阅读说明：本技术 一种碳酸盐岩油井筛管完井管柱及解卡方法 (Completion pipe string of carbonate rock oil well screen pipe and unfreezing method ) 是由 张保贵 柏轲 于 2019-11-28 设计创作，主要内容包括：本发明公开了一种碳酸盐岩油井筛管完井管柱及解卡方法,包括自上而下连接的可旋转丢手器、安全接头、暂堵筛管和冲洗头；可旋转丢手器包括芯轴、缸套、活塞、外筒体、开口棘齿卡圈、上锥体、下锥体、膨胀套、卡块、凡尔座、下接头、下封头；缸套、活塞、下锥体、下接头从上至下依次嵌套在芯轴外侧；活塞与芯轴固定连接；下接头与下锥体的下端固定连接；外筒体、开口棘齿卡圈、上锥体、膨胀套均嵌套在下锥体外侧；芯轴中下部本体上开设多个孔眼,孔眼的位置和大小与下锥体凹槽相对应；卡块位于下锥体的凹槽和芯轴的孔眼中,下封头固定连接在芯轴下端。本发明所提供的装置和方法能有效处理现有技术难以处理的严重遇阻、遇卡、不能一次下到位的问题。(The invention discloses a completion pipe string of a carbonatite oil well screen pipe and a stuck releasing method, wherein the completion pipe string comprises a rotatable releasing device, a safety joint, a temporary plugging screen pipe and a flushing head which are connected from top to bottom; the rotatable releasing device comprises a mandrel, a cylinder sleeve, a piston, an outer cylinder body, an opening ratchet collar, an upper cone, a lower cone, an expansion sleeve, a clamping block, a valve seat, a lower joint and a lower sealing head; the cylinder sleeve, the piston, the lower cone and the lower joint are sequentially nested outside the mandrel from top to bottom; the piston is fixedly connected with the mandrel; the lower joint is fixedly connected with the lower end of the lower cone; the outer cylinder body, the opening ratchet retainer ring, the upper cone body and the expansion sleeve are all nested outside the lower cone body; a plurality of holes are formed in the body of the middle lower part of the mandrel, and the positions and the sizes of the holes correspond to those of the lower cone groove; the fixture block is positioned in the groove of the lower cone and the hole of the mandrel, and the lower end enclosure is fixedly connected to the lower end of the mandrel. The device and the method provided by the invention can effectively solve the problems that the prior art is difficult to process and can not be put in place at one time when being seriously blocked and blocked.)

1. A completion pipe string of a carbonate oil well sieve pipe comprises a rotatable releasing device, a safety joint, a temporary plugging sieve pipe and a flushing head which are connected from top to bottom;

the rotary releasing device is characterized by comprising a mandrel, a cylinder sleeve, a piston, an outer cylinder body, an opening ratchet retainer ring, an upper cone, a lower cone, an expansion sleeve, a clamping block, a valve seat, a lower joint and a lower end enclosure; the cylinder sleeve, the piston, the lower cone and the lower joint are sequentially nested outside the mandrel from top to bottom; the piston, the cylinder sleeve and the mandrel are sealed, so that a sealed hollow cavity is formed inside the mandrel; the piston is fixedly connected with the mandrel through a shearable pin; the lower joint is fixedly connected with the lower end of the lower cone; the outer cylinder body, the opening ratchet collar, the upper cone body and the expansion sleeve are all nested outside the lower cone body; the outer wall of the middle part of the lower cone is provided with a pawl structure, and the inner part of the middle lower part of the lower cone is provided with a plurality of discontinuous grooves; a plurality of holes are formed in the body of the middle lower part of the mandrel, and the positions and the sizes of the holes correspond to those of the lower cone groove; the fixture block is positioned in the groove of the lower cone and the hole of the mandrel, and the lower end socket is fixedly connected to the lower end of the mandrel;

the temporary plugging sieve tube comprises a base tube, wherein the base tube adopts a circular tubular column, a plurality of holes are uniformly drilled in the tubular column, and temporary plugging sheets are arranged in the holes;

the safety joint, the flushing head and the temporary plugging sieve tube are all made of materials easy to drill and grind.

2. The carbonate well screen completion string as defined in claim 1, wherein the valve seat is fixed inside the mandrel by a shearable pin, and the fixture block is pressed into the groove of the lower cone, thereby realizing the connection of the fixture block to the groove of the lower cone and the hole of the mandrel.

3. A carbonate well screen completion string according to claim 2, wherein the inner diameter of the lower head is smaller than the outer diameter of the valve seat.

4. The carbonate well screen completion string of claim 1 or 3, wherein the temporary plugging screen comprises a base pipe, a collar, a temporary plugging sheet, a seal ring and a pressure ring.

5. A carbonate well screen completion string according to claim 4, wherein the perforations of the temporary plugging screen comprise two portions of different diameters, being a first and a second perforation respectively; the first hole is positioned on the inner side of the pipe body, the second hole is positioned on the outer side of the pipe body, and the diameter of the second hole is larger than that of the first hole; the step has between first punchhole and the second punchhole for support temporary plugging sheet, and be equipped with the recess on the step, the sealing washer is located the recess of step, then places temporary plugging sheet in the second punchhole, the clamping ring is fixed on second punchhole upper portion, will temporarily plug the sheet top and press on the step.

6. The carbonate well screen completion string of claim 5, wherein in the temporary plugging screen, the temporary plugging sheet is made of a polymer material soluble in formation fluid;

in the temporary plugging sieve tube, the base tube and the pressure ring are made of aluminum alloy materials easy to drill and grind.

7. The stuck freeing method of carbonate well screen completion string as claimed in claim 5, comprising the steps of:

s100, respectively assembling and forming the rotatable releasing device and the temporary plugging sieve tube to meet the requirements of connection and sealing standards;

s200, connecting the rotatable release device, the safety joint, the temporary plugging screen pipe and the flushing head from top to bottom to form a screen pipe well completion pipe string, connecting the screen pipe well completion pipe string to the bottom of the upper pipe string by using a drill pipe or an oil pipe as the upper pipe string, and putting the screen pipe well completion pipe string into the bottom of the well by using the upper pipe string;

s300, in the descending process, once blockage and blockage are encountered, blockage removal operation is carried out, the blockage removal operation comprises the steps of adopting large-displacement forward circulation or reverse circulation flushing of blockage removal liquid, wherein the blockage removal liquid can circulate to the bottom of the well and is sprayed out or enters through a flushing head because the sieve tube hole is in a temporary blockage state, and effective flushing of the blockage and blockage encountering points by flushing liquid is guaranteed; simultaneously, the wellhead rotates the upper pipe column to drive the lower pipe column to rotate, the lower pipe column rotates while washing, and the lower pipe column is slowly lifted up until the completion pipe column is unfreezed;

s400, after the screen pipe completion pipe string is successfully put into the well bottom, circularly washing the well, and removing well wall mud and well bore impurities;

s500, after well flushing is completed, releasing is completed, an upper pipe column is lifted out, and open flow and liquid drainage are performed; the temporary plugging pieces of the temporary plugging screen pipe left under the well are dissolved, and the screen pipe recovers the flowing capacity and the supporting function.

S600, in the later-stage well repairing process, a special fishing tool is put in to fish out the rotatable releasing device, then a drilling and grinding tool is put in to directly drill and grind part of elements, the safety joint, the temporary plugging sieve tube and the flushing head of the rotatable releasing device left in the well, the shaft is restored again, and secondary well completion is carried out.

8. The method of claim 7, wherein the plugging solution is selected from the group consisting of completion fluid, acid, mud cake solution, and lubricant from a virgin well.

9. The stuck release method of the carbonate well screen completion string as claimed in claim 7, wherein the releasing step in step S500 is as follows:

firstly, throwing a ball into the rotatable releasing device, pressing the ball after the ball falls into the valve seat, shearing a pin at the upper part of the piston by pressure, driving the outer sleeve and the upper cone to move downwards by the downward movement of the piston, expanding two ends of the slot expansion sleeve under the extrusion action of the upper cone and the lower cone, and enabling the slot expansion sleeve to be tightly attached to the inner wall of the sleeve, thereby achieving the effect of hanging and supporting a lower tubular column; after the upper cone body descends, the opening ratchet retainer ring is clamped on the inverted teeth in the middle of the lower cone body, so that the sleeve can be prevented from loosening during hanging;

then, continuously pressurizing, wherein as the pin pressure bearing of the valve seat is larger than the pin pressure bearing of the piston, when the pressure is further increased, the pin of the valve seat is sheared off, and the sliding down of the valve seat is caught by the lower end enclosure; lifting the upper pipe column, enabling the fixture block and the ball to fall into the valve seat, separating the mandrel from the lower cone, lifting the mandrel together with the valve seat, the cylinder sleeve and the outer sleeve, and clamping the lower cone in the outer sleeve to realize releasing and separating of the upper pipe column.

10. The method of claim 9, wherein the releasing step of step S500 is performed to block the upper pressure hole of the mandrel, press the ball, and leave the upper portion unsupported, so that only the lower valve pin is sheared, and support the tubular string at the bottom of the well, if no upper suspension support is required.

Technical Field

The invention relates to the technical field of well completion engineering, in particular to a completion pipe string of a carbonate oil well screen pipe and a stuck releasing method.

Background

Of the oil and gas reserves that have been explored globally, 60% are marine carbonate reservoirs. Carbonate reservoirs in China are also widely distributed, mainly distributed in Tarim basins and Sichuan basins, and have huge exploration and development potentials. Currently, carbonate reservoirs are generally completed in an open hole manner. Due to the change of the stratum stress and the rock strength, the borehole wall instability is easy to occur in the open hole well completion, the borehole wall collapses, the reservoir is buried by sand, and the normal production of the oil well is influenced. In order to support the open hole well wall and prevent the well wall from collapsing and sand burying, the prior art adopts a sieve tube to complete the well. However, the existing screen pipe well completion pipe string is not easy to salvage out under the condition of sand burying, the well repairing difficulty is high, and the later-stage operations of sidetracking, layer changing, deepening and the like are affected. In order to solve the problem, in the prior art, an easily drilled and ground sieve tube is adopted to complete the well in the carbonate oil well, sieve tube fishing is not needed in the later stage, the easily drilled and ground sieve tube can be directly drilled and ground, and then the well is completed again, and the Chinese patent CN107939358A introduces the well completion condition of the easily drilled and ground sieve tube. At present, the technology is already popularized and applied to Haraha pond oil fields and Tahe oil fields of Tarim basins. However, in the process of screen pipe well completion, the problems of blockage and blockage occur and the pipe string cannot be put in place, and particularly in a high-inclination horizontal well, the problems are easy to occur. Aiming at the problems, the blockage is usually released by adopting a large-discharge flushing and movable pipe column mode at present, but due to the special structures of the sieve pipe and the releasing device, blockage releasing liquid passes through the sieve pipe hole and cannot flush the position which meets the blockage and the blockage; meanwhile, the existing releasing device cannot drive the lower well completion pipe string to rotate. Therefore, once the problems of blockage and blockage of the screen pipe completion occur, the effective blockage removal treatment is difficult to perform, and complicated accidents can be caused.

Disclosure of Invention

Aiming at the problems, the invention provides a completion pipe string of a carbonate oil well screen pipe and a stuck releasing method. The novel steel wire rope clamp is simple in structure and convenient to mount and dismount, and can effectively solve the problem that the prior art is difficult to handle, and the problem that the steel wire rope clamp is blocked and cannot be put in place at one time can be solved.

The technical scheme of the invention is as follows:

a completion pipe string of a carbonate oil well sieve pipe comprises a rotatable releasing device, a safety joint, a temporary plugging sieve pipe and a flushing head which are connected from top to bottom;

the rotatable releasing device comprises a mandrel, a cylinder sleeve, a piston, an outer cylinder body, an opening ratchet collar, an upper cone, a lower cone, an expansion sleeve, a clamping block, a valve seat, a lower joint and a lower sealing head; the cylinder sleeve, the piston, the lower cone and the lower joint are sequentially nested outside the mandrel from top to bottom; the piston, the cylinder sleeve and the mandrel are sealed, so that a sealed hollow cavity is formed inside the mandrel; the piston is fixedly connected with the mandrel through a shearable pin; the lower joint is fixedly connected with the lower end of the lower cone; the outer cylinder body, the opening ratchet collar, the upper cone body and the expansion sleeve are all nested outside the lower cone body; the outer wall of the middle part of the lower cone is provided with a pawl structure, and the inner part of the middle lower part of the lower cone is provided with a plurality of discontinuous grooves; a plurality of holes are formed in the body of the middle lower part of the mandrel, and the positions and the sizes of the holes correspond to those of the lower cone groove; the fixture block is positioned in the groove of the lower cone and the hole of the mandrel, and the lower end socket is fixedly connected to the lower end of the mandrel;

the temporary plugging sieve tube comprises a base tube, wherein the base tube adopts a circular tubular column, a plurality of holes are uniformly drilled in the tubular column, and temporary plugging sheets are arranged in the holes;

the safety joint, the flushing head and the temporary plugging sieve tube are all made of materials easy to drill and grind.

Furthermore, the valve seat is fixed inside the mandrel through a pin capable of being sheared, the fixture block is pressed into the groove of the lower cone, and the connection of the fixture block to the groove of the lower cone and the hole of the mandrel is realized.

Further, the inner diameter of the lower end socket is smaller than the outer diameter of the valve seat.

Furthermore, the temporary plugging sieve tube comprises a base tube, a coupling, a temporary plugging sheet, a sealing ring and a pressure ring.

Further, the holes of the temporary plugging sieve tube comprise two parts with different diameters, namely a first hole and a second hole. The first hole is positioned on the inner side of the pipe body, the second hole is positioned on the outer side of the pipe body, and the diameter of the second hole is larger than that of the first hole; the step has between first punchhole and the second punchhole for support temporary plugging sheet, and be equipped with the recess on the step, the sealing washer is located the recess of step, then places temporary plugging sheet in the second punchhole, the clamping ring is fixed on second punchhole upper portion, will temporarily plug the sheet top and press on the step.

Furthermore, in the temporary plugging sieve tube, the temporary plugging sheet is processed by adopting a polymer material which is soluble in formation fluid.

Further, the temporary plugging sheet is made of polyester BA1-28, and the compression strength is required to be more than 5 MPa;

furthermore, in the temporary plugging sieve tube, the base tube and the pressure ring are made of aluminum alloy materials which are easy to drill and grind.

A stuck releasing method for a completion pipe string of a carbonate oil well sieve pipe comprises the following steps:

s100, respectively assembling and forming the rotatable releasing device and the temporary plugging sieve tube to meet the requirements of connection and sealing standards;

s200, connecting the rotatable release device, the safety joint, the temporary plugging screen pipe and the flushing head from top to bottom to form a screen pipe well completion pipe string, connecting the screen pipe well completion pipe string to the bottom of the upper pipe string by using a drill pipe or an oil pipe as the upper pipe string, and putting the screen pipe well completion pipe string into the bottom of the well by using the upper pipe string;

s300, in the descending process, once blockage and blockage are encountered, blockage removal operation is carried out, the blockage removal operation comprises the steps of adopting large-displacement forward circulation or reverse circulation flushing of blockage removal liquid, wherein the blockage removal liquid can circulate to the bottom of the well and is sprayed out or enters through a flushing head because the sieve tube hole is in a temporary blockage state, and effective flushing of the blockage and blockage encountering points by flushing liquid is guaranteed; simultaneously, the wellhead rotates the upper pipe column to drive the lower pipe column to rotate, the lower pipe column rotates while washing, and the lower pipe column is slowly lifted up until the completion pipe column is unfreezed;

s400, after the screen pipe completion pipe string is successfully put into the well bottom, circularly washing the well, and removing well wall mud and well bore impurities;

s500, after well flushing is completed, releasing is completed, an upper pipe column is lifted out, and open flow and liquid drainage are performed; the temporary plugging pieces of the temporary plugging screen pipe left under the well are dissolved, and the screen pipe recovers the flowing capacity and the supporting function.

S600, in the later-stage well repairing process, a special fishing tool is put in to fish out the rotatable releasing device, then a drilling and grinding tool is put in to directly drill and grind part of elements, the safety joint, the temporary plugging sieve tube and the flushing head of the rotatable releasing device left in the well, the shaft is restored again, and secondary well completion is carried out.

Furthermore, the plugging removal liquid can adopt the completion liquid, the acid liquid, the mud cake dissolving liquid and the lubricant of the original well.

Further, the releasing step in step S500 is specifically as follows:

firstly, throwing a ball into the rotatable releasing device, pressing the ball after the ball falls into the valve seat, shearing a pin at the upper part of the piston by pressure, driving the outer sleeve and the upper cone to move downwards by the downward movement of the piston, expanding two ends of the slot expansion sleeve under the extrusion action of the upper cone and the lower cone, and enabling the slot expansion sleeve to be tightly attached to the inner wall of the sleeve, thereby achieving the effect of hanging and supporting a lower tubular column; after the upper cone body descends, the opening ratchet retainer ring is clamped on the inverted teeth in the middle of the lower cone body, so that the sleeve can be prevented from loosening during hanging;

then, continuously pressurizing, wherein as the pin pressure bearing of the valve seat is larger than the pin pressure bearing of the piston, when the pressure is further increased, the pin of the valve seat is sheared off, and the sliding down of the valve seat is caught by the lower end enclosure; lifting the upper pipe column, enabling the fixture block and the ball to fall into the valve seat, separating the mandrel from the lower cone, lifting the mandrel together with the valve seat, the cylinder sleeve and the outer sleeve, and clamping the lower cone in the outer sleeve to realize releasing and separating of the upper pipe column;

further, in the releasing step in the step S500, if the upper suspension support is not needed, the upper pressure hole of the mandrel can be blocked, the ball is thrown and pressed, the upper portion is not supported, so that only the lower valve seat pin is cut off, and the bottom of the well is used for supporting the tubular column.

The invention has the advantages that:

(1) the holes of the sieve tube are blocked by the temporary blocking pieces, so that the circular washing of the sieve tube section is realized, and the condition that the sieve tube section is blocked is favorably treated;

(2) after the screen pipe completion pipe column is put in place, the circulating well washing of the whole well section can be realized, well wall mud cakes and shaft impurities are effectively removed, and the reservoir is protected;

(3) the clamping block of the rotatable releasing device is fixed in a plurality of discontinuous grooves, so that the lower cone can be limited to rotate along with the mandrel, and the lower pipe column can be driven to rotate by rotating the upper pipe column, so that the shaft bottom rotary drilling tool is unlocked;

(4) the temporary plugging sieve tube and the rotatable releasing device are matched for use, and the problems that the prior art is difficult to handle and can not be put in place at one time when being seriously blocked and blocked can be effectively solved by utilizing the dual functions of flushing and rotating the tubular column;

(5) the temporary plugging sieve tube and the flushing head are made of easily-drilled and abraded materials, a sieve tube well completion pipe column does not need to be fished in later-stage well repair, the sieve tube and the flushing head can be directly drilled and abraded, well repair difficulty and operation cost are reduced, and time is saved.

Drawings

FIG. 1 is a schematic diagram of a carbonate well screen completion string according to an embodiment;

FIG. 2 is a schematic structural view of a rinsing head according to an embodiment;

FIG. 3 is a schematic structural view of a temporary plugging screen according to an embodiment;

FIG. 4 is an enlarged schematic view of an embodiment of a temporary plugging screen hole;

fig. 5 is a schematic structural diagram of a rotatable releasing device provided by the embodiment.

The figures are labeled as follows:

1, a rotatable releasing device, 2 a safety joint, 3 a temporary plugging sieve tube, 4 a flushing head and 5 an easily drilled and ground oil pipe;

101 mandrel, 102 cylinder sleeve, 103 piston, 104 outer cylinder, 105 opening ratchet collar, 106 upper cone, 107 lower cone, 108 expansion sleeve, 109 fixture block, 110 valve seat, 111 lower joint and 112 lower end socket;

301 base pipe, 302 coupling, 303 temporary plugging sheet, 304 sealing ring and 305 pressure ring;

401 thread button, 402 water hole.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

As shown in figure 1, the completion pipe string of the carbonate oil well screen pipe comprises a rotatable releasing device 1, a safety joint 2, a temporary plugging screen pipe 3 and a flushing head 4 which are connected from top to bottom;

as shown in fig. 5, the rotatable releasing tool 1 comprises a mandrel 101, a cylinder sleeve 102, a piston 103, an outer cylinder 104, a split ratchet collar 105, an upper cone 106, a lower cone 107, an expansion sleeve 108, a fixture block 109, a valve seat 110, a lower joint 111 and a lower seal head 112; the cylinder sleeve 102, the piston 103, the lower cone 107 and the lower joint 111 are sequentially nested outside the mandrel 101 from top to bottom; the piston 103, the cylinder sleeve 102 and the mandrel 101 are sealed, so that a sealed hollow cavity is formed inside the mandrel 101; the piston 103 is fixedly connected with the mandrel 101 through a shearable pin; the lower joint 111 is fixedly connected with the lower end of the lower cone 107; the outer cylinder 104, the open ratchet collar 105, the upper cone 106 and the expansion sleeve 108 are all nested outside the lower cone 107; the outer wall of the middle part of the lower cone 107 is provided with a pawl structure, and the inner part of the middle lower part of the lower cone 107 is provided with a plurality of discontinuous grooves; a plurality of holes are formed in the body of the middle lower part of the mandrel 101, and the positions and the sizes of the holes correspond to those of the grooves of the lower cone 107; the fixture block 109 is positioned in a groove of the lower cone 107 and an eyelet of the mandrel 101, and the lower end enclosure 112 is fixedly connected to the lower end of the mandrel 101;

as shown in fig. 3 and 4, the temporary plugging screen pipe 3 comprises a base pipe 301, a coupling 302, a temporary plugging sheet 303, a sealing ring 304 and a pressing ring 305; the base pipe 301 adopts a circular pipe column, holes are uniformly drilled on the pipe body, and temporary plugging sheets 303 are arranged in the holes.

The safety joint 2, the flushing head 4 and the temporary plugging sieve tube 3 are all made of materials easy to drill and grind.

The valve seat 110 is fixed inside the core shaft 101 through a pin capable of being sheared, and the fixture block 109 is pressed into the groove of the lower cone 107, so that the connection of the fixture block 109 to the groove of the lower cone 107 and the hole of the core shaft 101 is realized.

The inner diameter of the lower end socket 112 is smaller than the outer diameter of the valve seat 110.

The holes of the temporary plugging screen pipe 3 comprise two parts with different diameters, which are respectively used as a first hole and a second hole. The first hole is positioned on the inner side of the pipe body, the second hole is positioned on the outer side of the pipe body, and the diameter of the second hole is larger than that of the first hole; the step is arranged between the first hole and the second hole and used for supporting the temporary plugging sheet 303, a groove is formed in the step, the sealing ring 304 is located in the groove of the step, then the temporary plugging sheet 303 is placed in the second hole, and the pressing ring 305 is fixed to the upper portion of the second hole and used for pressing the temporary plugging sheet 303 on the step.

In the temporary plugging sieve tube 3, the temporary plugging sheet 303 is made of a polymer material which is soluble in formation fluid, such as polyester BA1-28, and the compression strength is required to be more than 5 MPa; in the temporary plugging sieve tube 3, the base tube 301 and the pressure ring 305 are made of aluminum alloy materials easy to drill and grind.

The flushing head 4 is a hollow cylinder, the bottom of the flushing head is of an ellipsoidal structure, a plurality of water holes 402 are formed in the bottom of the flushing head and used for flushing the stratum, and a threaded buckle 401 is arranged at the upper end of the flushing head and enables the flushing head to be connected with the temporary plugging sieve tube 3.

Aiming at the completion pipe string of the carbonate rock oil well screen pipe, the unfreezing method comprises the following steps:

s100, respectively assembling and forming the rotatable releasing device 1 and the temporary plugging sieve tube 3 to meet the requirements of connection and sealing standards;

s200, connecting the rotatable releasing device 1, the safety joint 2, the temporary plugging sieve tube 3 and the flushing head 4 from top to bottom to form a sieve tube well completion pipe column, adopting a drill rod or an oil pipe as an upper pipe column, connecting the sieve tube well completion pipe column to the bottom of the upper pipe column through the rotatable releasing device, and lowering the sieve tube well completion pipe column into the well bottom by utilizing the upper pipe column;

s300, in the process of descending, once blockage and blockage occur, releasing blockage, wherein the releasing blockage operation is carried out by adopting a large-displacement forward circulation or reverse circulation flushing of a blockage removing liquid, and the blockage removing liquid can adopt a well completion liquid, an acid liquid, a mud cake dissolving liquid and a lubricating agent of an original well; because the screen pipe hole is in a temporary plugging state, the plugging removing liquid can circulate to the bottom of the well and is sprayed out or enters through the flushing head 4, so that the flushing liquid can effectively flush the blockage and the blockage points; simultaneously, the wellhead rotates the upper pipe column to drive the lower pipe column to rotate, the lower pipe column rotates while washing, and the lower pipe column is slowly lifted up until the completion pipe column is unfreezed; s400, after the screen pipe completion pipe string is successfully put into the well bottom, circularly washing the well, and removing well wall mud and well bore impurities;

s500, after well flushing is completed, releasing operation is carried out, firstly, the rotatable releasing device 1 is thrown with balls, after the balls fall into the valve seat 110, the balls are pressed, the pin at the upper part of the piston 103 is cut off by pressure, the piston 103 descends to drive the outer cylinder 104 and the upper cone 106 to descend, under the extrusion action of the lower cone 107 of the upper cone 106106, two ends of the slot expansion sleeve 108 expand to be tightly attached to the inner wall of the casing pipe, and therefore the effect of hanging and supporting the lower pipe column is achieved; after the upper cone 106 descends, the open ratchet retainer ring 105 is clamped on the inverted teeth in the middle of the lower cone 107, so that the sleeve is ensured not to be loosened; then, the pressure is continuously exerted, because the pin pressure bearing of the valve seat 110 is greater than the pin pressure bearing of the piston 103, when the pressure is further increased, the pin of the valve seat 110 is sheared off, and the valve seat 110 slides downwards to be received by the lower end enclosure 112; lifting the upper pipe column, enabling the fixture block 109 and the ball to fall into the valve seat 110, separating the mandrel 101 from the lower cone 107, lifting the mandrel 101 together with the valve seat 110, the cylinder sleeve 102 and the outer cylinder 104, and clamping the lower cone 107 in the outer cylinder 104 to realize releasing and separating of the upper pipe column; and lifting out the upper pipe column, and discharging liquid; the temporary plugging pieces 303 of the temporary plugging screen pipe 3 left under the well are dissolved and the screen pipe recovers the flow capacity and the supporting function.

S600, in the later-stage well repairing process, a special fishing tool is put in to fish out the rotatable releasing device 1, then a drilling and grinding tool is put in to directly drill and grind part of elements, the safety joint 2, the temporary plugging sieve tube 3 and the flushing head 4 of the rotatable releasing device 1 left in the well, the shaft is restored again, and secondary well completion is carried out.

Further, in the releasing step in the step S500, if the upper suspension support is not needed, the upper pressure hole of the mandrel 101 may be blocked, the ball is thrown and pressed, the upper portion is not supported, so that only the lower valve seat 110 pin is sheared, and the bottom of the well is used to support the pipe string.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.