Liftable tail pipe suspension device and screen pipe inner insertion pipe completion pipe string

Abstract

The invention discloses a lifting type tail pipe hanging device which comprises a packing type tail pipe hanger, a lifting type tail pipe hanger and a lifting type tail pipe hanger, and the packing type tail pipe hanger is driven by hydraulic pressure to complete setting hanging and setting; the lifting type ball seat device is internally provided with a ball seat, and the upper end of the ball seat is connected with a feeding drilling tool through a hydraulic releasing feeding tool; wherein when the pressure building ball falls into the ball seat, the pressure in the pipe is increased, and when the pressure reaches a first set value, the packing type drilling liner hanger completes sitting hanging; when the pressure reaches a second set value, the hydraulic releasing feeding tool is separated from the ball seat, and releasing is completed; when the pressure reaches a third set value, the ball seat falls off, and circulation is re-established in the pipe; and after acid pickling is finished, the pipe column is lifted upwards, and then the setting packer is pressed downwards. By means of the method, the screen pipe well completion pickling operation process can be simplified, the problems that circulation between the screen pipe and the open hole section is not thorough, and the well wall is polluted are effectively solved, well completion transformation benefits are improved, and good economic benefits are achieved.

Description

Technical Field

[0001] The present invention relates to a retrievable liner hanger device and a completion string with an inner string inserted into a screen pipe, belonging to the field of oil and gas well completion. Background Art

[0002] Horizontal well screen pipe completion is widely promoted and applied in oilfields because of its simple completion process, less pollution to the reservoir, and low completion cost. However, during the drilling process, the filter cake easily formed on the wellbore wall by drilling mud can ensure the stability of the wellbore, but also cause pollution to the oil layer.

[0003] At present, during completion in China, the washing valve is mainly connected to the bottom of the screen pipe and lowered to the designed depth together, and the horizontal well washing and acid pickling plugging removal are carried out by using an external packer for sectional treatment in the screen pipe section. After completion, an acid pickling string composed of an inner string, an acid pickling packer, a drain valve, etc. needs to be lowered into the screen pipe, which cooperates with the external packer to divide the horizontal section into several sections, and the inner string is inserted into the washing valve on the screen pipe to form a washing channel. First, the packer is set by applying pressure, and then the acid liquid is made to flow between the screen pipe and the formation under the action of the packer by using the reverse circulation method, so as to achieve the purpose of acid pickling the open hole wellbore.

[0004] However, the entire string structure of the traditional screen pipe completion string is complex, and it is impossible to carry out normal circulation large-displacement well washing, and the circulation between the screen pipe and the formation is not thorough; the use of an external packer also increases the risk of string lowering and the construction cost is relatively high. Summary of the Invention

[0005] In view of the above technical problems existing in the prior art, the present invention provides a retrievable liner hanger device, which uses a single string to establish a circulating acid pickling channel for the screen pipe, integrates the liner hanger and the retrievable inner string structure, is connected with a drill string at the upper part, and connects the completion screen pipe and the inner string at the lower part, which can simplify the acid pickling operation process of the screen pipe completion, effectively solve the problems of incomplete circulation between the screen pipe and the open hole section and wellbore pollution, improve the completion transformation efficiency, and has good economic benefits.

[0006] The present invention also provides a completion string with an inner string inserted into a screen pipe.

[0007] According to one aspect of the present invention, a retrievable liner hanger device is provided, including: A packer-type liner hanger, which is set in place under the drive of hydraulic pressure; A packer-type liner hanger, which is set in place by first lifting the string and then pressing down the setting packer after acid pickling; A retrievable ball seat device, in which a ball seat is arranged, and the upper end of the ball seat is connected to a drill string through a hydraulic release tool; Among them, when the pressure-holding ball falls into the ball seat, the pressure inside the pipe increases. When the pressure reaches the first set value, the packer-type liner hanger is set in place; when the pressure reaches the second set value, the hydraulic release running tool separates from the ball seat to complete the release; when the pressure reaches the third set value, the ball seat falls off and the circulation inside the pipe is re-established. After the pickling is completed, first lift the pipe string, then press down to set the packer, and then continue to lift the pipe string to recover all the running tool and the inner insert pipe.

[0008] A further improvement of the present invention is that the packer-type liner hanger includes a packer unit and a hanger unit. The packer unit internally contains a setting stopper. By first lifting the pipe string, the outer diameter of the stopper extends out of the tie-back barrel, and then pressing down the pipe string, mechanical setting is completed. The hanger unit is set in place under the action of the internal pressure.

[0009] A further improvement of the present invention is that the retrievable ball seat includes a housing. The upper end of the housing is connected to the packer-type liner hanger, and the lower end is connected to the screen pipe. A further improvement of the present invention is that a ball seat joint assembly is provided inside the housing. The upper end of the ball seat joint assembly is connected to the ball seat by a shear pin. The shear pressure of the shear pin is the third set value, and the lower end of the ball seat joint assembly is connected to the inner insert pipe.

[0010] The housing and its internal components are respectively connected to the screen pipe and the inner insert pipe of the lower pipe string. In this embodiment, the outer side of the ball seat joint assembly is hermetically connected to the inner side of the housing to ensure that after the pressure-holding ball falls into the ball seat, the pressure-holding process will not affect the lower part of the ball seat, thereby ensuring that the packer-type liner hanger above the ball seat can be successfully set and hung, and the hydraulic release running tool can be successfully separated.

[0011] A further improvement of the present invention is that a tubing nipple is connected above the ball seat. The tubing nipple is connected to the hydraulic release running tool through a double-male coupling. Among them, a number of side holes for transmitting pressure are provided on the tubing nipple.

[0012] The side holes are used to transmit pressure. After the pressure-holding ball falls into the ball seat, the pressure inside the pipe can be transmitted to the outside of the drill string and the inside of the housing through the side holes, so as to act on the packer-type liner hanger above, and then drive the packer-type liner hanger to be set and hung.

[0013] A further improvement of the present invention is that the ball seat joint assembly includes an upper ball seat joint and a lower ball seat joint. A baffle is fixedly arranged between the upper ball seat joint and the lower ball seat joint. A number of flow holes are provided on the baffle for fluid circulation.

[0014] When the ball seat falls off when the pressure in the pipe reaches the third set value, the ball seat will move downward to the baffle position. Since the outer diameter of the ball seat is smaller than the diameter of the baffle, the ball seat will not block the entire baffle, and the flow holes on the baffle will not all be blocked. The fluid will flow through the flow holes, thereby establishing a circulation.

[0015] A further improvement of the present invention is that a compression cap is further provided on the ball seat upper joint. The compression cap is sleeved on the lower part of the short tubing joint, and the lower end of the short tubing joint is also connected to the ball seat upper joint through a universal shaft.

[0016] The ball seat upper joint includes a cylindrical upper joint body. The upper end of the joint body is provided with an inwardly contracting interface. The ball seat is installed on the interface and fixed by shear pins. A sealing assembly is provided between the outer wall of the upper joint body and the inner wall of the housing to ensure static sealing during the setting of the hanger, hydraulic release, and plugging through of the ball seat, and to prevent the communication between the liner and the lower pipe string and the annulus.

[0017] The lower end of the ball seat upper joint is connected to the upper end of the ball seat lower joint by threads.

[0018] The ball seat lower joint includes a cylindrical lower joint body. The lower end of the lower joint body is provided with a connection assembly for connecting the inner liner. A further improvement of the present invention is that a matching long and short casing is provided between the packer liner hanger and the housing of the retrievable ball seat device.

[0019] A further improvement of the present invention is that an internal telescopic pipe is provided at the lower part of the ball seat lower joint. The internal telescopic pipe can telescopically move within the lower joint, and the lower end of the internal telescopic pipe is connected to the inner liner.

[0020] A further improvement of the present invention is that a lifting short joint connected to the drill string is provided at the upper end of the hydraulic release running tool; a spline mechanism cooperating with the inner wall of the packer liner hanger is also provided on the hydraulic release running tool; The hydraulic release running tool is connected to the packer liner hanger through a ratchet mechanism.

[0021] According to another aspect of the present invention, a completion string for a screen inner liner is further provided, including: A liner hanger device; A screen and an inner liner provided at the lower end of the liner hanger device, and the inner liner is sleeved inside the screen; A guide shoe is provided below the inner liner; Wherein, the liner hanger device is the retrievable liner hanger device described above.

[0022] A further improvement of the present invention lies in that a plug is provided at the lower end of the inner insert pipe, the plug is inserted and matched with an insertion seat, and the insertion seat is connected to the guide shoe.

[0023] Compared with the prior art, the advantages of the present invention are as follows: For the retrievable liner hanger device according to the present invention, a screen circulation pickling channel is established by using a single string of pipe. The liner hanger and the retrievable inner insert pipe structure are integrally designed. The upper part is connected by a drill string, and the lower part connects the completion screen and the inner insert pipe, which can simplify the pickling operation process of screen completion, effectively solve the problems of incomplete circulation between the screen and the open hole section and wellbore pollution, improve the completion stimulation efficiency, and have good economic benefits.

[0024] The present invention adopts a mature packer-type liner hanger technology, and the setting, setting packer, and releasing performance are reliable.

[0025] The present invention adopts forward circulation well washing (pickling) to ensure thorough circulation between the screen and the open hole section. After the pipe string is lowered in place, first drop a pressure-holding ball to verify the setting and releasing and open the ball seat, then carry out forward pickling operation, and finally set the packer to meet the requirements of reservoir stimulation.

[0026] For the retrievable liner hanger device according to the present invention, the built-in telescopic pipe is allowed to move inside the lower joint of the ball seat, ensuring that when the hydraulic releasing running tool is screwed onto the inner insert pipe (oil pipe), there is continued downward threading space for the packer-type liner hanger body. When the built-in telescopic pipe is pushed up against the baffle, the drill string and the liner hanger can be appropriately pressed down to ensure that the thread connection between the built-in telescopic pipe at the lower end of the retrievable ball seat device and the inner insert pipe (oil pipe) is tightened. At the same time, during the well washing (pickling) operation, the built-in telescopic pipe is allowed to move up and down inside the lower joint of the ball seat, avoiding seal failure caused by pipe string movement due to factors such as pump pressure and displacement changes, thus affecting the well washing (pickling) effect.

[0027] After the pickling of the present invention is completed, first lift the pipe string, then press down to set the packer, and then continue to lift the pipe string, and the running tool and the inner insert pipe can be completely recovered. The operation is simple and the construction risk is reduced. The retrievable ball seat is connected to the inner insert pipe through the built-in telescopic pipe, and a sliding combined seal is used to ensure reliable sealing during the threading process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings: Figure 1 Shows a schematic structural diagram of a screen inner insert pipe completion string of an embodiment of the present invention; Figure 2 Shows a schematic diagram of a packer-type liner hanger of an embodiment of the present invention; Figure 3The figure shows a schematic diagram of a retrievable ball seat device according to an embodiment of the present invention, showing a schematic installation diagram; Figure 4 is Figure 3 An enlarged view of part A in the figure shows the structure of the retrievable ball seat device; Figure 5 The figure shows a schematic diagram of a hydraulic release running tool according to an embodiment of the present invention; Figure 6 The figure shows a schematic diagram of a baffle according to an embodiment of the present invention; Figure 7 The figure shows a schematic diagram of a tubing plug and an insertion seat according to an embodiment of the present invention; The drawings are not necessarily drawn to actual scale.

[0029] The meanings of the reference numerals in the drawings are as follows: 100, drill string; 200, packer type liner hanger; 300, hydraulic release running tool; 400, retrievable ball seat device; 500, matching long and short casing pipes; 600, inner string; 700, screen pipe; 800, tubing plug and insertion seat; 900, guide shoe; 201, tie-back barrel; 202, packer unit; 203, hanger unit; 301, lifting nipple; 302, jaw mechanism; 303, ratchet mechanism; 304, pressure holding ball; 401, housing; 402, ball seat; 403, tubing nipple; 404, compression cap; 405, side hole; 406, shear pin; 407, universal joint; 408, upper joint of ball seat; 409, baffle; 410, lower joint of ball seat; 411, built-in telescopic pipe; 412, sealing assembly; 413, sliding combined seal; 414, flow-through hole; 415, double male coupling; 801, insertion head; 802, insertion seat; 803, sealing surface of insertion seat; 804, sealing ring. Detailed implementation manners

[0030] In order to make the technical solutions and advantages of the present invention clearer, the following further describes the exemplary embodiments of the present invention in detail with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. And without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0031] Horizontal well screen completion is widely promoted and applied in oil fields because of its simple completion technology, small pollution to the reservoir, and low completion cost. However, during the drilling process, the filter cake easily formed on the wellbore wall by drilling mud can ensure the stability of the wellbore, but also cause pollution to the oil layer.

[0032] At present, during well completion in China, the main method for well flushing and acid washing to remove blockages in horizontal wells is to connect the well flushing valve to the bottom of the screen pipe and lower them together to the designed depth, and use an external packer in the screen pipe section for segmented treatment. After well completion, an acid washing pipe string composed of an inner insert pipe, an acid washing packer, a liquid discharge valve, etc. needs to be lowered into the screen pipe. Cooperating with the external packer, the horizontal section is divided into several sections, and the inner insert pipe is inserted into the well flushing valve on the screen pipe to form a well flushing channel. First, pressure is applied to set the packer, and then in a reverse circulation mode, under the action of the packer, the acid solution flows between the screen pipe and the formation, so as to achieve the purpose of acid washing the open hole wellbore.

[0033] However, the construction process in the existing technology is complex, and there are problems such as incomplete circulation between the screen pipe and the open hole section and wellbore pollution.

[0034] To solve the above problems, the present invention proposes a retrievable liner hanger device, which uses a single pipe string to establish a screen pipe circulation acid washing channel. The liner hanger and the retrievable inner insert pipe structure are integrally designed. The upper part is connected by a drill string, and the lower part connects the completion screen pipe and the inner insert pipe, which can simplify the acid washing operation process of screen pipe well completion, effectively solve the problems of incomplete circulation between the screen pipe and the open hole section and wellbore pollution, improve the well completion transformation efficiency, and have good economic benefits.

[0035] In the embodiment as Figure 1 shown, a retrievable liner hanger device includes: A packer-type liner hanger 200, which is set and sealed under the drive of hydraulic pressure; A retrievable ball seat device 400, in which a ball seat is arranged, and the ball seat is connected to the drill string 100 through a hydraulic release running tool 300; Among them, after the pressure build-up ball 304 is put in, it falls into the ball seat of the retrievable ball seat device 400 to build up pressure in the pipe. When the pressure reaches the first set value, the packer-type liner hanger 200 is set; when the pressure reaches the second set value, the hydraulic release running tool is separated from the ball seat to complete the release; when the pressure reaches the third set value, the ball seat falls off and the circulation in the pipe is re-established. After the acid washing is completed, first lift the pipe string, then lower the pressure to set the packer, and then continue to lift the pipe string, and the running tool and the inner insert pipe can be recovered completely.

[0036] In the retrievable liner hanger according to this embodiment, the hydraulic release running tool 300 can be run into the wellbore and released hydraulically. Through the retrievable liner hanger described in this embodiment, the liner hanger and the retrievable inner string 600 are integrally designed, enabling a single trip string to establish a circulation and pickling channel for the screen pipe 700, simplifying the pickling operation process for screen pipe 700 completion, effectively solving the problems of incomplete circulation between the screen pipe 700 and the open hole section and wellbore contamination, and improving the completion stimulation efficiency.

[0037] In one embodiment, as Figure 2 shown, the packer-type liner hanger 200 includes a packer unit 202 and a hanger unit 203. A setting block is provided on the packer unit 202. After pickling is completed, the pipe string is first lifted and then the packer is pressed down to achieve mechanical setting, and the hanger unit 203 is set under the action of internal pressure.

[0038] In one embodiment, as Figure 3 and 4 shown, the retrievable ball seat includes a housing 401. The upper end of the housing 401 is connected to the packer-type liner hanger 200, and the lower end is connected to the screen pipe 700. A ball seat joint assembly is provided inside the housing 401. The upper end of the ball seat joint assembly is connected to the ball seat through a shear pin 406, and the shear pressure of the shear pin 406 is a third set value. The lower end of the ball seat joint assembly is connected to the inner string 600.

[0039] In the retrievable liner hanger according to this embodiment, the housing 401 and its internal components are respectively connected to the screen pipe 700 and the inner string 600 of the lower pipe string. In this embodiment, the outer side of the ball seat joint assembly is hermetically connected to the inner side of the housing 401, ensuring that after the pressure holding ball 304 falls into the ball seat, the pressure holding process will not affect the lower part of the ball seat, thereby ensuring the smooth setting of the packer-type liner hanger 200 above the ball seat and the smooth separation of the hydraulic release running tool.

[0040] In one embodiment, as Figure 4 shown, a tubing nipple 403 is connected above the ball seat, and the tubing nipple 403 is connected to the hydraulic release running tool through a double male coupling 415.

[0041] In this embodiment, a number of side holes 405 are provided on the tubing nipple 403 for pressure transmission. After the pressure holding ball 304 falls into the ball seat, the pressure inside the pipe can be transmitted to the outside of the drill string 100 and the inside of the housing 401 through the side holes 405, so as to act on the packer-type liner hanger 200 above, and then drive the packer-type liner hanger 200 to set.

[0042] In one embodiment, asFigure 4 As shown, the ball socket joint assembly includes an upper ball socket joint 408 and a lower ball socket joint 410. A baffle 409 is fixedly arranged between the upper ball socket joint 408 and the lower ball socket joint 410. A plurality of fluid passing holes 414 are arranged on the baffle 409 for fluid (such as Figure 6 shown) to flow through. The diameter of each fluid passing hole 414 is smaller than the diameter of the pressure holding ball 304 to prevent the pressure holding ball 304 from flowing out through the fluid passing holes 414.

[0043] When the ball socket drops off when the pressure in the pipe reaches the third set value, the ball socket will move downward to the position of the baffle 409. Since the outer diameter of the ball socket is smaller than the diameter of the baffle 409, the ball socket will not block the entire baffle 409, and not all of the fluid passing holes 414 on the baffle 409 will be blocked. The fluid will flow through the fluid passing holes 414 to establish a circulation.

[0044] The upper ball socket joint 408 includes a cylindrical upper joint body. The upper end of the joint body is provided with an inwardly contracting interface. The ball socket is installed on the interface and fixed by a shear pin 406. A sealing assembly 412 is arranged between the outer wall of the upper joint body and the inner wall of the housing 401 to ensure static sealing during the hanging of the hanger, hydraulic release of the hand, and pressure holding of the ball socket, and to prevent the communication between the liner and the lower pipe string and the annulus.

[0045] The lower end of the upper ball socket joint 408 is connected to the upper end of the lower ball socket joint 410 by a thread.

[0046] The lower ball socket joint 410 includes a cylindrical lower joint body. The lower end of the lower joint body is provided with a connection assembly for connecting the inner insert pipe 600.

[0047] In one embodiment, as Figure 4 shown, a compression cap 404 is further arranged on the upper ball socket joint 408. The compression cap 404 has a cylindrical structure. The upper end of it is provided with an inwardly contracting opening and is sleeved on the lower part of the tubing nipple 403. The lower end of the compression cap 404 is arranged outside the interface at the upper end of the upper ball socket joint 408.

[0048] By arranging the compression cap 404, support can be provided for the tubing nipple 403 to prevent it from being deflected or oscillated during rotation.

[0049] The lower end of the tubing nipple 403 is also connected to the upper ball socket joint 408 through a universal shaft 407 to ensure rotational connection between the tubing nipple 403 and the upper ball socket joint 408.

[0050] In one embodiment, a matching length sleeve 500 is arranged between the packer type liner hanger 200 and the housing 401 of the retrievable ball socket device 400.

[0051] The length of the matching long and short sleeves 500 can be selected, and multiple matching long and short sleeves 500 can be set. Each pair of matching long and short sleeves 500 is connected by a double male joint.

[0052] By setting the matching long and short sleeves 500, it can be selected according to the distance between the packer liner hanger 200 and the retrievable ball seat device 400, ensuring that different distance lengths can be adapted.

[0053] In one embodiment, a built-in telescopic tube 411 is provided at the lower part of the ball seat lower sub 410, and the built-in telescopic tube 411 can be connected to the inner insert tube 600. A sliding combined seal 413 is provided on the built-in telescopic tube 411.

[0054] In this embodiment, the built-in telescopic tube 411 is allowed to move inside the ball seat lower sub 410, ensuring that when the hydraulic release running tool 300 is threadedly connected to the inner insert tube 600, there is still a space for the packer liner hanger 200 body to continue to move down for threading. When the built-in telescopic tube 411 abuts against the baffle 409, the drill string 100 and the liner hanger can be appropriately pressed down to ensure that the thread connection between the built-in telescopic tube 411 at the lower end of the retrievable ball seat device 400 and the inner insert tube 600 is tightened. At the same time, during the well flushing (acid pickling) operation, the built-in telescopic tube 411 is allowed to move up and down inside the ball seat lower sub 410 to avoid seal failure caused by pipe string movement due to factors such as pump pressure and displacement changes, thus affecting the well flushing (acid pickling) effect.

[0055] In one embodiment, as Figure 5 shown, a lifting short section 301 is provided at the upper end of the hydraulic release running tool 300. The lifting short section 301 is connected to the drill string 100 by drill pipe threads. A jaw mechanism 302 is also provided on the hydraulic release running tool, and the jaw mechanism 302 can achieve the effect of rotating and running the hydraulic release running tool 300 into the packer liner hanger 200.

[0056] The packer liner hanger 200 is connected to the hydraulic release running tool 300 through a ratchet mechanism 303 inside.

[0057] The traditional screen pipe 700 completion string requires a pickling string composed of an inner insert pipe 600, a pickling packer, a drain valve, etc. to be run into the screen pipe 700. In cooperation with an external packer, first insert the inner insert pipe 600 into the washing valve on the screen pipe 700 to form a washing channel. First, apply pressure to set the packer, and then use the reverse circulation method to make the acid solution flow between the screen pipe 700 and the formation under the action of the packer, so as to realize pickling the open-hole wellbore; the entire pipe string structure is complex, positive circulation large-displacement well washing cannot be carried out, and the circulation between the screen pipe 700 and the formation is not thorough; the use of an external packer also increases the risk of running the pipe string, and the construction cost is relatively high. Therefore, the present invention integrates the tail pipe hanger and the retrievable inner insert pipe 600 structure through the screen pipe inner insert pipe completion string and the retrievable suspension device, realizes the establishment of a screen pipe 700 circulation pickling channel with one trip of the pipe string, simplifies the screen pipe 700 completion pickling operation process, effectively solves the problems of incomplete circulation between the screen pipe 700 and the open-hole section and wellbore pollution, and improves the completion reconstruction efficiency.

[0058] According to another aspect of the present invention, a screen pipe inner insert pipe completion string is also proposed, including: A tail pipe hanger device; A screen pipe 700 and an inner insert pipe 600 arranged at the lower end of the tail pipe hanger device, and the inner insert pipe 600 is sleeved inside the screen pipe 700; A guide shoe 900 is arranged below the inner insert pipe 600; Wherein, the tail pipe hanger device is the retrievable tail pipe hanger device described above.

[0059] As Figure 7 shown, an insertion head 801 is arranged at the lower end of the inner insert pipe 600, and the insertion head 801 is in plug-in fit with an insertion seat 802, and the insertion seat 802 is connected to the guide shoe 900.

[0060] The following will be described in conjunction with specific embodiments.

[0061] Embodiment 1 A retrievable tail pipe hanger device includes a drill string 100, and a hydraulic release running tool 300 is connected to the lower end of the drill string 100. It passes through the packoff tail pipe hanger 200 and extends below the packoff tail pipe hanger 200, and is connected to the retrievable ball seat device 400.

[0062] Inside the packoff tail pipe hanger 200, it is connected to the hydraulic release running tool 300 through a ratchet mechanism 303.

[0063] The lower end of the hydraulic release running tool 300 is connected to the ball seat of the retrievable ball seat device 400 through a double-male coupling 415. Among them, the double-male coupling 415 is connected to the ball seat through a tubing nipple 403.

[0064] The packer type liner hanger 200 is connected to the housing 401 of the retrievable ball seat device 400 through the matching long and short casing pipes 500.

[0065] There is a sealing assembly 412 between the retrievable ball seat device 400 and the packer type liner hanger 200, which is used to ensure the static seal during the setting of the hanger, hydraulic release of the string, and ball seat plugging, and avoid the communication between the liner and the lower pipe string and annulus.

[0066] An internal telescopic pipe 411 is provided inside the ball seat sub - joint 410; there is a sliding combined seal 413 between the retrievable ball seat device 400 and the internal telescopic pipe 411, which is used to ensure reliable sealing during the make - up connection process between the hanger and the inner inserted pipe 600.

[0067] The packer type liner hanger 200 includes a tie - back cylinder 201, a packer unit 202, and a hanger unit 203. Among them, the tie - back cylinder 201 is connected to the packer unit 202 through taper threads, and the packer unit 202 is connected to the hanger unit 203 through casing threads.

[0068] When the pipe string is lowered to the designed position, a pressure - building ball 304 is dropped into the interior of the wellhead drill string 100. After the ball falls into the ball seat position, pressure is built up inside the drill string 100 above the retrievable ball seat device 400. The pressure is transmitted through the side hole 405 on the tubing nipple 403 to the annulus above the packer type liner hanger 200, the hydraulic release running tool 300, and the retrievable ball seat device 400. Building up a pressure of 10 MPa realizes the setting of the liner hanger. Continuing to build up pressure to 14 MPa for hydraulic release of the running tool; then continuing to build up pressure to 20 MPa, the shear pin 406 on the ball seat is sheared, and the ball seat moves down to the baffle 409 to re - establish circulation.

[0069] Embodiment 2 A retrievable liner hanging device, with the following additional structure for running in on the basis of Embodiment 1: The lower end of the tubing nipple 403 on the retrievable ball seat device 400 is rotationally connected to the pressure cap 404 and the ball seat upper sub - joint 408 by means of a universal shaft 407.

[0070] The upper end of the tubing nipple 403 is connected to the hydraulic release running tool 300 through a double - female coupling 415; when the packer type liner hanger 200 is made up with the screen pipe 700, after the hydraulic release running tool 300 is connected to the tubing nipple 403, it can rotate through the universal shaft 407. The ball seat upper sub - joint 408 is threadedly connected to the ball seat lower sub - joint 410 and is provided with a sealing ring, which can realize pressure building inside the ball seat lower sub - joint 410. The baffle 409 is arranged between the ball seat upper sub - joint 408 and the ball seat lower sub - joint 410, which can prevent the ball seat and the pressure - building ball 304 from falling into the well after the ball seat is plugged through.

[0071] The built-in telescopic pipe 411 allows for movement inside the lower joint 410 of the ball seat, ensuring that when the hydraulic release running tool 300 is screwed onto the inner liner 600 (oil pipe), there is space for the body of the packer tailpipe hanger 200 to continue descending and engaging the threads. When the built-in telescopic pipe 411 abuts against the baffle 409, the drill string 100 and the tailpipe hanger can be appropriately pressed down to ensure that the threaded connection between the built-in telescopic pipe 411 at the lower end of the retrievable ball seat device 400 and the inner liner 600 (oil pipe) is tightened. At the same time, during the well flushing (acid pickling) operation, the built-in telescopic pipe 411 is allowed to move up and down inside the lower joint 410 of the ball seat, avoiding seal failure caused by pipe string movement due to factors such as pump pressure and displacement changes, which could otherwise affect the well flushing (acid pickling) effect.

[0072] Embodiment 3 A completion string for a screen inner liner includes a drill string 100, a packer tailpipe hanger 200, a hydraulic release running tool 300, a retrievable ball seat device 400, a matching long and short casing 500, an inner liner 600 (oil pipe), a screen 700, a tubing insert head 801 and an insert seat 802, a guide shoe 900, etc., which are connected in sequence.

[0073] The drill string 100 is connected to the packer tailpipe hanger 200 through the hydraulic release running tool 300; the lower end of the hydraulic release running tool 300 is connected to the retrievable ball seat device 400 by tubing threads; the lower end of the packer tailpipe hanger 200 is connected to the housing 401 of the retrievable ball seat device 400 by casing threads through the matching long and short casing 500.

[0074] The housing 401 of the retrievable ball seat device 400 is connected to the screen 700 by casing threads; the inside of the ball seat device is connected to the inner liner 600 (oil pipe) by tubing threads; the inner liner 600 (oil pipe) is connected to the tubing insert head 801 and the insert seat 802 by tubing threads; the tubing insert head 801 and the insert seat 802 are connected to the guide shoe 900 by casing threads.

[0075] The lifting sub 301 at the upper end of the hydraulic release running tool 300 is connected to the drill string 100 by drill pipe threads; the tool can be rotated and run in through the jaw mechanism 302 inside the packer tailpipe hanger 200; the inside of the packer tailpipe hanger 200 is connected to the hydraulic release running tool 300 through the ratchet mechanism 303.

[0076] The present invention establishes a circulation acid pickling channel for the screen 700 with a single trip string.

[0077] The tailpipe hanger and the retrievable inner liner 600 are designed with an integrated structure, and the tailpipe hanger, the retrievable ball seat unit and the inner liner 600 are connected by a central pipe.

[0078] The present invention adopts the mature packer-type liner hanger technology, and the performance of setting, setting packer and releasing is reliable.

[0079] The present invention adopts forward circulation well flushing (pickling) to ensure thorough circulation between the screen pipe 700 and the open hole section. After the pipe string is lowered in place, first drop the pressure-holding ball 304 to verify setting, releasing and open the ball seat by pressure, then carry out forward pickling operation, and finally set the packer to meet the requirements of reservoir stimulation.

[0080] After pickling in the present invention, first lift the pipe string, then press down to set the packer, and then continue to lift the pipe string, then the running tool and the inner string 600 can be recovered completely. The operation is simple and the construction risk is reduced. The retrievable ball seat and the inner string 600 are connected by an internal telescopic pipe, and a sliding combined seal 413 is adopted to ensure reliable sealing during the threading process.

[0081] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and do not imply limitation.

[0082] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0083] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0084] Certain terms are used throughout this application to refer to particular system components. As those skilled in the art will recognize, the same components may typically be referred to by different names, and thus this application is not intended to distinguish between components that differ only in name and not in function. The phrase "an embodiment" or "embodiments" as used in the specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the phrase "an embodiment" or "embodiments" that appears throughout the specification is not necessarily all referring to the same embodiment.

[0085] The embodiments of the present invention are given for purposes of illustration and description, and are not exhaustive or limit the invention to the disclosed forms. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described in order to better explain the principles of the invention and its practical application, and to enable those of ordinary skill in the art to understand the invention so as to design various embodiments with various modifications suitable for a particular purpose.

[0086] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made by those skilled in the art once they learn of the basic inventive concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and / or modifications that fall within the scope of the present invention. All changes and / or modifications made in accordance with the embodiments of the present invention should be covered within the protection scope of the present invention.

Claims

1. A retrievable liner hanger, characterized in that, Comprising: A packer-type liner hanger (200) that is set and sealed under hydraulic drive; A retrievable ball seat device (400) with a ball seat disposed therein, and the upper end of the ball seat is connected to a drill string (100) through a hydraulic release running tool (300); Wherein, when a pressure ball (304) falls into the ball seat, the pressure inside the pipe increases. When the pressure reaches a first set value, the packer-type liner hanger (200) is set; when the pressure reaches a second set value, the hydraulic release running tool is separated from the ball seat to complete the release; when the pressure reaches a third set value, the ball seat falls off and circulation is re-established inside the pipe; after pickling is completed, first lift the pipe string, then press down to set the packer, and then continue to lift the pipe string to recover all the running tool and the inner liner.

2. The retrievable liner hanger device according to claim 1, wherein, The retrievable ball seat includes a housing (401), the upper end of the housing (401) is connected to the packer-type liner hanger (200), and the lower end is connected to a screen pipe (700); A ball seat joint assembly is disposed inside the housing (401). The upper end of the ball seat joint assembly is connected to the ball seat through a shear pin (406), and the lower end of the ball seat joint assembly is connected to an inner liner (600).

3. The retrievable liner hanger device according to claim 2, wherein, A tubing nipple (403) is connected above the ball seat, and the tubing nipple (403) is connected to the hydraulic release running tool through a double-male coupling (415); Wherein, a number of side holes (405) for transmitting pressure are provided on the tubing nipple (403).

4. The retrievable liner hanger device according to claim 3, characterized in that, The ball seat joint assembly includes a ball seat upper sub (408) and a ball seat lower sub (410). A baffle (409) is fixedly disposed between the ball seat upper sub (408) and the ball seat lower sub (410), and a number of flow holes (414) for fluid flow are provided on the baffle (409).

5. The retrievable liner hanger device according to claim 4, wherein, A compression cap (404) is further provided on the ball seat upper sub (408). The compression cap (404) is sleeved on the lower part of the tubing nipple (403), and the lower end of the tubing nipple (403) is also connected to the ball seat upper sub (408) through a universal joint (407).

6. The retrievable liner hanger device according to claim 5, wherein A matching long and short casing (500) is provided between the packer-type liner hanger (200) and the housing (401) of the retrievable ball seat device (400).

7. The retrievable liner hanger device according to claim 6, wherein, An internal telescopic pipe (411) is provided below the ball seat lower sub (410). The internal telescopic pipe (411) can telescopically move inside the lower sub, and the lower end of the internal telescopic pipe (411) is connected to the inner liner (600).

8. The retrievable liner hanger device according to claim 7, wherein, The upper end of the hydraulic release running tool (300) is provided with a lifting nipple (301) connected to the drill string (100); a dog clutch mechanism (302) cooperating with the inner wall of the packer-type liner hanger (200) is also provided on the hydraulic release running tool (300); The hydraulic release running tool is connected to the packer-type liner hanger (200) through a ratchet mechanism (303).

9. A completion string for an inner pipe inserted into a screen pipe, characterized in that, Comprising: A liner hanging device; A screen pipe (700) and an inner liner (600) disposed at the lower end of the liner hanger device, the inner liner (600) being sleeved inside the screen pipe (700); A guide shoe (900) is disposed below the inner liner (600); Wherein, the liner hanger device is a retrievable liner hanger device according to any one of claims 1 to 8.

10. The screen pipe inner string completion string according to claim 1, characterized in that, An insertion head (801) is disposed at the lower end of the inner liner (600), the insertion head (801) being in plug-in fit with an insertion seat (802), and the insertion seat (802) is connected to the guide shoe (900).

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