 is fitted with the torque strip 31 on the inner tube 2 in an axial sliding connection manner. The reverse-thread nut 34 is engaged with the second outer tube 12 by a threaded connection. The thread-rotating direction between the reverse-thread nut 34 and the second outer tube 12 is opposite to the thread-rotating direction between the transmission nut 33 and the first outer tube 11. That is, when the inner tube 2 is rotating forward, the transmission nut 33 and the reverse-thread nut 34 are pushed to rotate by means of the torque strip 31, and the transmission nut 33 moves axially downward relative to the first outer tube 11, and the reverse-thread nut 34 moves axially upward relative to the second outer tube 12.

In a particular embodiment, a lower joint 5 is provided at the lower end of the inner tube 2, the lower joint 5 having an outer diameter larger than the outer diameter of the inner tube 2. As shown in FIG. 1, in the initial state, the lower end surface of the reverse-thread nut 34 abuts against the upper end surface of the lower joint 5. With this arrangement, the inner tube 2 cannot move upward relative to the second outer tube 12 at this time, because the reverse-thread nut 34 and the second outer tube 12 are connected to each other by the threads and the lower end surface of the reverse-thread nut 34 abuts against the lower joint 5.

The thread on the inner wall of the second outer tube 12 for engaging with the reverse-thread nut 34 is distributed only on the lower half of the second outer tube 12, and the upper half of the second outer tube 12 has no thread and is a smooth wall surface. Specifically, the length of the portion of the second outer tube 12 without threads is greater than the height of the threads of the reverse-thread nut 34. After the reverse-thread nut 34 is moved upward relative to the second outer tube 12 to be disengaged from the threaded connection, the reverse-thread nut 34 is released from the connection with the second outer tube 12. At this time, the inner tube 2 can move upward relative to the second outer tube 12, and at the same time, during the moving upward of the inner tube 2, the lower joint 5 abuts against the reverse-thread nut 34, and the reverse-thread nut abuts against the first outer tube 11, so that the first outer tube 11 can move up together with the inner tube 2, and the releasing is completed.

In a preferred embodiment of the present invention, the second hydraulic cylinder 71 is provided with two upper and lower working surfaces (not shown) having the same differential pressure and opposite directions. As shown in FIG. 2, the rubber plug assembly 6 which is disposed at the lower end of the inner tube 2 is located between two differential pressure working surfaces of the second hydraulic cylinder 71, and specifically, the sealing element of the rubber plug assembly 6 which is located at the maximum outer diameter of the first body 611 is located between the two differential pressure working surfaces. After the pressure-holding ball is in sealing fit with the rubber plug assembly 6, two working surfaces of the second hydraulic cylinder 71 can be separated. With the arrangement, as long as the rubber plug assembly 6 is not sealed, the upper and lower differential pressure working surfaces of the second hydraulic cylinder 71 can be subjected to the same pressure, so that the second hydraulic cylinder 71 is kept balanced, and the hanger is prevented from being hung prematurely due to the fact that the second hydraulic cylinder 71 moves prematurely during the drilling fluid circulation operation. Only when the rubber plug assembly 6 and the pressure-holding ball form sealing and the two pressure difference working surfaces of the second hydraulic cylinder 71 are stressed differently, the second hydraulic cylinder 71 starts to move to push the slips to finish hanging. Therefore, under the drilling fluid circulation working condition of high flow rate, as long as the rubber plug assembly 6 does not form a seal with the pressure-holding ball, the liner hanger will not be hung prematurely.

FIG. 6 shows a schematic cross-sectional view C-C of FIG. 2 according to the present invention. In one embodiment of the invention, as shown in FIG. 6, said second hydraulic cylinder 71 is provided with a through hole near the upper end, in which through hole a resilient biasing means, preferably a plunger 72, is arranged, and said plunger 72 extends radially inwards, and said plunger 72 comprises a plunger head 73. In an embodiment of the invention, the plunger 72 is configured to form a unidirectional rotational connection with the liner 8. In the embodiment of the present invention, the liner 8 is disposed inside the second hydraulic cylinder 71, and the outer surface of the liner 8 is provided with a recess 81 extending in the circumferential direction. In a preferred embodiment of the invention, said recess 81 becomes progressively deeper in the circumferential direction, ending in a stopping portion 82. The plunger 72 is configured to extend into the recess 81 and form an abutment of the liner 8 with the second hydraulic cylinder 71 by the plunger head 73 abutting the stopping portion 82. In the embodiment shown in FIG. 6, the second hydraulic cylinder 71 is able to rotate with the liner 8 in a counter-clockwise direction, preventing a sudden release of torque during the rotary running of the liner, thus avoiding the risk of releasing prematurely. That is, in the present invention, the plunger 72 and the recess 81 are provided to allow only one-way rotation, thereby releasing prematurely is prevented.

The working principle of the invention is as follows.

The liner hanger of the present application is run into the well as shown in FIGS. 1 and 2. During the operation of running the liner hanger into the well, the inner tube 2 can be rotated so that the inner tube 2 rotates forward, and the torque strip 31 and the torque block 32 are in cooperation to cause the first outer tube 11 to rotate forwards along with the inner tube 2. Since the second outer tube 12 and the first outer tube 11 are connected by means of a tooth-engaged connection, the first outer tube 11 will push the second outer tube 12 to rotate together with it, so that the entire liner hanger 100 will rotate, and de-jamming by the rotation will be finished.

After the liner hanger of the present application is run to the designed depth in the well, the pressure-holding ball is thrown into the liner hanger, and the pressure-holding ball is firstly engaged with the pressure-bearing block 432 to form sealing. After the pressure is held, the shearing pin for fixing the pressure-bearing block 432 is cut off, and the pressure-bearing block 432 moves downwards and radially expands to the accommodating cavity 433, and the pressure-holding ball falls into the ball seat sliding sleeve 63 of the rubber plug body 61 to form sealing again.

Then continuing to hold the pressure, wherein the rubber plug body 61 is provided with a hole for communicating the inner cavity of the rubber plug body with the upper differential pressure working surface of the second hydraulic cylinder 71, thus the second hydraulic cylinder 71 cuts off a shearing pin for connection and starts to move, and the slips are pushed to move to finish the sitting and hanging. The first hydraulic cylinder 41 then shears off the shearing pin which is connected to the locking ring 44 and moves upwardly so as to no longer abut the stopping block 42. It will be readily appreciated that the strength of the shearing pin of the first hydraulic cylinder 41 and the strength of the shearing pin of the second hydraulic cylinder 71 are designed to allow the second hydraulic cylinder 71 to move first and then the first hydraulic cylinder 41 to move next, thereby allowing liner hanger according to the present invention to sit and hang prior to being released.

After the upward movement of the first hydraulic cylinder 41, the stopping block 42 is no longer prevented from moving radially outward. Since the sitting and hanging are completed, the second outer tube 12 connected to the hanger body and the first outer tube 11 tooth-engaged to the second outer tube 12 are in a state of being unable to move down. The inner tube 2 is now moved downwards and the stopping block 42 is pushed radially outwards by the inner tube 2, at the same time the torque strip 31 is moved downwards by the inner tube 2, so that the torque block 32 is disengaged from the torque strip 31.

Subsequently, the inner tube 2 is rotated forward, and the inner tube 2 pushes the transmission nut 33 and the reverse-thread nut 34 to rotate forward by means of the torque strip 31. By the effects of the threads of the inner walls of the first outer tube 11 and the second outer tube 12, the transmission nut 33 is axially moved downwards with respect to the first outer tube 11 and the reverse-thread nut 34 is axially moved upwards with respect to the second outer tube 12. After the reverse-thread nut 34 moves upward to disengage from the second outer tube 12, the inner tube 2 can move upward relative to the second outer tube 12, separating from the second outer tube 12, and completing the releasing operation.

In order to keep the inner tube 2 still pushing the second outer tube 12 to rotate during the well cementing operation, the inner tube 2 is rotated forward continuously under the condition that the first outer tube 11 is kept in tooth-engagement with the second outer tube 12, so that the transmission nut 33 moves to abut against the stopping portion 35 on the inner wall of the first outer tube 11. At this time, if the inner tube 2 continues to rotate forward, it can only push the first outer tube 11 to rotate together. Therefore, in the operation of keeping the first outer tube 11 and the second outer tube 12 in tooth-engagement, the inner tube 2 is continuously rotated forward, so that the second outer tube 12 can be pushed to rotate together, and the rotation in the cementing operation is facilitated, and the well cementing quality is improved.

According to the present invention, in a preferred embodiment, as shown in FIGS. 1 and 4, the first hydraulic cylinder 41 is provided with an exposing hole 411, and by rotating in the opposite direction, the inner tube 2 can push the stopping block 42 to rotate to correspond to the exposing hole 411. When the first hydraulic cylinder 41 fails by accident and cannot move upward, the stopping block 42 may be disengaged from the abutment with the first hydraulic cylinder 41 by rotating the stopping block 42 to correspond to exposing hole 411 via rotating the inner tube 2 in the reverse direction. At this time, releasing in emergency can be realized, as described herein.

Specifically, as shown in FIGS. 4 and 5, the first outer tube 11 has a through-hole for the stopping block 42 passing through, and the through-hole has a cross-sectional circumferential dimension larger than that of the stopping block 42, and through holes of the torque block 32, the transmission nut 33 and the reverse-thread nut 34 for sliding fit with the torque strip 31 have larger circumferential dimensions than that of the torque strip 31, so that the inner tube 2 is configured to push the stopping block 42 to rotate in an angle range relative to the first hydraulic cylinder 41. In the initial state, the stopping block 42 is in circumferential contact with the first outer tube 11, and at the same time the torque strip 31 is in circumferential contact with the torque block 32, the transmission nut 33 and the reverse-thread nut 34, and all the contacts are on the same side. For example, when the inner tube 2 rotates forward, the torque strip 31 can directly push the torque block 32, the transmission nut 33 and the reverse-thread nut 34 to rotate, and at the same time, the inner tube 2 directly pushes the first outer tube 11 to rotate by means of the stopping block 42, and at this time, there is no rotation margin. When the inner tube 2 is reversed rotating, and because there is a rotational margin on this side, the stopping block 42 will be brought into circumferential contact with the first outer tube 11 only after the inner tube 2 has been rotated by a certain angle by the stopping block 42, and so does the relationship of the torque strip 31 with the torque block 32, the transmission nut 33 and the reverse-thread nut 34. That is, the inner tube 2 can be rotated within a certain reverse rotation angle to rotate the stopping block 42 to correspond to the exposing hole 411 without transmitting torque to the outer tube assembly 1, so that the stopping block 42 can be radially separated from the inner tube 2.

The subsequent releasing operation is the same as the releasing operation in the working principle of the invention, and is not described again here.

FIG. 7 shows a graph of the liner hanger 100 during performance testing according to the present invention, wherein the x-axis represents time and the y-axis represents pressure. FIG. 8 shows a graph of a rubber plug system that may be used with the liner hanger 100 according to the present invention during performance testing, wherein the x-axis represents time and the y-axis represents pressure. In the embodiment of the invention, through performance testing, the rotary torque of the liner hanger during the working operation is as high as 33 kN·m, and the well-entering releasing is normally finished, and the operation requirement of rotating the liner in the liner running operation is met. At about 200 seconds, the liner hanger achieves sitting and hanging at a pressure of about 10 MPa, as shown in FIG. 7. Then, at about 345 seconds, under a pressure of about 20 MPa, the pressure-bearing block 432 moves down to the accommodating cavity 433, and expands radially outward under the action of the elastic claw 431, so that the pressure-holding ball passes through, and the ball seat is pressed through and expanded.

In FIG. 8, performance testing experiments show that, the sealing performance of the rubber plug assembly 6 according to the invention reaches 25 MPa at 244° C., and various actions such as ball seat shearing, rubber plug compounding and the like are normally performed; the anti-early-sitting-hanging mechanism is applied for more than 200 wells on site, and the phenomenon of early-sitting-hanging does not occur.

Therefore, the performance testing proves that, the adoption of the liner hanger disclosed by the invention is not only beneficial to the efficient and quick running of the liner, but also can realize high flow rate circulation in the running operation of the liner, effectively realize de-jamming by rotating the liner hanger and prevent the liner hanger from being hung prematurely.

In the embodiment of the present invention, the following technical solutions may be included.

According to an aspect of the present invention, there is provided a liner hanger comprising a hanger body, the liner hanger further comprising:

    • an outer tube assembly 1 which comprises a first outer tube 11 and a second outer tube 12 which are axially inserted into each other, and the second outer tube 12 is connected with the hanger body;
    • an inner tube 2 which is sleeved inside the outer tube assembly 1; and
    • a torque transfer assembly 3 which is disposed between said outer tube assembly 1 and said inner tube 2, said torque transfer assembly 3 comprising:
    • a first torque transmitting mechanism 31 which is fixedly provided on an outer wall of the inner tube 2;
    • a second torque transmitting mechanism 32 which is fixedly disposed on an inner wall of the first outer tube 11, the second torque transmitting mechanism 32 being axially slidably engaged with the first torque transmitting mechanism 31;
    • a transmission nut 33 and a reverse-thread nut 34 which are axially slidably engaged with the first torque transmitting mechanism 31, the transmission nut 33 and the reverse-thread nut 34 having outer peripheries threadedly connected to the first outer tube 11 and the second outer tube 12, respectively, wherein a thread-rotating direction between the reverse-thread nut 34 and the second outer tube 12 is opposite to a thread-rotating direction between the transmission nut 33 and the first outer tube 11, and the inner tube is configured to be capable of rotating forward, thereby moving the reverse-thread nut upward to be disengaged from the second outer tube.

By means of the liner hanger according to the invention, the torque transmitting assembly utilizes a key slot matching principle to transmit torque, and a high-bearing rotary feeding function is realized, and releasing is reliably realized by rotating the liner hanger. That is, by rotating the inner tube 2 forward so that the reverse-thread nut 34 moves upward to disengage with the second outer tube 12, the inner tube 2 can move upward with respect to the second outer tube 12, and disengage with the second outer tube 12, and the releasing operation is completed.

In the liner hanger according to the present invention, the first torque-transmitting mechanism 31 is a torque strip preferably disposed in a groove on the outer wall of the inner tube, and the second torque-transmitting mechanism 32 is a torque block preferably disposed in a groove on the inner wall of the first outer tube.

In the liner hanger according to the present invention, a stopping portion 35 is provided inside the first outer tube 11, and in the releasing operation, the inner tube 2 is rotated relative to the outer tube assembly 1 to disengage the reverse-thread nut 34 from the thread of the second outer tube 12, so that the inner tube 2 can move up relative to the second outer tube 12, thereby completing the releasing operation; at the same time, the transmission nut 33 moves to abut against the stopping portion 35, so that torque is continuously transmitted between the first outer tube 11 and the inner tube 2.

By means of the liner hanger according to the invention, torque is transmitted by using a key slot matching principle, and a high-bearing rotary feeding function is realized, and releasing is reliably realized by rotating the liner hanger. After the release is completed, torque can still be transmitted between the inner tube and outer tube assemblies, and torque is transmitted from the inner tube to the outer tube assembly and then to the liner, thereby improving the well cementing quality in a rotational manner.

In the liner hanger according to the present invention, in the initial state, the lower end of the reverse-thread nut 34 is axially abutted against the inner tube 2, and the upper portion of the inner wall of the second outer tube 12 is a smooth wall surface for providing a moving space for the reverse-thread nut 34 to be disengaged from the inner wall thread of the second outer tube 12.

In the liner hanger according to the present invention, a lower joint 5 is provided at the lower end of the inner tube 2, and the outer diameter of the lower joint 5 is larger than the outer diameter of the inner tube 2, and the lower end of the reverse-thread nut 34 axially abuts against the upper end surface of the lower joint 5 in the initial state.

In the liner hanger according to the present invention, the liner hanger further comprises a locking assembly 4 for preventing downward movement of the inner tube 2 relative to the outer tube assembly 1 in an initial state, the locking assembly 4 comprising:

    • a first hydraulic cylinder 41 arranged on the outer wall of the inner tube 2 by means of a shearing pin, wherein the top of the first outer tube 11 is sleeved between the first hydraulic cylinder 41 and the inner tube 2; and
    • a stopping block 42 radially and slidably arranged on the top tube wall of the first outer tube 11 for passing therethrough, wherein in an initial state, one end of the stopping block 42 is inserted into the outer wall of the inner tube 2, and the other end of the stopping block 42 abuts against the first hydraulic cylinder 41.

By means of the liner hanger according to the invention, by employing a locking assembly comprising a stopping block, it can be reliably ensured that the inner tube and the first outer tube are axially fixed relative to each other, i.e. the inner tube and the first outer tube do not move axially relative to each other.

In the liner hanger according to the present invention, a ramp is provided at the junctions between the inner tube 2 and the stopping block 42. When the first hydraulic cylinder 41 no longer abuts against the stopping block 42 and the inner tube 2 moves downward relative to the first outer tube 11, the ramp can push the stopping block 42 radially outward from inside the inner tube 2.

With the liner hanger according to the present invention, the axial fixation between the inner tube 2 and the first outer tube 11 is gotten rid of by moving the stopping block 42 out of the inner tube 2. Thus, during normal operation, the release can be performed by rotating the first outer tube.

In the liner hanger according to the present invention, the locking assembly 4 further comprises an elastic pressure-bearing block 43 disposed inside the inner tube 2 by means of a shearing pin, and a channel communicating the first hydraulic cylinder 41 with the inner cavity of the inner tube 2 is disposed in the tube wall of the inner tube 2, and in an initial state, the elastic pressure-bearing block 43 seals the channel.

In the liner hanger according to the present invention, the elastic pressure-bearing module 43 comprises a plurality of elastic claws 431 uniformly distributed in the circumferential direction and a plurality of pressure-bearing blocks 432 arranged at the end portions of the elastic claws 431, and an accommodating cavity 433 for accommodating the pressure-bearing blocks 432 is arranged on the inner wall of the inner tube 2, and the elastic pressure-bearing module 43 is configured to throw a pressure-holding ball to seal with the pressure-bearing blocks 432 to hold the pressure, and then the pressure-bearing blocks 432 move downwards to the accommodating cavity 433 to expand radially outwards under the action of the elastic claws 431, so that the pressure-holding ball passes through.

In the liner hanger according to the present invention, a rubber plug assembly 6 is connected below the inner tube 2, and the pressure-holding ball falls to the rubber plug assembly 6 after passing through the elastic pressure-bearing module 43, and forms a seal.

In the liner hanger according to the present invention, the first outer tube 11 has a through-hole for the stopping block 42 passing through, and the through-hole has a cross-sectional circumferential dimension larger than that of the stopping block 42, and the second torque transmitting mechanism 32 has a through-hole for the first torque transmitting mechanism 31 passing through, and the through-hole has a cross-sectional circumferential dimension larger than that of the first torque transmitting mechanism 31, so that the inner tube 2 is configured to rotate the stopping block 42 relative to the first hydraulic cylinder 41 within a certain angular range.

The first hydraulic cylinder 41 is provided with an exposing hole 411, and by the reverse rotation, the inner tube 2 can push the stopping block 42 to rotate to correspond to the exposing hole 411, so that the stopping block 42 is disengaged from the abutment of the first hydraulic cylinder 41.

By means of the liner hanger according to the present invention, when the first hydraulic cylinder cannot move upwards by accident, the stopping block can rotate to the position corresponding to the exposing hole by means of reversely rotating the inner tube, and emergency releasing is achieved.

In the liner hanger according to the present invention, the liner hanger also includes a second hydraulic cylinder having a through hole, wherein a radially inwardly extending resilient biasing mechanism is disposed in the through hole, and the resilient biasing mechanism is configured to form a unidirectional rotational connection with the liner.

In the liner hanger according to the present invention, the resilient biasing mechanism comprises a plunger, and the liner comprises a recess gradually deepened in a circumferential direction and terminating in a stopping portion, abutment of the liner with the second hydraulic cylinder being formed by abutment of the plunger against the stopping portion.

By means of the liner hanger according to the present invention, only one-way rotation is allowed by the resilient biasing mechanism, thereby achieving a function of preventing early releasing.

In the liner hanger according to the present invention, the liner hanger further comprises a second hydraulic cylinder, and the second hydraulic cylinder is provided with an upper working surface and a lower working surface with the same pressure difference, and the lower end of the inner tube 2 is connected with a rubber plug assembly 6, and the rubber plug assembly 6 is positioned between the two working surfaces of the second hydraulic cylinder, and the two working surfaces of the second hydraulic cylinder can be separated after a pressure-holding ball is in sealing fit with the rubber plug assembly 6.

In the liner hanger according to the present invention, the rubber plug assembly comprises:

    • a rubber plug body 61;
    • a rubber plug cup 62 and a sealing element arranged on the outer wall of the rubber plug body 61, wherein the sealing element is positioned above the rubber plug cup 62, and the rubber plug body 61 is configured to separate the rubber plug cup 62 from the sealing element;
    • a ball seat sliding sleeve 63 arranged in the rubber plug body 61 by means of a pin.

By means of the liner hanger according to the present invention, the rubber plug cup and the sealing element are separated by the rubber plug assembly located between the two working surfaces of the second hydraulic cylinder, so that the sealing function and the isolation wiping function are separated, and the sealing capability of the rubber plug assembly under a high-temperature condition is guaranteed.

In the liner hanger according to the present invention, the rubber plug body 61 comprises a first body 611 and a second body 612, and an elastic member 64 is disposed on the upper portion of the second body 612, and an inner sliding sleeve 65 for preventing the elastic member 64 to contract radially is disposed inside the second body 612 by means of a shearing pin, and the upper portion of the elastic member 64 extends into the first body 611, and is in snap-fit with the first body 611 under the radial abutment action of the inner sliding sleeve 65.

In the liner hanger according to the present invention, the rubber plug cup 62 is made of vulcanized rubber.

In the description of the present invention, it is to be understood that the terms “first”, “second”, and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to imply that the number of technical features indicated are in fact significant. Thus, a feature defined as “first” or “second” may explicitly or implicitly include one or more of those features. In the description of the present invention, “a plurality” means two or more unless specifically defined otherwise.

In the present application, unless expressly stated or limited otherwise, the terms “mounted,” “connected,” “secured,” and the like are to be construed broadly. For example, the connection may be fixed, detachable, or integrated; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening parts, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

In the description of the specification, reference to the description of “one embodiment,” “some embodiments,” “an example,” “a specific example,” or “some examples” or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the present invention in any way. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing examples, or that equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A liner hanger comprising a hanger body, wherein the liner hanger further comprises:

an outer tube assembly (1) which includes a first outer tube (11) and a second outer tube (12) axially inserted with each other, and the second outer tube (12) is connected with the hanger body;
an inner tube (2) which is sleeved inside the outer tube assembly (1); and
a torque transfer assembly (3) which is disposed between the outer tube assembly (1) and the inner tube (2), the torque transfer assembly (3) comprising: a first torque transmitting mechanism (31) which is fixedly arranged on an outer wall of the inner tube (2); a second torque transmitting mechanism (32) which is fixedly disposed on an inner wall of the first outer tube (11), and the second torque transmitting mechanism (32) is axially slidably engaged with the first torque transmitting mechanism (31); a transmission nut (33) and a reverse-thread nut (34) which are axially slidably engaged with the first torque transfer mechanism (31), and the outer peripheries of the transmission nut (33) and the reverse-thread nut (34) are threadedly connected to the first outer tube (11) and the second outer tube (12) respectively, wherein the thread-rotating direction between the reverse-thread nut (34) and the second outer tube (12) is opposite to the thread-rotating direction between the transmission nut (33) and the first outer tube (11), and the inner tube is configured to be capable of rotating forward, thereby moving the reverse-thread nut upward to disengage from the second outer tube.

2. The liner hanger according to claim 1, wherein the first torque transmitting mechanism (31) is a torque strip, and the torque strip is preferably disposed in a groove on the outer wall of the inner tube, and the second torque transmitting mechanism (32) is a torque block, and the torque block is preferably disposed within a groove on an inner wall of the first outer tube.

3. The liner hanger according to claim 1, wherein a stopping portion (35) is provided inside the first outer tube (11), and in the releasing operation, the inner tube (2) is rotated relative to the outer tube assembly (1) to disengage the reverse-thread nut (34) from the threads of the second outer tube (12), thereby allowing the inner tube (2) to move up relative to the second outer tube (12) to complete the releasing operation; at the same time, the transmission nut (33) moves to abut against the stopping portion (35), so that torque is continuously transmitted between the first outer tube (11) and the inner tube (2).

4. The liner hanger according to claim 1, wherein in an initial state, a lower end of the reverse-thread nut (34) axially abuts the inner tube (2), and an upper portion of an inner wall of the second outer tube (12) is a smooth wall surface for providing a moving space for the reverse-thread nut (34) to be disengaged from the threads on the inner wall of the second outer tube (12).

5. The liner hanger according to claim 4, wherein a lower joint (5) is provided at a lower end of the inner tube (2), and an outer diameter of the lower joint (5) is larger than an outer diameter of the inner tube (2), and a lower end of the reverse-thread nut (34) axially abuts an upper end face of the lower joint (5) in an initial state.

6. The liner hanger according to claim 1, any further comprising a locking assembly (4) for preventing downward movement of the inner tube (2) relative to the outer tube assembly (1) in an initial state, the locking assembly (4) comprising:

a first hydraulic cylinder (41) which is arranged on the outer wall of the inner tube (2) by means of a shearing pin, and the top of the first outer tube (11) is sleeved between the first hydraulic cylinder (41) and the inner tube (2); and
a stopping block (42) which is radially slidably arranged on the tube wall of the top of the first outer tube (11) for passing therethrough, and in an initial state, one end of the stopping block (42) is inserted into the outer wall of the inner tube (2), and the other end of the stopping block (42) is abutted against the first hydraulic cylinder (41).

7. The liner hanger according to claim 6, wherein a ramp is provided at the junction of the inner tube (2) and the stopping block (42) which is able to push the stopping block (42) radially outwards from inside of the inner tube (2) when the inner tube (2) moves downwards relative to the first outer tube (11) in case that the first hydraulic cylinder (41) no longer abuts the stopping block (42).

8. The liner hanger according to claim 7, wherein the locking assembly (4) further comprises an elastic pressure-bearing block (43) disposed inside the inner tube (2) by means of a shearing pin, and a channel communicating the first hydraulic cylinder (41) with the inner cavity of the inner tube (2) is provided in the tube wall of the inner tube (2), and the elastic pressure-bearing block (43) seals the channel in an initial state.

9. The liner hanger according to claim 8, wherein the elastic pressure-bearing block (43) comprises a plurality of elastic jaws (431) uniformly distributed circumferentially and a plurality of pressure-bearing blocks (432) provided at ends of each of the elastic jaws (431), and the inner wall of the inner tube (2) is provided with an accommodating cavity (433) for accommodating the pressure-bearing block (432), and the elastic pressure bearing module (43) is configured to throw a pressure-holding ball to seal with the pressure-bearing block (432) and then hold pressure, the pressure-bearing block (432) moves down to the accommodating cavity (433) and radially expands outwards under the action of the elastic claw (431) to allow the pressure-holding ball to pass through.

10. The liner hanger according to claim 9, wherein a rubber plug assembly (6) is connected below the inner tube (2), and the pressure-holding ball falls to the rubber plug assembly (6) after passing through the elastic pressure-bearing module (43) and forms a seal.

11. The liner hanger according to claim 6, wherein the first outer tube (11) has a through hole for the stopping block (42) passing through which has a larger cross-sectional circumferential dimension than the stopping block (42), and the second torque-transmitting mechanism (32) has a through hole for slidably engaging the first torque-transmitting mechanism (31) which has a larger cross-sectional circumferential dimension than the first torque-transmitting mechanism (31), thereby configuring the inner tube (2) to rotate the stopping block (42) relative to the first hydraulic cylinder (41) within an angle range,

an exposing hole (411) is formed in the first hydraulic cylinder (41), and by means of reverse rotation, the inner tube (2) can push the stopping block (42) to rotate to correspond to the exposing hole (411), so that the stopping block (42) is separate from the first hydraulic cylinder (41) and no longer abutting the first hydraulic cylinder (41).

12. The liner hanger according to claim 1, further comprising a second hydraulic cylinder provided with a through hole in which a radially inwardly extending resilient biasing means is provided, and the resilient biasing means is configured to form a unidirectional rotational connection with the liner.

13. The liner hanger of claim 12, wherein the resilient biasing mechanism comprises a plunger and the liner includes a recess which is progressively deeper in a circumferential direction and terminates in a stopping portion, and the abutment of the liner with the second hydraulic cylinder is formed by the plunger abutting the stopping portion.

14. The liner hanger according to claim 1, further comprising a second hydraulic cylinder, wherein the second hydraulic cylinder is provided with an upper working surface and a lower working surface with the same pressure difference, and the lower end of the inner tube (2) is connected with a rubber plug assembly (6), and the rubber plug assembly (6) is located between the two working surfaces of the second hydraulic cylinder, and after the pressure-holding ball is in sealing fit with the rubber plug assembly (6), the two working surfaces of the second hydraulic cylinder can be separated.

15. The liner hanger of claim 14, wherein the rubber plug assembly comprises:

a rubber plug body (61);
a rubber plug cup (62) and a sealing element which are arranged on the outer wall of the rubber plug body (61), wherein the sealing element is positioned above the rubber plug cup (62), and the rubber plug body (61) is configured to separate the rubber plug cup (62) from the sealing element; and
a ball seat sliding sleeve (63) which is arranged inside the rubber plug body (61) by means of a pin.

16. The liner hanger according to claim 15, wherein the rubber plug body (61) comprises a first body (611) and a second body (612), and an elastic member (64) is arranged on the upper portion of the second body (612), and an inner sliding sleeve (65) is arranged inside the second body (612) by means of a shearing pin for preventing the elastic member (64) to contract radially, and the upper portion of the elastic member (64) extends to the inside of the first body (611) and is in snap-fit with the first body (611) under the action of the radial abutment of the inner sliding sleeve (65).

17. The liner hanger according to claim 15, wherein the rubber plug cup (62) is made of vulcanized rubber.

Patent History
Publication number: 20260243152
Type: Application
Filed: Jan 3, 2024
Publication Date: Aug 20, 2026
Inventors: Zhen LI (Dezhou, Shandong), Huiqian YAO (Dezhou, Shandong), Zhaohui GUO (Dezhou, Shandong), Wenjun SUN (Beijing), Chao WANG (Dezhou, Shandong), Guoan ZHANG (Dezhou, Shandong), Fuping LI (Dezhou, Shandong), Minghui XU (Dezhou, Shandong), Xing XU (Dezhou, Shandong), Shengyu YAN (Dezhou, Shandong)
Application Number: 19/131,753
Classifications
International Classification: E21B 43/10 (20060101);