阅读说明：本技术 一种重复试压开启式趾端滑套及其使用方法 (Repeated pressure test opening type toe end sliding sleeve and using method thereof ) 是由 曹存才 鄢红江 谢威 杨礼 于 2021-08-04 设计创作，主要内容包括：本发明提供了一种重复试压开启式趾端滑套及其使用方法,包括筒体、芯轴、剪切套、换级座、弹簧和下接头,芯轴安装在筒体的内孔中,剪切套、换级座、弹簧和下接头端部依次套装在芯轴外圈与筒体内孔之间,剪切套抵靠住轴肩的另一侧,下接头与筒体内孔的一端孔口固定连接,芯轴与筒体和下接头之间均为轴向滑动密封连接,筒体上固定有剪切螺钉,剪切螺钉插入剪切套中,换级座外圈设置有多段连续人字形折返的导槽,筒体上固定有导向柱,导向柱端部插入导槽中。本发明提供了一种重复试压开启式趾端滑套及其使用方法,在满足压裂施工前套管强度试压作业需求的同时,又具有了可实现井筒与地层有效沟通的趾端滑套的功能。(The invention provides a repeated pressure test open type toe end sliding sleeve and a using method thereof, and the repeated pressure test open type toe end sliding sleeve comprises a barrel, a mandrel, a shearing sleeve, a grade changing seat, a spring and a lower connector, wherein the mandrel is arranged in an inner hole of the barrel, the end parts of the shearing sleeve, the grade changing seat, the spring and the lower connector are sequentially sleeved between an outer ring of the mandrel and the inner hole of the barrel, the shearing sleeve abuts against the other side of a shaft shoulder, the lower connector is fixedly connected with an orifice at one end of the inner hole of the barrel, the mandrel, the barrel and the lower connector are in axial sliding sealing connection, a shearing screw is fixed on the barrel and inserted into the shearing sleeve, a plurality of sections of guide grooves which are continuously folded back in a herringbone shape are arranged on the outer ring of the grade changing seat, a guide column is fixed on the barrel, and the end part of the guide column is inserted into the guide grooves. The invention provides a repeated pressure test open-type toe end sliding sleeve and a using method thereof, which meet the requirement of casing strength pressure test operation before fracturing construction and have the function of the toe end sliding sleeve capable of realizing effective communication between a shaft and a stratum.)

1. The utility model provides a hole that axial link up is seted up to repeated pressure testing open-type toe end sliding sleeve, the center, its characterized in that: comprises a cylinder body (2), a mandrel (3), a shearing sleeve (4), a grading seat (6), a spring (11) and a lower joint (12), wherein the mandrel (3) is arranged in an inner hole of the cylinder body (2), a shaft shoulder (301) is arranged on the outer ring of the mandrel (3), one end of the inner hole of the cylinder body (2) is provided with a hole shoulder (201), one side of the shaft shoulder (301) is abutted against the hole shoulder (201), the shearing sleeve (4), the grading seat (6), the spring (11) and the end part of the lower joint (12) are sequentially sleeved between the outer ring of the mandrel (3) and the inner hole of the cylinder body (2), the shearing sleeve (4) is abutted against the other side of the shaft shoulder (301), the lower joint (12) is fixedly connected with an orifice at one end of the inner hole of the cylinder body (2), the mandrel (3) is in axial sliding sealing connection with the cylinder body (2) and the lower joint (12), a shearing screw (5) is fixed on the cylinder body (2), and the shearing screw (5) is inserted into the shearing sleeve (4), the outer ring of the stage changing seat (6) is provided with a plurality of sections of guide grooves (601) which are continuously folded back like a Chinese character 'ji', one end of each guide groove (601) is closed, the other end of each guide groove (601) is axially opened along the stage changing seat (6), the opening end of the guide groove (601) is arranged at one side of the shearing sleeve (4), a guide post (7) is fixed on the cylinder body (2), the end part of the guide post (7) is inserted into the guide groove (601), and the guide post (7) is positioned at the bottom of the closed end of the guide groove (601), a plurality of fracturing holes (202) are arranged on the hole shoulder (201) of the cylinder body (2), the fracturing holes (202) are shielded by the end part of the mandrel (3) from the inner side, the guide post (7) is repeatedly pressurized and decompressed in the inner cavity of the sliding sleeve at the toe end, the guide post (7) moves from the closed end to the open end along the guide groove (601), before entering the last section of the guide groove (601), the end part of the mandrel (3) and the fracturing hole (202) are kept in a completely shielding state, and a sealing state is kept between the mandrel (3) and the barrel body (2).

2. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 1, wherein: the strength of the shear screw (5) meets the requirement that the shear screw is not sheared by the shear sleeve (4) when cement is squeezed and injected in a well cementation way.

3. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 1, wherein: guide slot (601) include the slide that the multistage was turned back, the one end that every section slide is close to guide slot (601) blind end is the initiating terminal, the other end that every section slide is close to guide slot (601) open end is the terminal, the terminal of every section slide is provided with spacing pit (601f) that holds guide post (7), spacing pit (601f) opening is just right the initiating terminal of next section slide along the axial, shearing sleeve (4) are provided with one spacing hole (401) and a plurality of and offer the spacing spout that just length increases one by one along the axial, respectively cartridge a shear screw (5) in spacing hole (401) and every spacing spout, spacing hole (401), the positional relation of spacing spout and spacing pit (601f) satisfies in every toe end sliding sleeve inner chamber pressure testing pressurization process, cut shear screw (5) at most.

4. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 3, wherein: guide slot (601) include five sections slides, the initiating terminal of first section slide is the blind end of guide slot (601), the terminal of fifth section slide is the open end of guide slot (601), spacing spout includes first spacing spout (402) and second spacing spout (403), shear screw (5) are including first shear screw (501), second shear screw (502) and third shear screw (503), first shear screw (501) are inserted with spacing hole (401) and are closed, first spacing spout (402) are inserted in second shear screw (502), second shear screw (503) insert second spacing spout (403).

5. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 1, wherein: the number of the guide grooves (601) is at least two, and the guide grooves are uniformly distributed along the circumferential direction of the outer ring of the stage changing seat (6).

6. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 1, wherein: be provided with bearing ring (9) between seat (6) and spring (11) of trading the level, bearing ring (9) are including two rings along the axial setting, and two rings are supported respectively and are leaned on seat (6) and spring (11) of trading the level, are provided with ball or kingpin between two rings and make two rings can rotate relatively around the axial.

7. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 1, wherein: the stage changing seat (6) is in clearance fit with the mandrel (3), and a plurality of wear-resistant rings (10) are arranged between the stage changing seat (6) and the mandrel (3).

8. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 1, wherein: the annular groove (302) has been seted up on shaft shoulder (301), be provided with circlip (8) in annular groove (302), make guide post (7) deviate from guide slot (601) from the open end in pressure testing pressurization process, stagger completely until dabber (3) tip and fracturing hole (202), barrel (2) hole corresponds circlip (8) position this moment and is provided with step hole (203), circlip (8) outer lane expandes the card and stays in annular groove (302) at the bottom of step hole (203) and the inner circle carries out axial spacing to dabber (3).

9. The opening toe end sliding sleeve for repeated pressure test as claimed in claim 1, wherein: one end of the mandrel (3) is provided with a mud scraping ring (13), and the outer ring of the mud scraping ring (13) is attached to the inner cavity of the lower joint (12).

10. A method of using a repetitively pressure-tested open-type toe end sleeve, using the toe end sleeve of any one of claims 1 to 9, comprising the steps of:

the method comprises the following steps: the number of times of turning back the guide groove (601) of the replacement-stage seat (6) and the number of the shearing screws (5) are set according to the number of times of pressure test after well cementation, the number of the shearing screws (5) is the same as the number of times of pressure test, and the number of the slide ways turned back by the guide groove (601) is equal to two times of the number of times of pressure test minus one;

step two: installing the toe end sliding sleeve on a well cementing tool, putting the toe end sliding sleeve into a well drilled with a hole, and squeezing cement to finish well cementing;

step three: after well cementation is finished, pressure testing is carried out, pressure testing liquid is pumped in through ground pressure equipment, the pumping pressure is gradually increased according to the requirement of the pressure testing times, one shearing screw (5) is sheared off each time of pressure testing, after all pressure testing is finished, a guide column (7) enters the last section of a guide groove (601), all the shearing screws (5) are sheared off, and no limit exists in the axial direction;

step four: and continuously pressurizing to enable the guide post (7) to be separated from the guide groove (601) until the end part of the mandrel (3) is completely staggered with the fracturing hole (202), the outer ring of the elastic retainer ring (8) is unfolded and clamped at the bottom of the hole of the stepped hole (203), and the inner ring of the elastic retainer ring is left in the annular groove (302) to axially limit the mandrel (3).

Technical Field

The invention belongs to the field of downhole tools for fracturing operation of oil and gas wells, and particularly relates to a repeated pressure test opening type toe end sliding sleeve and a using method thereof.

Background

The toe end sliding sleeve tool is a rapid and efficient downhole tool which is free of perforation and used for opening a stratum, a preset position is set into the toe end sliding sleeve along with a well completion casing pipe, well cementation operation is carried out, the toe end sliding sleeve is directly opened through pressure build-up of a shaft during fracturing construction, and first-stage fracturing construction operation is directly carried out through injection of a light casing pipe. The tool can quickly and efficiently realize the communication between the shaft and the stratum, and quickly and efficiently solve the problem of first-layer perforation and fracturing of a casing sliding sleeve stratified section fracturing and bridge shooting combined staged fracturing process, particularly the difficult problem of first-section perforation of an ultra-long horizontal well which exceeds the lower depth of an oil pipe. However, the toe sliding sleeve tool is opened by the build-up pressure in the casing, which conflicts with the operation of pressure testing for casing strength before fracturing construction of a new well. In order to solve the problems, the chinese patent with publication number CN207999237U provides a pressure-testable toe end sliding sleeve, which comprises a casing and an inner sliding sleeve arranged in the casing, wherein the inner sliding sleeve can axially slide in the casing; the shell comprises an upper joint, an upper shell, a lower shell and a lower joint, external threads and a flow limiting valve cylinder are arranged on the outer wall of the upper inner sliding sleeve, the external threads are connected with the upper inner sliding sleeve and the flow limiting valve cylinder, a flow limiting valve is arranged in the flow limiting valve cylinder, and a rupture disc, an inner sliding sleeve boss and a fixing ring are arranged on the side wall of the lower inner sliding sleeve; an oil cavity is arranged between the upper shell and the lower inner sliding sleeve, and an air cavity is arranged between the lower shell and the lower inner sliding sleeve; the lower end of the lower shell is provided with the limiting groove, so that the sliding sleeve can be prevented from being fixed by well cementing cement in a well cementing process, the sliding sleeve can not be opened in a pressure testing process aiming at a well cementing casing after the well cementing is completed, the pressure testing result of the well cementing casing can not be influenced, and the operation requirement of repeated pressure testing can not be met.

Disclosure of Invention

In order to solve the technical problems, the invention provides a repeated pressure test opening type toe end sliding sleeve and a using method thereof, which meet the requirement of casing strength pressure test operation before fracturing construction and have the function of the toe end sliding sleeve capable of realizing effective communication between a shaft and a stratum.

The invention is realized by the following technical scheme:

a repeated pressure test open type toe end sliding sleeve and a using method thereof, wherein the center is provided with an axially through hole, the repeated pressure test open type toe end sliding sleeve comprises a barrel body, a mandrel, a shearing sleeve, a grade changing seat, a spring and a lower connector, the mandrel is arranged in an inner hole of the barrel body, a shaft shoulder is arranged on an outer ring of the mandrel, one end of the inner hole of the barrel body is provided with the hole shoulder, one side of the shaft shoulder is abutted against the hole shoulder, the end parts of the shearing sleeve, the grade changing seat, the spring and the lower connector are sequentially sleeved between the outer ring of the mandrel and the inner hole of the barrel body, the shearing sleeve is abutted against the other side of the shaft shoulder, the lower connector is fixedly connected with an orifice at one end of the inner hole of the barrel body, the mandrel, the barrel body and the lower connector are in axial sliding sealing connection, the shearing screw is fixed on the barrel body and inserted into the shearing sleeve, the outer ring of the grade changing seat is provided with a plurality of sections of guide grooves which are continuously inverted V-shaped, one end of the guide grooves is closed, the other end of the guide grooves is axially opened at one side of the shearing sleeve, the guide post is fixed on the barrel, the end part of the guide post is inserted into the guide groove, the guide post is positioned at the bottom of the closed end of the guide groove, a plurality of fracturing holes are formed in the hole shoulder of the barrel, the end part of the mandrel shields the fracturing holes from the inner side, the guide post moves from the closed end to the open end along the guide groove in the repeated pressurization and pressure relief processes of the inner cavity of the toe end sliding sleeve, and before the guide post enters the last section of the guide groove, the end part of the mandrel and the fracturing holes are kept in a completely shielding state, and the sealing state is kept between the mandrel and the barrel. The operation requirement of repeated pressure testing is realized, the sliding sleeve cannot be opened in the pressure testing process, the pressure testing result of the well cementation casing pipe cannot be influenced, the requirement of casing pipe strength pressure testing operation before fracturing construction is met, and meanwhile, the toe end sliding sleeve has the function of realizing the toe end sliding sleeve for effectively communicating a shaft and a stratum.

The strength of the shear screw meets the requirement that the shear screw cannot be sheared by the shear sleeve when cement is squeezed and injected in a well cementation process, and the sliding sleeve cannot move due to the limit of the shear screw in the well cementation process.

The guide slot includes the slide that the multistage was turned back, the one end that every section slide is close to the guide slot blind end is the initiating terminal, the other end that every section slide is close to the guide slot open end is the terminal, the terminal of every section slide is provided with the spacing pit that holds the guide post, spacing pit opening is just to the initiating terminal of next section slide along the axial, the shearing cover is provided with a spacing spout that spacing hole and a plurality of offered and length increase one by one along the axial, shear screw of difference cartridge in spacing hole and every spacing spout, spacing hole, the positional relation of spacing spout and spacing pit satisfies at every toe end sliding sleeve inner chamber pressure testing pressurization in-process, only cut a shear screw at most. When pressure testing reaches the pressure requirement each time, a shearing screw is sheared to enable the guide column to enter the next slideway, and when the pressure is insufficient, the pressure is relieved, and the guide column returns to the limiting pit of the previous slideway, so that the pressure testing is ensured to meet the testing requirement.

Preferably, the guide slot includes five sections slides, and the initiating terminal of first section slide is the blind end of guide slot, and the terminal of fifth section slide is the open end of guide slot, and spacing spout includes first spacing spout and the spacing spout of second, and shear screw includes first shear screw, second shear screw and third shear screw, and first shear screw and spacing hole plug-in fit, second shear screw insert first spacing spout, and third shear screw inserts the spacing spout of second, satisfies the operation demand of cubic pressure testing.

The number of the guide grooves is at least two, the guide grooves are uniformly distributed along the circumferential direction of the outer ring of the stage changing seat, and the stress is uniform.

Be provided with the bearing ring between seat and the spring of trading, the bearing ring includes two rings that set up along the axial, and two rings support respectively and lean on seat and spring of trading, are provided with ball or kingpin between two rings and make two rings can rotate around the axial relatively, make the seat of trading can smoothly rotate around the mandrel axial, guarantee that the guide post slides smoothly.

The stage changing seat is in clearance fit with the mandrel, and a plurality of wear-resisting rings are arranged between the stage changing seat and the mandrel, so that the rotation resistance is reduced, and the rotation is smoother.

The annular has been seted up on the shaft shoulder, be provided with the circlip in the annular, make the guide post deviate from the guide slot from the open end in pressure testing pressurization process, stagger completely with the fracturing hole until mandrel tip, the barrel hole corresponds circlip position this moment and is provided with the step hole, the circlip outer lane expandes the card and is detained in the annular at step hole bottom and inner circle and carry out the axial spacing to the mandrel, after accomplishing all pressure testing, can prevent that the mandrel from reseing under the condition of not hitting pressure, fracturing fluid sprays the fracturing immediately towards the fracturing hole of seting up in advance on the barrel. That is, the first section of the whole pipe column can be realized to connect the oil production layer and the gas production layer to the channel in the pipe column.

One end of the mandrel is provided with a mud scraping ring, and the outer ring of the mud scraping ring is attached to the inner cavity of the lower connector.

The other end of the cylinder body is fixedly connected with an upper joint.

The application also provides a method for using the repeated pressure test open-type toe end sliding sleeve, and any toe end sliding sleeve is used, and the method comprises the following steps:

the method comprises the following steps: setting the turn-back times of the guide groove of the replacement-stage seat and the number of shearing screws according to the times of well cementation after pressure test, wherein the number of the shearing screws is the same as the number of the pressure test, and the number of the slide ways turned back by the guide groove is equal to two times of the number of the pressure test minus one;

step two: installing the toe end sliding sleeve on a well cementing tool, putting the toe end sliding sleeve into a well drilled with a hole, and squeezing cement to finish well cementing;

step three: after the well cementation is finished, performing pressure test, pumping pressure test liquid through ground pressure equipment, gradually increasing the pumping pressure according to the requirement of the pressure test times, shearing one shear screw each time the pressure test is finished, enabling the guide column to enter the last section of the guide groove after all the pressure tests are finished, shearing all the shear screws, and having no limit in the axial direction;

step four: and continuously pressurizing to enable the guide column to be separated from the guide groove until the end part of the mandrel is completely staggered with the fracturing hole, and the outer ring of the elastic retainer ring is unfolded and clamped at the bottom of the stepped hole and the inner ring of the elastic retainer ring is left in the ring groove to axially limit the mandrel.

The invention has the beneficial effects that:

compared with the prior art, the operation requirement of repeated pressure testing for many times is met, the sliding sleeve cannot be opened in the pressure testing process, the pressure testing result of the well cementation casing pipe cannot be influenced, all the shearing screws are cut off after the pressure testing is completed, the mandrel is not limited in the axial direction, the sliding sleeve can be opened through pressurization, the fracturing holes are completely exposed, the mandrel is fixed through the elastic retaining ring, the mandrel is prevented from resetting under the condition that the fracturing liquid is not pressed, and the fracturing liquid is sprayed and fractured towards the fracturing holes which are formed in the barrel in advance. The first section in the whole tubular column that can realize promptly connects the passageway in oil production, gas production layer to the tubular column, when satisfying casing strength pressure testing operation demand before the fracturing construction, has had the toe end sliding sleeve's that can realize pit shaft and stratum effective communication function again.

Drawings

FIG. 1 is a schematic diagram of an initial state in an embodiment of the present invention;

FIG. 2 is an enlarged view of the structure at I in FIG. 1;

FIG. 3 is a schematic structural diagram of the embodiment of the invention after pressure testing is completed;

FIG. 4 is a schematic structural view of a cartridge in an embodiment of the present invention;

FIG. 5 is a schematic illustration of the construction of a shear sleeve in an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a stage changing base according to an embodiment of the present invention;

FIG. 7 is a schematic view of a third pressure test state in an embodiment of the present invention.

In the figure: 1-upper joint, 2-barrel, 3-mandrel, 4-shearing sleeve, 5-shearing screw, 6-step changing seat, 7-guide column, 8-elastic retainer ring, 9-bearing ring, 10-wear-resisting ring, 11-spring, 12-lower joint, 13-mud scraping ring,

201-hole shoulder, 202-fracturing hole, 203-step hole, 204-shear pin mounting hole, 205-guide post mounting hole,

301-a shaft shoulder, 302-a ring groove,

401-a limit hole, 402-a first limit chute, 403-a second limit chute,

501-first shear screw, 502-second shear screw, 503-third shear screw,

601-a guide groove, 601 a-a first section of slide way, 601 b-a second section of slide way, 601 c-a third section of slide way, 601 d-a fourth section of slide way, 601 e-a fifth section of slide way and 601 f-a limiting pit,

Detailed Description

The technical solution of the present invention is further described below, but the scope of the claimed invention is not limited to the described.

As shown in fig. 1 to 7, a repeated pressure test open type toe end sliding sleeve, the center of which is provided with an axially through hole, comprises a barrel body 2, a mandrel 3, a shearing sleeve 4, a stage changing seat 6, a spring 11 and a lower joint 12, wherein the mandrel 3 is arranged in an inner hole of the barrel body 2, the outer ring of the mandrel 3 is provided with a shaft shoulder 301, one end of the inner hole of the barrel body 2 is provided with the hole shoulder 201, one side of the shaft shoulder 301 is abutted against the hole shoulder 201, the ends of the shearing sleeve 4, the stage changing seat 6, the spring 11 and the lower joint 12 are sequentially sleeved between the outer ring of the mandrel 3 and the inner hole of the barrel body 2, the shearing sleeve 4 is abutted against the other side of the shaft shoulder 301, the lower joint 12 is fixedly connected with one end hole opening of the inner hole of the barrel body 2, the mandrel 3 is axially connected with the barrel body 2 and the lower joint 12 in a sliding sealing manner, the shearing screw 5 is fixed on the barrel body 2, the shearing screw 5 is inserted into the shearing sleeve 4, the outer ring of the stage changing seat 6 is provided with a plurality of continuously inverted herringbone guide grooves 601, one end of the guide groove 601 is closed, the other end of the guide groove 601 is axially opened along the grading seat 6, the open end of the guide groove 601 is arranged on one side of the shearing sleeve 4, a guide post 7 is fixed on the cylinder body 2, the end part of the guide post 7 is inserted into the guide groove 601, the guide post 7 is positioned at the bottom of the closed end of the guide groove 601, a plurality of fracturing holes 202 are formed in a hole shoulder 201 of the cylinder body 2, the fracturing holes 202 are shielded by the end part of the mandrel 3 from the inner side, the guide post 7 moves from the closed end to the open end along the guide groove 601 in the repeated pressurization and pressure relief processes of the inner cavity of the toe end sliding sleeve, before the guide post 7 enters the last section of the guide groove 601, the end part of the mandrel 3 and the fracturing holes 202 are kept in a completely shielded state, and the sealing state is kept between the mandrel 3 and the cylinder body 2.

The strength of the shear screw 5 meets the requirement that the shear screw is not sheared by the shear sleeve 4 when cement is squeezed and injected in a well cementation way.

As shown in fig. 5 to 7, the guide slot 601 includes multiple sections of folded slideways, one end of each section of slideway close to the closed end of the guide slot 601 is a starting end, the other end of each section of slideway close to the open end of the guide slot 601 is a terminal, a limiting pit 601f for accommodating the guide post 7 is arranged at the terminal of each section of slideway, the opening of the limiting pit 601f is axially opposite to the starting end of the next section of slideway, the shearing sleeve 4 is provided with a limiting hole 401 and a plurality of limiting sliding grooves which are axially arranged and the length of which is increased one by one, a shearing screw 5 is respectively inserted into the limiting hole 401 and each limiting sliding groove, and the positional relationship among the limiting hole 401, the limiting sliding groove and the limiting pit 601f satisfies that in the pressure test and pressurization process of the inner cavity of the sliding sleeve at the toe end, at most one shearing screw 5 is cut off.

As shown in fig. 5 to 7, the guide slot 601 includes five sections of slide ways, the starting end of the first section of slide way is the closed end of the guide slot 601, the terminal end of the fifth section of slide way is the open end of the guide slot 601, the limiting slide way includes a first limiting slide way 402 and a second limiting slide way 403, the shear screw 5 includes a first shear screw 501, a second shear screw 502 and a third shear screw 503, the first shear screw 501 is inserted into the limiting hole 401, the second shear screw 502 is inserted into the first limiting slide way 402, and the third shear screw 503 is inserted into the second limiting slide way 403.

The number of the guide grooves 601 is at least two, and the guide grooves are uniformly distributed along the circumferential direction of the outer ring of the stage changing seat 6.

As shown in fig. 1 to 3, a bearing ring 9 is disposed between the stage changing seat 6 and the spring 11, the bearing ring 9 includes two rings disposed along the axial direction, the two rings respectively abut against the stage changing seat 6 and the spring 11, and balls or needles are disposed between the two rings to enable the two rings to relatively rotate around the axial direction.

The stage changing seat 6 is in clearance fit with the mandrel 3, and a plurality of wear-resisting rings 10 are arranged between the stage changing seat 6 and the mandrel 3.

As shown in fig. 1 to 3, a ring groove 302 is formed in the shaft shoulder 301, a circlip 8 is disposed in the ring groove 302, the guide post 7 is separated from the guide groove 601 from the opening end in the pressure testing and pressurizing process until the end of the mandrel 3 is completely staggered with the fracturing hole 202, a step hole 203 is disposed in the inner hole of the cylinder 2 corresponding to the circlip 8, the outer ring of the circlip 8 is unfolded and clamped at the bottom of the step hole 203, and the inner ring is left in the ring groove 302 to axially limit the mandrel 3.

And a mud scraping ring 13 is arranged at one end of the mandrel 3, and the outer ring of the mud scraping ring 13 is attached to the inner cavity of the lower joint 12.

The other end of the cylinder body 2 is fixedly connected with an upper joint 1.

The use method of the repeated pressure test opening type toe end sliding sleeve comprises the following steps:

the method comprises the following steps: the number of times of turning back of the guide groove 601 of the replacement-stage seat 6 and the number of 5 shearing screws are set according to the number of times of pressure test after well cementation, the number of 5 shearing screws is the same as the number of times of pressure test, and the number of the slide ways turned back by the guide groove 601 is equal to two times of the number of times of pressure test minus one;

step two: installing the toe end sliding sleeve on a well cementing tool, putting the toe end sliding sleeve into a well drilled with a hole, and squeezing cement to finish well cementing;

step three: after the well cementation is finished, performing pressure test, pumping pressure test liquid through ground pressure equipment, gradually increasing the pumping pressure according to the requirement of the pressure test times, shearing one shear screw 5 in each pressure test, enabling the guide column 7 to enter the last section of the guide groove 601 after all the pressure tests are finished, shearing all the shear screws 5, and having no limit in the axial direction;

step four: and continuously pressurizing to enable the guide post 7 to be separated from the guide groove 601 until the end part of the mandrel 3 is completely staggered with the fracturing hole 202, the outer ring of the elastic retainer ring 8 is unfolded and clamped at the bottom of the stepped hole 203, and the inner ring is left in the ring groove 302 to axially limit the mandrel 3.

Examples

As shown in fig. 1 to 6, a repeated pressure testing open-type toe end sliding sleeve, the hole that the axial link up is seted up at the center, including barrel 2, dabber 3, shearing sleeve 4, seat 6 changes the grade, spring 11 and lower clutch 12, dabber 3 is installed in the hole of barrel 2, 3 outer lanes of dabber are provided with shaft shoulder 301, 2 hole one ends of barrel are provided with hole shoulder 201, one side of shaft shoulder 301 supports and leans on hole shoulder 201, shearing sleeve 4, seat 6 changes the grade, spring 11 and 12 tip suits of lower clutch are between 3 outer lanes of dabber and 2 holes of barrel in proper order, shearing sleeve 4 supports and leans on the opposite side of shaft shoulder 301, the one end drill way fixed connection in lower clutch 12 and the barrel 2 hole, be axial sliding sealing connection between dabber 3 and barrel 2 and the lower clutch 12.

The guide groove 601 comprises five sections of folded slide ways, a first section of slide way 601a, a second section of slide way 601b, a third section of slide way 601c, a fourth section of slide way 601d and a fifth section of slide way 601e are sequentially connected end to end, the starting end of the first section of slide way 601a is a closed end of the guide groove 601, the terminal end of the fifth section of slide way 601e is an open end of the guide groove 601, one end of each section of slide way close to the closed end of the guide groove 601 is a starting end, the other end of each section of slide way close to the open end of the guide groove 601 is a terminal end, a limiting pit 601f for accommodating the guide post 7 is arranged at the terminal end of each section of slide way, the opening of the limiting pit 601f is opposite to the starting end of the next section of slide way along the axial direction, and the projection positions of the starting ends of the first section of slide way 601a, the third section of slide way 601c and the fifth section of slide way 601e are the same in the axial direction.

Three shear screws 5 are fixed on the barrel 2 and respectively comprise a first shear screw 501, a second shear screw 502 and a third shear screw 503, the shear sleeve 4 is provided with a limiting hole 401, a first limiting sliding groove 402 and a second limiting sliding groove 403, the first shear screw 501 is inserted into the limiting hole 401, the second shear screw 502 is inserted into the first limiting sliding groove 402, the third shear screw 503 is inserted into the second limiting sliding groove 403, and the length of the second limiting sliding groove 403 is larger than that of the first limiting sliding groove 402.

Initially, the guide post 7 is located at the starting end of the first section of the slideway 601a, and the guide post 7 can slide along the guide groove 601 only by shearing the first shear screw 501 under pressure; when the guide post 7 slides in the first section of slide way 601a, the second shear screw 502 freely slides in the first limit slide way 402 without shearing, and when the guide post 7 slides to the terminal end of the third section of slide way 601c, the first limit slide way 402 shears the second shear screw 502; when the guide post 7 slides in the first section slide way 601a to the third section slide way 601c, the third shear screw 503 slides freely in the second limit slide way 403 without shearing, and when the guide post 7 slides to the terminal end of the fifth section slide way 601e, the second limit slide way 403 shears the third shear screw 503.

The hole shoulder 201 of the barrel body 2 is provided with a plurality of fracturing holes 202, the end part of the mandrel 3 shields the fracturing holes 202 from the inner side, the guide post 7 moves from the closed end to the open end along the guide groove 601 in the repeated pressurization and pressure relief process of the inner cavity of the sliding sleeve at the toe end, before the guide post 7 enters the fifth section of slide way 601e, the end part of the mandrel 3 and the fracturing holes 202 are kept in a completely shielded state, and the sealing state is kept between the mandrel 3 and the barrel body 2.

The shaft shoulder 301 is provided with a ring groove 302, the ring groove 302 is internally provided with a circlip 8, the guide post 7 is separated from the guide groove 601 from the opening end in the pressure testing and pressurizing process until the end part of the mandrel 3 is completely staggered with the fracturing hole 202, the inner hole of the cylinder body 2 is provided with a step hole 203 corresponding to the position of the circlip 8 at the moment, the outer ring of the circlip 8 is unfolded and clamped at the bottom of the step hole 203, and the inner ring is left in the ring groove 302 to axially limit the mandrel 3.

The other end of the cylinder body 2 is fixedly connected with an upper joint 1.

The working principle is as follows:

as shown in figure 7, the toe end sliding sleeve and other well cementing tools are connected into a whole and are put into a well drilled with a hole, and like other tools, the well cementing sliding sleeve is internally provided with a water hole, and the inside and the outside are sealed without mutual interference. Therefore, installing the tool on a cementing string does not alter the cementing process. The toe end sliding sleeve is installed at the position close to the bottom end of the well cementation tubular column. After the well cementation pipe column is put in place, after relevant tests, well cementation cement begins to be injected, the cement enters an annular space between the well cementation pipe column and a stratum through a water hole of a well cementation float shoe after passing through a water hole of the well cementation pipe column, and the work of well cementation cement injection is completed when cement is pumped into a cement plug to return the cement to a designed height through cement squeezing. During cementing, the pin is not short enough due to pump pressure and liquid column pressure, so the sliding sleeve can not act.

After the well cementation is finished, pumping pressure testing liquid (such as clear water) by ground pressure equipment to reach the pressure testing pressure, and keeping for a specified time, wherein the pressure change value accords with the specification, namely, the well cementation tubular column is judged to be successfully tested. The toe end sliding sleeve is still in the initial position because the pressure is not reached to shear the first shear screw during well cementation.

During the pressure testing (the bottom has been sealed in the cased well), under the effect of pumping pressure and the liquid column pressure that the equipment of suppressing through the ground provided, because there is the area difference (big face down little above-mentioned) to lead to the dabber to move down on the dabber, drive and cut the cover, trade the seat, the bearing ring and remove compression spring together, when pressure is not enough to fix the shear screw on the barrel, when interior pressure unloads the back, the spring force resumes elastic deformation and cuts the cover, trade the seat, the bearing ring presses back initial position together. When the pressure reaches a value sufficient to shear the first shear screw (the second shear screw and the third shear screw are not stressed and only slide in the corresponding grooves), the guide post on the shifting seat slides according to the designed track, and when the pressure is removed, the guide post slides to the initial position (the circumferential position changes). When the pressure is tested for the second time (the pressure is increased), the first action is repeated, only the second shearing screw is sheared, the guide column (the axial direction returns to the initial position, and the circumferential position changes), and the sliding sleeve is still not opened due to the fact that the axial moving distance of the mandrel is insufficient. And (3) carrying out pressure test for the third time (pressure is increased), repeating the previous action, shearing a third shearing screw, shearing, and then, moving the shearing sleeve, the stage changing seat and the bearing ring together to compress the spring until the fracturing hole is completely opened without constraint, wherein all pressure acts on the spring, the mandrel moves downwards to drive the shearing sleeve, the stage changing seat and the bearing ring to move together until the fracturing hole is completely opened, at the moment, the axial moving distance of the mandrel is enough, the elastic check ring on the mandrel enters the stepped hole, the elastic check ring is not radially constrained, after elastic deformation is recovered, the outer ring is unfolded and clamped at the bottom of the stepped hole, and the inner ring is left in the annular groove, so that the mandrel can be prevented from resetting under the condition of no fracturing, and fracturing fluid immediately carries out jet fracturing towards the fracturing hole which is pre-opened on the cylinder body. That is, the first section of the whole pipe column can be realized to connect the oil production layer and the gas production layer to the channel in the pipe column.

The invention provides a repeated pressure test open-type toe end sliding sleeve and a using method thereof, which realize the operation requirement of repeated pressure tests, the sliding sleeve cannot be opened in the pressure test process, the pressure test result of a well cementation casing pipe cannot be influenced, all shearing screws are sheared after the pressure tests are finished, a mandrel is not limited in the axial direction, the sliding sleeve can be opened after pressurization, fracturing holes are exposed completely, the mandrel is fixed through an elastic retainer ring, the mandrel is prevented from resetting under the condition of no pressure test, and fracturing fluid is sprayed and fractured towards the fracturing holes which are pre-opened on a barrel body. The first section in the whole tubular column that can realize promptly connects the passageway in oil production, gas production layer to the tubular column, when satisfying casing strength pressure testing operation demand before the fracturing construction, has had the toe end sliding sleeve's that can realize pit shaft and stratum effective communication function again.