Shale gas well completion pipe string test nipple structure and use method

Abstract

This invention relates to a shale gas well completion tubing test section structure and its usage method. The structure includes a test section body with a first and second liquid inlet on its sidewall and an outlet on its outer sleeve. A guide groove structure is provided on the outer wall of the test section body, comprising n V-shaped grooves connected circumferentially, where n ≥ 3. The top of each V-shaped groove forms an upper limit point, and the bottom of each V-shaped groove forms a lower limit point. A sliding pin is connected to a piston and can move along the guide groove structure. When the sliding pin moves to the lower limit point of the nth V-shaped groove, the second liquid inlet and outlet connect. This invention can meet the technical requirements of rapid pressure testing and initial connection of shale gas wellbores. After pressure testing, initial fracturing can be carried out immediately, allowing pressure testing and connection procedures to proceed sequentially without interruption. It features good mechanical delay effect, short operation time, simple structure, high reliability, easy operation, and is economical and practical.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of staged fracturing completion, in particular to a shale gas well completion string pressure testing nipple structure and a use method thereof. BACKGROUND

[0002] Shale gas is natural gas filled in shale fissures, micro-pores and layers. Shale gas is usually extracted by first drilling a vertical well to several kilometers underground, then drilling horizontally for several hundred to thousands of kilometers, and using large-scale hydraulic fracturing technology, that is, by injecting a mixture of clean water, ceramic particles, chemicals and other fracturing fluids into the underground at a pressure of tens to hundreds of megapascals, the rock layer containing natural gas flow is "pried open", and the shale gas deeply buried in the shale layer is released, and finally the purpose of exploitation is achieved.

[0003] Staged fracturing technology is one of the key supporting technologies of horizontal wells. By using staged fracturing, multiple reservoirs can be fractured at one time in a short period of time, and the damage to the reservoirs is minimized, multi-layer production is achieved, and the purpose of improving single well production and maximizing the degree of geological reserves that can be produced is achieved.

[0004] The first stage fracturing construction of a shale gas well can generally be transmitted by coiled tubing perforation, or a conventional differential pressure opening device can be used to establish a communication channel between the wellbore and the formation. However, using coiled tubing for transmission perforation has problems such as long construction period, high cost and misperforation; using a conventional pressure opening communication device has high construction efficiency, low cost and small risk. However, the existing differential pressure opening communication device has the following technical defects:

[0005] (1) The current shale gas fracturing construction has the characteristics of high pressure, large displacement, continuity and long time, and the maximum construction pressure can reach 110 MPa. Before shale gas well fracturing construction, the whole wellbore needs to be tested at a pressure of 90 MPa or more to test the integrity of the wellbore and prepare for fracturing. The existing differential pressure opening communication device has the risk of opening during wellbore pressure testing. Once it is opened prematurely, the whole wellbore pressure test before fracturing cannot be achieved, and the integrity of the wellbore cannot be accurately evaluated, which brings many adverse factors to the later fracturing.

[0006] (2) The existing differential pressure opening communication device often fails to open under harsh well conditions such as high temperature and high pressure, and repeated pressure increase cannot open it. The tool has low success rate and insufficient reliability, and the wellbore and the formation cannot establish a circulating channel, so only coiled tubing perforation can be used, which will prolong the fracturing construction period, increase the cost, and more seriously, cause misperforation.

[0007] In order to solve the above problems, the present application provides a shale gas well completion pipe string pressure test nipple structure and use method, which solves the problems of the existing differential pressure opening type communication device, such as limited pressure test times and pressure test time, unstable communication opening under harsh well conditions. SUMMARY

[0008] The present application aims to provide a shale gas well completion pipe string pressure test nipple structure and use method, which can meet the technical requirements of shale gas wellbore rapid pressure test and first-stage communication, can perform first-stage fracturing operation after pressure test, realizes pressure test operation and communication process in succession without interruption, has good mechanical delay effect, short operation time, simple structure, high reliability, simple operation, and is economical and practical.

[0009] The present application is achieved in that a shale gas well completion pipe string pressure test nipple structure comprises a pressure test nipple body, an annular groove is arranged on the outer wall of the pressure test nipple body, a lower joint is connected to the bottom end of the pressure test nipple body, an outer sleeve is arranged on the outer side of the pressure test nipple body and the lower joint, a liquid cylinder is formed between the outer sleeve, the annular groove and the lower joint, and a piston capable of sliding up and down is arranged in the liquid cylinder; a first liquid inlet and a second liquid inlet are arranged on the side wall of the pressure test nipple body in an up-down interval, and a liquid outlet is arranged on the outer sleeve at a position corresponding to the second liquid inlet.

[0010] A guide groove structure is arranged below the second liquid inlet on the outer wall of the pressure test nipple body, the guide groove structure comprises n upward V-shaped grooves arranged in a circumferential direction, n>=3; the top end of each V-shaped groove forms an upper limit point, and the bottom end of each V-shaped groove forms a lower limit point; a sliding pin capable of moving along the guide groove structure is connected to the piston; the next upper limit point in the moving direction of the sliding pin is lower than or equal to the previous upper limit point and higher than the previous lower limit point; the next lower limit point in the moving direction of the sliding pin is lower than or equal to the previous lower limit point; and the lower limit point of the nth V-shaped groove is located at the bottom of the outer wall of the pressure test nipple body; when the sliding pin moves to the lower limit point of the nth V-shaped groove, the second liquid inlet is in communication with the liquid outlet.

[0011] In a preferred embodiment of the present application, a support ring is arranged below the piston, a first semicircular groove is arranged on the end face of the bottom end of the piston, a second semicircular groove is arranged on the top end face of the support ring, a plurality of steel balls are clamped in the first semicircular groove and the second semicircular groove, and the piston, the steel balls and the support ring form a thrust ball bearing.

[0012] In a preferred embodiment of the present application, a reset spring is arranged in the liquid cylinder between the support ring and the lower joint.

[0013] In a preferred embodiment of the present application, the piston is fixedly connected to the outer sleeve by a shear pin, which is located below the liquid outlet.

[0014] In a preferred embodiment of the present application, the second liquid inlet and the liquid outlet are in the shape of an ellipse.

[0015] In a preferred embodiment of the present application, the number of the second liquid inlets is eight, which are evenly distributed in the circumferential direction, and each of the liquid outlets is correspondingly arranged with each of the second liquid inlets.

[0016] In a preferred embodiment of the present application, the adjacent two V-shaped grooves are connected by an inclined reversing groove, and the reversing groove is arranged at an angle of 30° with the axis of the pressure testing nipple body.

[0017] In a preferred embodiment of the present application, the top end of the outer sleeve and the top end of the pressure testing nipple body are fixedly and sealingly connected by welding, the bottom end of the outer sleeve is fixedly connected with the lower joint by threads and a set screw, and the lower joint is threadedly connected with the bottom end of the pressure testing nipple body.

[0018] In a preferred embodiment of the present application, the sliding pin is threadedly connected with the piston.

[0019] In a preferred embodiment of the present application, a first outer sealing ring is arranged between the top end of the outer wall of the piston and the inner wall of the outer sleeve, a first inner sealing ring is arranged between the top end of the inner wall of the piston and the outer wall of the pressure testing nipple body, a second outer sealing ring is arranged between the outer wall of the piston below the shear pin and the inner wall of the outer sleeve, and a second inner sealing ring is arranged between the inner wall of the piston below the shear pin and the outer wall of the pressure testing nipple body.

[0020] The present application can also be achieved by a method for using the shale gas well completion string pressure testing nipple structure, which comprises the following steps: when the shale gas well completion string pressure testing nipple structure is in an initial state, the sliding pin is located at a first upper limit point, liquid is introduced into the liquid cylinder from the first liquid inlet for the first time, pressure is applied to the piston, and when the generated downward thrust is greater than the required force for the downward movement of the piston, the piston drives the sliding pin to move along the guide groove structure; the pressure testing is performed each time the sliding pin moves to a lower limit point; the sliding pin finally moves to the lower limit point of the lowest nth V-shaped groove, the second liquid inlet is communicated with the liquid outlet, and the first-stage fracturing operation is performed.

[0021] According to the above description, the shale gas well completion string pressure testing nipple structure and the method for using the same have the following beneficial effects:

[0022] The shale gas well completion pipe string pressure test nipple structure of the present application can complete one pressure test for each V-shaped groove, and multiple pressure tests for multiple V-shaped grooves, and the time for each pressure test is not limited, and the mechanical delay function is provided; the present application can meet the technical requirements of rapid pressure test and first section communication for shale gas well bore, and after the pressure test of multiple V-shaped grooves is completed, the second liquid inlet and the liquid outlet are communicated, the first section fracturing operation can be carried out, the pressure test operation and the communication process are carried out successively, without interruption, the mechanical delay effect is good, the operation time is short, the structure is simple, the reliability is high, the operation is simple, and the present application is economic and practical. BRIEF DESCRIPTION OF DRAWINGS

[0023] The following drawings are only intended to illustrate and explain the present application, and do not limit the scope of the present application.

[0024] Among them:

[0025] Figure 1 : it is the schematic diagram of the shale gas well completion pipe string pressure test nipple structure of the present application.

[0026] Figure 2 : Figure 1 the enlarged view of the middle I.

[0027] Figure 3 : it is the development drawing of the guide groove structure of the first embodiment of the present application.

[0028] Figure 4 : it is the development drawing of the guide groove structure of the second embodiment of the present application.

[0029] In the drawing:

[0030] 1, pressure test nipple body; 2, piston; 3, first outer sealing ring; 4, first inner sealing ring; 5, outer sleeve; 6, shear pin; 7, second outer sealing ring; 8, second inner sealing ring; 9, sliding pin; 10, steel ball; 11, support ring; 12, reset spring; 13, locking screw; 14, lower joint;

[0031] 101, first upper limit point; 102, first lower limit point; 103, second upper limit point; 104, second lower limit point; 105, third upper limit point; 106, third lower limit point; 107, fourth upper limit point; 108, fourth lower limit point; 109, fifth upper limit point;

[0032] 111, first liquid inlet; 112, second liquid inlet; 113, liquid outlet. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described with reference to the drawings.

[0034] The specific embodiments of the application described herein are intended to be illustrative only and are not intended to be limiting in any way. Upon reading this disclosure, those of ordinary skill in the art will appreciate various alterations, modifications, and improvements that can be made to the methods and

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting. As used in this application, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0036] As shown in Figures 1 to 4 The present application provides a shale gas well completion string test pressure nipple structure, which comprises a test pressure nipple body 1, an annular groove is arranged on the outer wall of the test pressure nipple body 1, a lower joint 14 is connected to the bottom end of the test pressure nipple body 1, an outer sleeve 5 is sleeved on the outer side of the test pressure nipple body 1 and the lower joint 14, a liquid cylinder is formed between the outer sleeve 5, the annular groove and the lower joint 14, and a piston 2 capable of sliding up and down is sleeved in the liquid cylinder; a first liquid inlet 111 and a second liquid inlet 112 are arranged on the side wall of the test pressure nipple body 1 in an up-down interval, and a liquid outlet 113 is arranged on the outer sleeve 5 at a position corresponding to the second liquid inlet 112;

[0037] The outer wall of the pressure testing nipple body 1 is provided with a guide groove structure below the second liquid inlet, the guide groove structure comprises n open upward V-shaped grooves arranged in circumferential communication, n≥3; the top end of each V-shaped groove forms an upper limit point, the bottom end of each V-shaped groove forms a lower limit point, the piston 2 is connected with a sliding pin 9 capable of moving along the guide groove structure (the sliding pin 9 can slide up and down in the V-shaped groove and is installed at the lower part of the piston 2), and the sliding pin 9 is matched with the size of the V-shaped groove; the next upper limit point in the moving direction of the sliding pin 9 is lower than or equal to the previous upper limit point and higher than the previous lower limit point, the next lower limit point in the moving direction of the sliding pin 9 is lower than or equal to the previous lower limit point, and the lower limit point of the nth V-shaped groove is located at the bottom of the outer wall of the pressure testing nipple body 1; when the sliding pin 9 moves to the lower limit point of the nth V-shaped groove, the second liquid inlet 112 is communicated with the liquid outlet 113.

[0038] The first liquid inlet 111 is higher than the piston 2, liquid flows from the first liquid inlet 111 to the liquid cylinder, and pressure acts on the piston 2; when the generated downward thrust is greater than the force required for the movement of the piston (in this embodiment, the downward thrust is greater than the shearing force of the shearing pin 6), the piston 2 drives the sliding pin 9 to move along the guide groove structure. Each time the sliding pin 9 moves to the lower limit point, pressure testing is performed. The sliding pin 9 finally moves to the lower limit point of the lowest nth V-shaped groove, the second liquid inlet 112 is communicated with the liquid outlet 113, and the first-stage fracturing construction can be performed.

[0039] In the structure of the shale gas well completion string pressure testing nipple of the present application, each V-shaped groove can complete one pressure test, and multiple V-shaped grooves can perform multiple pressure tests, each pressure test time is not limited, and the mechanical delay function is provided; the present application can meet the technical requirements of rapid pressure testing and first-stage communication of the shale gas well, after the pressure testing of multiple V-shaped grooves is completed, the second liquid inlet 112 is communicated with the liquid outlet 113, and the first-stage fracturing construction can be performed, the pressure testing operation and the communication process are sequentially performed, interruption is not required, the mechanical delay effect is good, the operation time is short, the structure is simple, the reliability is high, the operation is simple, and the present application is economic and practical.

[0040] Further, as shown in Figure 1 , Figure 2 , the lower part of the piston 2 is provided with a support ring 11, the bottom end of the piston 2 is provided with a first semicircular groove, the top end of the support ring 11 is provided with a second semicircular groove, a plurality of steel balls 10 are clamped in the first semicircular groove and the second semicircular groove, the radius of the first semicircular groove and the second semicircular groove is matched with the steel ball 10, and the piston 2, the steel ball 10 and the support ring 11 form a thrust ball bearing, so that the piston 2 can freely move and change direction in the circumferential direction.

[0041] Further, as shown in Figure 1As shown, the reset spring 12 is arranged in the liquid cylinder between the support ring 11 and the lower joint 14, the top end of the reset spring 12 is in close contact with the bottom of the support ring, and the bottom end of the reset spring 12 is limited by the lower joint 14. The support ring 11 is sleeved on the middle part of the pressure testing nipple body 1, and the reset spring 12 is sleeved on the lower part of the pressure testing nipple body 1.

[0042] Further, as shown in the drawings, Figure 1 、 Figure 2 The piston 2 can be fixedly connected to the outer sleeve 5 through the shear pin 6, and the shear pin 6 is located below the liquid outlet 113.

[0043] The shale gas well completion string pressure testing nipple structure adopts a multiple pressing mode, the opening pressure can be artificially set, and the shear pin 6 can be determined according to the opening pressure.

[0044] Further, as shown in the drawings, Figure 1 In a specific embodiment of the present application, the second liquid inlet 112 and the liquid outlet 113 are arranged in a long circular cross-section (the second liquid inlet 112 and the liquid outlet 113 are strip-shaped structures).

[0045] The number of the second liquid inlets 112 is 8, which are uniformly distributed in the circumferential direction, and each liquid outlet 113 is arranged one-to-one with each second liquid inlet 112 (the second liquid inlet 112 and the liquid outlet 113 are aligned in the radial direction and consistent), so as to minimize the phase difference with the minimum principal stress direction of the formation.

[0046] Further, in a specific embodiment, 3 groups of V-shaped grooves are arranged on the 360-degree outer circumferential surface of the lower part of the pressure testing nipple body; adjacent two V-shaped grooves are communicated through an inclined reversing groove; and the reversing groove is arranged at an angle of 30° with the axis of the pressure testing nipple body 1.

[0047] Further, the top end of the outer sleeve 5 and the top end of the pressure testing nipple body 1 are fixedly sealed by welding; the bottom end of the outer sleeve 5 is connected and fixed with the lower joint 14 through a thread and a set screw 13; and the lower joint 14 is connected with the bottom end of the pressure testing nipple body 1 through a thread.

[0048] Further, the slide pin 9 is connected with the piston 2 through a thread.

[0049] Further, as shown in the drawings, Figure 1 The first outer sealing ring 3 is arranged between the top end of the outer wall of the piston 2 and the inner wall of the outer sleeve 5, and the first inner sealing ring 4 is arranged between the top end of the inner wall of the piston 2 and the outer wall of the pressure testing nipple body 1.

[0050] The second outer sealing ring 7 is arranged between the outer wall of the piston 2 below the shear pin 6 and the inner wall of the outer sleeve 5, and the second inner sealing ring 8 is arranged between the inner wall of the piston 2 below the shear pin 6 and the outer wall of the pressure testing nipple body 1.

[0051] Further, the inner wall top end of the test nipple body 1 is provided with an inner tapered thread, and the outer wall of the lower joint 14 is provided with an outer tapered thread, and the shale gas well completion pipe string test nipple structure is connected to the shale gas well completion pipe string through the inner tapered thread and the outer tapered thread.

[0052] The present application provides a shale gas well completion pipe string test nipple structure and a use method thereof. The use method comprises the following steps: connecting the shale gas well completion pipe string test nipple structure to a shale gas well completion pipe string; in an initial state of the shale gas well completion pipe string test nipple structure, the slide pin 9 is located at a first upper limit point; in a first shale gas well completion pipe string pressure test, liquid flows from a first liquid inlet 111 to a liquid cylinder, and pressure acts on the piston 2; when the generated downward thrust is greater than the force required for the downward movement of the piston 2, the piston 2 drives the slide pin 9 to move along the guide groove structure; each time the slide pin 9 moves to a lower limit point, a pressure test is performed; the slide pin 9 finally moves to a lower limit point of an nth V-shaped groove at the lowest position, and a second liquid inlet 112 is in communication with a liquid outlet 113, so that a first-stage fracturing operation can be performed.

[0053] Embodiment one

[0054] The guide groove structure comprises four upward-opening V-shaped grooves arranged in a circumferential direction, as shown in FIG. 1. Figure 3 The four V-shaped grooves are arranged in a stepped manner in an axial direction, and the upper limit points are set as a first upper limit point 101, a second upper limit point 103, a third upper limit point 105, a fourth upper limit point 107, and a fifth upper limit point 109, and the lower limit points are set as a first lower limit point 102, a second lower limit point 104, a third lower limit point 106, and a fourth lower limit point 108, wherein the fourth lower limit point 108 is located at the lowest end. Figure 3 Each lower limit point is circumferentially rotated by 45° relative to the upper limit point in front of it (left side in the middle).

[0055] The initial state of the shale gas well completion pipe string test nipple structure is shown in FIG. 1, wherein the slide pin 9 is located at the first upper limit point 101. Figure 1 In a first shale gas well completion pipe string pressure test, liquid flows from the first liquid inlet 111 to the liquid cylinder, and pressure acts on the piston 2; when the generated downward thrust is greater than the shearing force of the shearing pin 6, the shearing pin 6 is sheared off, the piston 2 pushes the steel ball 10 and the support ring 11 downward to press the reset spring 12, the piston 2 presses the steel ball 10 to flexibly rotate in a circumferential direction along the semicircular groove, the slide pin 9 moves from the first upper limit point 101 to the first lower limit point 102 along the guide groove structure, and stops moving at this time, and the piston 2 is rotated counterclockwise by 45° in the circumferential direction. Figure 3If the pressure test is not satisfied, the piston 2 rotates 45 degrees clockwise (the direction to the right in the drawing), and the pressure test is continued to 90 MPa, and the first pressure test is completed. If the pressure test is interrupted due to unexpected factors such as pipelines and equipment, the slide pin 9 on the piston 2 moves upward under the elastic force of the reset spring 12, and is reversely moved to the second upper limit point 103. At this time, the piston 2 continues to rotate 45 degrees counterclockwise, and the second liquid inlet 112 is not connected with the liquid outlet 113. The above steps can be repeated for the second pressure test. If the pressure test meets the design requirements, the piston 2 is moved to the fourth lower limit point 108 through three times of pressure test and pressure relief, and the second liquid inlet 112 is completely connected with the liquid outlet 113, and the first-stage fracturing operation can be continued.

[0056] In this embodiment, the slide pin 9 is stepwise moved downward through four times of pressure test, and the second liquid inlet 112 is completely connected with the liquid outlet 113 through the last pressure test, and the first-stage fracturing operation can be continued.

[0057] Embodiment Two

[0058] The guide groove structure includes four V-shaped grooves which are upwardly opened and circumferentially arranged, as shown in the drawing. Figure 4 As shown in the drawing, three V-shaped grooves are axially aligned, and one V-shaped groove is located at the bottom end of the pressure test nipple body 1.

[0059] The upper limit points are set as the first upper limit point 101, the second upper limit point 103, the third upper limit point 105, the fourth upper limit point 107, and the fifth upper limit point 109, and the lower limit points are set as the first lower limit point 102, the second lower limit point 104, the third lower limit point 106, and the fourth lower limit point 108. The fourth lower limit point 108 is located at the lowermost end. Each lower limit point is circumferentially rotated by 45 degrees relative to the upper limit point in front of it (the left side in the drawing). Figure 3

[0060] The use method of this embodiment is basically the same as that of Embodiment One, and the difference is that, in this embodiment, the slide pin 9 is stepwise moved downward to the fourth lower limit point 108 through three times of circumferential transposition, and the second liquid inlet 112 is completely connected with the liquid outlet 113 through the last pressure test, and the first-stage fracturing operation can be continued.

[0061] As described above, the shale gas well completion pipe string pressure test nipple structure and use method have the following beneficial effects:

[0062] ​The V-shaped groove in the shale gas well completion pipe string test pressure nipple structure of the present application can complete one test pressure, multiple V-shaped grooves can perform multiple test pressures, each test pressure time is not limited, and the mechanical delay function is provided; the present application can meet the technical requirements of shale gas wellbore rapid pressure test and first section communication, after the test pressure of multiple V-shaped grooves is completed, the second liquid inlet and the liquid outlet are communicated, the first section fracturing operation can be performed, the test pressure operation and the communication process are sequentially performed, interruption is not needed, the mechanical delay effect is good, the operation time is short, the structure is simple, the reliability is high, the operation is simple, and the present application is economic and practical.

[0063] The above description is merely illustrative of the present application, and is not intended to limit the scope of the present application. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present application shall fall within the scope of the present application.

Claims

1. A short section structure for pressure testing of completion tubing in a shale gas well, characterized in that, The device includes a pressure testing section body, an annular groove on the outer wall of the pressure testing section body, a lower connector connected to the bottom end of the pressure testing section body, an outer sleeve fitted over the outer sides of the pressure testing section body and the lower connector, and a hydraulic cylinder formed by the outer sleeve, the annular groove and the lower connector, with a piston that can slide up and down fitted inside the hydraulic cylinder; a first liquid inlet and a second liquid inlet are provided at vertical intervals on the side wall of the pressure testing section body, and a liquid outlet is provided on the outer sleeve at a position corresponding to the second liquid inlet; A guide groove structure is provided on the outer wall of the pressure test section body below the second liquid inlet. The guide groove structure includes n V-shaped grooves with upward openings arranged circumferentially, where n≥3. The top of each V-shaped groove forms an upper limit point, and the bottom of each V-shaped groove forms a lower limit point. A sliding pin is connected to the piston and can move along the guide groove structure. The next upper limit point along the sliding pin's movement direction is set lower than or equal to the previous upper limit point and higher than the previous lower limit point. The next lower limit point along the sliding pin's movement direction is set lower than or equal to the previous lower limit point. The lower limit point of the nth V-shaped groove is located at the bottom of the outer wall of the pressure test section body. When the sliding pin moves to the lower limit point of the nth V-shaped groove, the second liquid inlet is connected to the liquid outlet.

2. The shale gas well completion tubing test section structure as described in claim 1, characterized in that, A support ring is provided below the piston. The bottom end face of the piston is provided with a first semi-circular groove, and the top end face of the support ring is provided with a second semi-circular groove. Multiple steel balls are sandwiched in the first semi-circular groove and the second semi-circular groove. The piston, the steel balls and the support ring constitute a thrust ball bearing.

3. The shale gas well completion tubing test section structure as described in claim 2, characterized in that, A return spring is installed inside the hydraulic cylinder between the support ring and the lower connector.

4. The shale gas well completion tubing test section structure as described in claim 1, characterized in that, The piston can be fixedly connected to the outer casing by a shear pin, which is located below the liquid outlet.

5. The shale gas well completion tubing test section structure as described in claim 1, characterized in that, The second inlet and the outlet have elongated oval cross-sections.

6. The shale gas well completion tubing test section structure as described in claim 5, characterized in that, There are 8 second liquid inlets, which are evenly distributed circumferentially, and each liquid outlet is respectively set to correspond one-to-one with each of the second liquid inlets.

7. The shale gas well completion tubing test section structure as described in claim 1, characterized in that, The two adjacent V-shaped grooves are connected by an inclined reversing groove; the reversing groove is set at a 30° angle to the axis of the test pressure section body.

8. The shale gas well completion tubing test section structure as described in claim 1, characterized in that, The top of the outer sleeve and the top of the pressure test section body are fixed and sealed by welding; the bottom of the outer sleeve is fixed to the lower connector by threads and set screws; the lower connector is connected to the bottom of the pressure test section body by threads.

9. The shale gas well completion tubing test section structure as described in claim 1, characterized in that, The sliding pin is connected to the piston by a thread.

10. The shale gas well completion tubing test section structure as described in claim 4, characterized in that, A first outer sealing ring is provided between the top of the outer wall of the piston and the inner wall of the outer sleeve, and a first inner sealing ring is provided between the top of the inner wall of the piston and the outer wall of the test pressure stub body; a second outer sealing ring is provided between the outer wall of the piston located below the shear pin and the inner wall of the outer sleeve, and a second inner sealing ring is provided between the inner wall of the piston located below the shear pin and the outer wall of the test pressure stub body.

11. A method of using the shale gas well completion string pressure testing sub-section structure as described in any one of claims 1 to 10, characterized in that, include: In the initial state of the shale gas well completion string pressure test section structure, the sliding pin is located at the first upper limit point. During the first shale gas well completion string pressure test, liquid flows from the first inlet into the cylinder, and the pressure acts on the piston. When the downward thrust generated is greater than the force required for the piston to move downward, the piston drives the sliding pin to move along the guide groove structure. Each time the sliding pin moves to the lower limit point, a pressure test is performed. The sliding pin eventually moves to the lower limit point of the lowest nth V-shaped groove, and the second inlet and outlet are connected to carry out the first stage of fracturing.

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