A shale oil and gas well fracturing microseismic monitoring device and a monitoring method

Abstract

The application relates to a shale oil and gas well fracturing microseismic monitoring device and a monitoring method, and relates to the technical field of microseismic monitoring. A center pipe is sealed and connected with a pipe thread at the bottom of a casing, a microseismic sensor is sealed and connected with a thread at the bottom of the center pipe, a cable of the microseismic sensor is arranged in the center pipe, a spacer cover is threadedly connected with the bottom of the casing, and the spacer cover is arranged outside the microseismic sensor. The microseismic sensor is integrated with the spacer cover by using concrete, the device can be fixed in a monitoring well by arranging a slip, concrete is injected into the casing, the spacer cover is integrated with the monitoring well, the microseismic sensor can detect real stratum vibration, the slip and the spacer cover are dissolved after monitoring, the microseismic sensor can be taken out and reused, and the device has the functions of on-site pouring of the microseismic sensor and well washing after pouring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microseismic monitoring, and particularly relates to a shale oil and gas well fracturing microseismic monitoring device and a monitoring method. BACKGROUND

[0002] With the development of the shale oil and gas field, the hydraulic fracturing technology becomes a key means for improving oil and gas recovery. In the hydraulic fracturing process, the fracturing fluid enters the fracture from the well bottom. Due to continuous pressure accumulation, the fracture will eventually break, forming a microseismic. These earthquakes are called microseismic. By drilling a monitoring well in or near the fracturing well and arranging a microseismic sensor, the microseismic generated in the fracturing process can be monitored stereoscopically. In order to enable the microseismic sensor to truly monitor the vibration of the formation, it is necessary to inject concrete into the monitoring well, so that the microseismic sensor and the formation become a structural whole. For example, the patent application with the publication number CN108957524B discloses a microseismic detector installation device and a method thereof. The microseismic sensor cannot be recycled. SUMMARY

[0003] In order to solve the problem that the microseismic sensor cannot be taken out of the monitoring well during microseismic monitoring, the present application provides a shale oil and gas well fracturing microseismic monitoring device and a monitoring method.

[0004] The technical scheme provided by the present application is as follows: a shale oil and gas well fracturing microseismic monitoring device, comprising a casing and a central pipe, the bottom of the casing is threadedly and sealingly connected to the central pipe, the bottom of the central pipe is threadedly and sealingly connected to a microseismic sensor, a cable of the microseismic sensor is arranged in the central pipe, the bottom of the casing is threadedly connected to a spacer cover, and the spacer cover is sleeved outside the microseismic sensor.

[0005] The outer side of the casing is connected to a slip through dovetail groove guide rails, the number of the slips is three, the slips are uniformly distributed along the circumference of the casing, the dovetail groove guide rails are arranged at an inclined angle, the inclined direction of the dovetail groove guide rails is that the slip expands outward while descending, the casing is provided with a clamp sleeve at the upper part of the slip, the clamp sleeve is sealingly connected to the casing through rivets, a piston is arranged between the clamp sleeve and the casing, the lower part of the piston is abutted on the slip, the piston is gap-fitted between the clamp sleeve and the casing through a sealing ring, and a liquid inlet hole is formed in the casing above the piston.

[0006] A switch sleeve is installed in the annulus between the casing and the central pipe, the switch sleeve is a tubular structure, the switch sleeve is gap-fitted between the casing and the central pipe, a vertical ring groove is formed in the wall of the switch sleeve from top to bottom, an outer ring groove is formed on the outer circle of the switch sleeve, and an outer edge hole is formed between the outer ring groove and the vertical ring groove of the switch sleeve.

[0007] The sleeve wall has an external injection hole at the lower part of the slip. The sleeve and the switch sleeve are axially limited by shear pin A. The outer ring groove of the switch sleeve is located above the external injection hole. The switch sleeve is provided with two sealing rings on the upper and lower sides of the outer ring groove. Among them, the two sealing rings at the lower part of the outer ring groove cover the upper and lower sides of the external injection hole. The central tube is embedded with shear pin B at the lower part of the switch sleeve. Shear pin B extends out of the outer side of the central tube. When the switch sleeve falls to the position of shear pin B, the outer ring groove communicates with the external injection hole.

[0008] The clapper and spacer are made of soluble metal.

[0009] The inner wall of the switch sleeve has an inner ring groove. Two sealing rings are set on the upper and lower sides of the inner ring groove. The switch sleeve has an inner edge hole between the inner ring groove and the vertical ring groove. The wall of the central tube has a return hole at the lower part of the switch sleeve. The central tube has a shear pin C embedded below the shear pin B. The shear pin C extends out of the outside of the central tube. When the switch sleeve falls to the position of the shear pin C, the inner ring groove communicates with the return hole.

[0010] The switch sleeve has a threaded through hole at the bottom of the vertical annular groove. The threaded through hole is internally threaded to seal and connect to a one-way valve. The one-way valve is a steel ball spring type, with the steel ball located at the bottom. The bottom of the sleeve is fixedly connected to a push rod by bolts. The position of the push rod corresponds to the steel ball of the one-way valve. The bottom of the sleeve has an internal injection hole that connects the lower space of the switch sleeve and the spacer cover. The switch sleeve and the central tube are connected by a flat key. The flat key is slidably connected to the central tube and transitionally connected to the switch sleeve.

[0011] A compression spring is installed at the bottom of the sleeve.

[0012] The one-way valve is filled with glycerin.

[0013] The inclination surface of the dovetail groove guide rail is smaller than the friction angle between the slip and the sleeve.

[0014] A microseismic monitoring method for fracturing shale oil and gas wells, applied to a microseismic monitoring device for fracturing shale oil and gas wells, includes the following steps:

[0015] S1. Inject concrete into the inlet hole to solidify the spacer and microseismic sensor into a single structure.

[0016] S2. A microseismic monitoring device for fracturing shale oil and gas wells is lowered to the bottom of the monitoring well. Clean water is introduced into the casing to pressurize it. The water pressure causes the piston to descend through the inlet hole. The descending piston drives the slips to expand outward and anchor them to the well wall of the monitoring well. The device is then fixed inside the monitoring well.

[0017] S3. Input pulse pressure into the casing. The pulse pressure causes the switch sleeve to descend and cut off the shear pin A. The switch sleeve descends and falls on the shear pin B. The outer ring groove is connected to the outer injection hole. Concrete is injected into the casing. The concrete falls between the monitoring well and the spacer, making the spacer and the inner wall of the monitoring well an integral structure.

[0018] S4. Input pulse pressure into the casing again. The pulse pressure causes the switch sleeve to descend and cut the shear pin B. The switch sleeve falls on the shear pin C. At this time, the inner annular groove of the switch sleeve is connected to the return hole. Inject clean water into the casing to wash the well. The well washing water is discharged from the central pipe through the return hole.

[0019] S5. If it is necessary to pour concrete between the spacer and the microseismic sensor on site, step S4 can be skipped. Pulse pressure is input into the casing again. The switch sleeve descends and cuts the shear pins B and C. The switch sleeve descends, the top rod opens the one-way valve, and concrete is injected into the casing again. The concrete enters the spacer and solidifies the spacer and the microseismic sensor into a single structure.

[0020] S6. Depressurization inside the casing occurs, and the switch sleeve rises under the action of the compression spring. The inner annular groove connects with the return hole, and clean water is injected into the casing again to wash the well.

[0021] S7. After monitoring is completed, an acidic solution is injected into the annulus of the casing and monitoring well. The acidic solution dissolves the slips and spacer, allowing the casing and microseismic sensor to be removed from the monitoring well for recycling.

[0022] The beneficial effects of this invention are as follows: the spacer cover and the microseismic sensor are integrated into a single structure using concrete. By setting the slips, the device can be fixed inside the monitoring well. Concrete is injected into the casing to integrate the spacer cover and the monitoring well into a single structure, thereby enabling the microseismic sensor to detect real ground vibrations. After monitoring, the slips and spacer cover dissolve, allowing the microseismic sensor to be removed and reused. It also has the functions of on-site casting of the microseismic sensor and well washing after casting. Attached Figure Description

[0023] Appendix Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Appendix Figure 2 This is a schematic diagram of the switch sleeve in this invention;

[0025] Appendix Figure 3 It is attached Figure 1 Enlarged view of point A;

[0026] Appendix Figure 4 This is a schematic diagram of the structure after anchoring according to the present invention;

[0027] Appendix Figure 5This is a schematic diagram of the structure when the external injection hole of the present invention is open;

[0028] Appendix Figure 6 This is a schematic diagram of the structure with the reflux hole open in this invention;

[0029] Appendix Figure 7 This is a schematic diagram of the structure with the internal injection hole open in this invention.

[0030] In the diagram: 1-Casing, 2-Central tube, 3-Monitoring well, 4-Spacer cover, 5-Switch sleeve, 501-Vertical annular groove, 502-Outer annular groove, 503-Outer edge hole, 504-Inner annular groove, 505-Inner edge hole, 506-Threaded through hole, 6-Micro seismic sensor, 7-Slipper, 8-Jacket, 9-Piston, 10-Dovetail groove guide rail, 11-Inlet hole, 12-Shear pin A, 13-External injection hole, 14-Return hole, 15-Shear pin B, 16-Shear pin C, 17-Top rod, 18-Internal injection hole, 19-Compression spring, 20-One-way valve, 21-Cable, 22-Flat key. Detailed Implementation

[0031] like Figures 1-7 As shown, a microseismic monitoring device for fracturing shale oil and gas wells includes a casing 1 and a central pipe 2. The bottom of the casing 1 is threadedly connected to the central pipe 2, and the bottom of the central pipe 2 is threadedly connected to a microseismic sensor 6. The cable 21 of the microseismic sensor 6 is arranged inside the central pipe 2. The bottom of the casing 1 is threadedly connected to a spacer 4, and the spacer 4 is fitted over the outside of the microseismic sensor 6.

[0032] The outer side of the sleeve 1 is connected to the slip 7 via the dovetail groove guide rail 10. There are three slips 7, which are evenly distributed around the circumference of the sleeve 1. The dovetail groove guide rail 10 is arranged at an inclined angle. The inclined direction of the dovetail groove guide rail 10 is: the slip 7 descends and expands outward. The sleeve 1 is provided with a jacket 8 on the upper part of the slip 7. The jacket 8 is connected to the sleeve 1 by a rivet seal. A piston 9 is provided between the jacket 8 and the sleeve 1. The lower part of the piston 9 rests on the slip 7. The piston 9 is fitted with the jacket 8 and the sleeve 1 by a sealing ring clearance. The sleeve 1 has a liquid inlet hole 11 above the piston 9.

[0033] A switch sleeve 5 is installed in the annular space between the sleeve 1 and the central tube 2. The switch sleeve 5 is a tubular structure. The switch sleeve 5 is clearance-fitted with the sleeve 1 and the central tube 2. The tube wall of the switch sleeve 5 has a vertical annular groove 501 from top to bottom. The outer circle of the switch sleeve 5 has an outer annular groove 502. The switch sleeve 5 has an outer hole 503 between the outer annular groove 502 and the vertical annular groove 501.

[0034] The sleeve 1 has an external injection hole 13 at the lower part of the slip 7. The sleeve 1 and the switch sleeve 5 are axially limited by the shear pin A12. The outer ring groove 502 of the switch sleeve 5 is located above the external injection hole 13. The switch sleeve 5 has two sealing rings on the upper and lower sides of the outer ring groove 502. The two sealing rings at the lower part of the outer ring groove 502 cover the upper and lower sides of the external injection hole 13. The central tube 2 has a shear pin B15 embedded in the lower part of the switch sleeve 5. The shear pin B15 extends out of the outside of the central tube 2. When the switch sleeve 5 falls to the position of the shear pin B15, the outer ring groove 502 communicates with the external injection hole 13.

[0035] The 7-piece set and the 4-piece spacer are made of soluble metal.

[0036] The inner wall of the switch sleeve 5 has an inner ring groove 504. Two sealing rings are provided on the upper and lower sides of the inner ring groove 504. The switch sleeve 5 has an inner edge hole 505 between the inner ring groove 504 and the vertical ring groove 501. The wall of the central tube 2 has a return hole 14 at the lower part of the switch sleeve 5. The central tube 2 has a shear pin C16 embedded below the shear pin B15. The shear pin C16 extends out of the outside of the central tube 2. When the switch sleeve 5 falls to the position of the shear pin C16, the inner ring groove 504 communicates with the return hole 14.

[0037] The switch sleeve 5 has a threaded through hole 506 at the bottom of the vertical annular groove 501. The threaded through hole 506 is internally threaded and sealed to a one-way valve 20. The one-way valve 20 is a steel ball spring type, with the steel ball located at the bottom. The bottom of the sleeve 1 is fixedly connected to the push rod 17 by bolts. The position of the push rod 17 corresponds to the steel ball of the one-way valve 20. The bottom of the sleeve 1 has an internal injection hole 18, which connects the lower space of the switch sleeve 5 and the spacer 4. The switch sleeve 5 and the central tube 2 are connected by a flat key 22. The flat key 22 is slidably connected to the central tube 2 and is transitionally connected to the switch sleeve 5. The flat key 22 is used for circumferential limiting between the switch sleeve 5 and the central tube 2, so that the push rod 17 and the one-way valve 20 are aligned.

[0038] A compression spring 19 is installed at the bottom of sleeve 1.

[0039] The one-way valve 20 is filled with glycerin and can be activated before the second concrete pour.

[0040] The inclined surface of the dovetail groove guide rail 10 is smaller than the friction angle between the slip 7 and the sleeve 1.

[0041] A microseismic monitoring method for fracturing shale oil and gas wells, applied to a microseismic monitoring device for fracturing shale oil and gas wells, includes the following steps:

[0042] S1. Inject concrete into the inward injection hole 18 to solidify the spacer 4 and the microseismic sensor 6 into a single structure.

[0043] S2. A shale oil and gas well fracturing microseismic monitoring device is lowered into the bottom of the monitoring well 3. Clean water is introduced into the casing 1 to pressurize it. The water pressure causes the piston 9 to descend through the inlet hole 11. The descending piston 9 drives the slip 7 to expand outward and anchor to the well wall of the monitoring well 3. The device is then fixed inside the monitoring well 3.

[0044] S3. Input pulse pressure into casing 1. The pulse pressure causes switch sleeve 5 to descend and cut shear pin A12. Switch sleeve 5 descends and falls on shear pin B15. Outer ring groove 502 is connected to external injection hole 13. Concrete is injected into casing 1. The concrete falls between monitoring well 3 and spacer 4, making spacer 4 and the inner wall of monitoring well 3 an integral structure.

[0045] S4. Input pulse pressure into casing 1 again. The pulse pressure causes switch sleeve 5 to descend and cut shear pin B15. Switch sleeve 5 falls on shear pin C16. At this time, the inner ring groove 504 of switch sleeve 5 is connected to return hole 14. Clean water is injected into casing 1 to wash the well. The well washing water is discharged from central pipe 2 through return hole 14.

[0046] S5. If it is necessary to pour concrete between the spacer 4 and the microseismic sensor 6 on site, step S4 can be skipped. Pulse pressure is input into the sleeve 1 again. The switch sleeve 5 descends and cuts the shear pins B15 and C16. The switch sleeve 5 descends and the top rod 17 opens the one-way valve 20, injecting concrete into the sleeve 1 again. The concrete enters the spacer 4 and solidifies the spacer 4 and the microseismic sensor 6 into an integrated structure.

[0047] S6. Depressurize the casing 1. The switch sleeve 5 rises under the action of the compression spring 19. The inner annular groove 504 connects with the return hole 14, and clean water is injected into the casing 1 again to wash the well.

[0048] S7. After monitoring is completed, an acidic solution is injected into the annulus of casing 1 and monitoring well 3. The acidic solution dissolves the slip 7 and spacer 4, and casing 1 and microseismic sensor 6 are removed from monitoring well 3 for recycling.

Claims

1. A microseismic monitoring device for fracturing shale oil and gas wells, comprising a casing (1) and a central tube (2), characterized in that: The bottom thread of the sleeve (1) is connected to the central tube (2), the bottom thread of the central tube (2) is connected to the micro seismic sensor (6), the cable (21) of the micro seismic sensor (6) is arranged inside the central tube (2), the bottom thread of the sleeve (1) is connected to the spacer (4), and the spacer (4) is fitted outside the micro seismic sensor (6). The outer side of the sleeve (1) is connected to the slip (7) through the dovetail groove guide rail (10). There are three slips (7). The slips (7) are evenly distributed around the circumference of the sleeve 1. The dovetail groove guide rail (10) is arranged at an inclined angle. The inclined direction of the dovetail groove guide rail (10) is: the slip (7) expands outward while descending. The sleeve (1) is provided with a jacket (8) on the upper part of the slip (7). The jacket (8) is sealed to the sleeve (1) by rivets. A piston (9) is provided between the jacket (8) and the sleeve (1). The lower part of the piston (9) rests on the slip (7). The piston (9) is fitted with the jacket (8) and the sleeve (1) by a sealing ring. The sleeve (1) has an inlet hole (11) above the piston (9). A switch sleeve (5) is installed in the annular space between the sleeve (1) and the central tube (2). The switch sleeve (5) is a tubular structure. The switch sleeve (5) is clearance-fitted with the sleeve (1) and the central tube (2). The tube wall of the switch sleeve (5) has a vertical annular groove (501) from top to bottom. The outer circle of the switch sleeve (5) has an outer annular groove (502). The switch sleeve (5) has an outer hole (503) between the outer annular groove (502) and the vertical annular groove (501). The sleeve (1) has an external injection hole (13) at the lower part of the slip (7) on the tube wall. The sleeve (1) and the switch sleeve (5) are axially limited by shear pin A (12). The outer ring groove (502) of the switch sleeve (5) is located above the external injection hole (13). The switch sleeve (5) is provided with two sealing rings on the upper and lower sides of the outer ring groove (502). The two sealing rings at the lower part of the outer ring groove (502) cover the upper and lower sides of the external injection hole (13). The central tube (2) is inlaid with shear pin B (15) at the lower part of the switch sleeve (5). Shear pin B (15) extends out of the outside of the central tube (2). When the switch sleeve (5) falls to the position of shear pin B (15), the outer ring groove (502) communicates with the external injection hole (13).

2. The shale oil and gas well fracturing microseismic monitoring device according to claim 1, characterized in that: The kava (7) and spacer (4) are made of soluble metal.

3. The shale oil and gas well fracturing microseismic monitoring device according to claim 1, characterized in that: The inner wall of the switch sleeve (5) has an inner ring groove (504). The switch sleeve (5) has two sealing rings on the upper and lower sides of the inner ring groove (504). The switch sleeve (5) has an inner side hole (505) between the inner ring groove (504) and the vertical ring groove (501). The wall of the central tube (2) has a return hole (14) at the lower part of the switch sleeve (5). The central tube (2) has a shear pin C (16) embedded at the lower part of the shear pin B (15). The shear pin C (16) extends out of the outside of the central tube (2). When the switch sleeve (5) falls to the position of the shear pin C (16), the inner ring groove (504) communicates with the return hole (14).

4. The shale oil and gas well fracturing microseismic monitoring device according to claim 1, characterized in that: The switch sleeve (5) has a threaded through hole (506) at the bottom of the vertical annular groove (501). The threaded through hole (506) is internally threaded and sealed to a one-way valve (20). The one-way valve (20) is a steel ball spring type, with the steel ball located at the bottom. The bottom of the sleeve (1) is fixedly connected to the top rod (17) by bolts. The position of the top rod (17) corresponds to the steel ball of the one-way valve (20). The bottom of the sleeve (1) has an internal injection hole (18). The internal injection hole (18) connects the lower space of the switch sleeve (5) and the spacer (4). The switch sleeve (5) and the central tube (2) are connected by a flat key (22). The flat key (22) is slidably connected to the central tube (2) and is transitionally connected to the switch sleeve (5).

5. The shale oil and gas well fracturing microseismic monitoring device according to claim 1, characterized in that: A compression spring (19) is installed at the bottom of the sleeve (1).

6. The shale oil and gas well fracturing microseismic monitoring device according to claim 4, characterized in that: The one-way valve (20) is filled with glycerin.

7. The shale oil and gas well fracturing microseismic monitoring device and method according to claim 1, characterized in that: The inclined surface of the dovetail groove guide rail (10) is smaller than the friction angle of the slip (7) and the sleeve (1).

8. A method for monitoring fracturing in shale oil and gas wells using microseismic monitoring, characterized in that, The microseismic monitoring device for fracturing shale oil and gas wells as described in any one of claims 1 to 7 comprises the following steps: S1. Inject concrete into the inlet injection hole (18) to solidify the spacer cover (4) and the microseismic sensor (6) into a single structure; S2. A microseismic monitoring device for fracturing shale oil and gas wells is lowered into the bottom of the monitoring well (3). Clean water is introduced into the casing 1 to pressurize it. The water pressure causes the piston (9) to descend through the inlet hole (11). The piston (9) descends and drives the slip (7) to expand outward and anchor on the well wall of the monitoring well (3). The device is fixed in the monitoring well (3). S3. Input pulse pressure into the casing (1). The pulse pressure causes the switch sleeve (5) to descend and cut the shear pin A (12). The switch sleeve (5) descends and falls on the shear pin B (15). The outer ring groove (502) is connected to the outer injection hole (13). Concrete is injected into the casing (1). The concrete falls between the monitoring well (3) and the spacer (4), making the spacer (4) and the inner wall of the monitoring well (3) an integral structure. S4. Input pulse pressure into the casing (1) again. The pulse pressure causes the switch sleeve (5) to descend and cut the shear pin B (15). The switch sleeve (5) falls on the shear pin C (16). At this time, the inner ring groove (504) of the switch sleeve (5) is connected to the return hole (14). Clean water is injected into the casing (1) to wash the well. The well washing water is discharged from the central pipe (2) through the return hole (14). S5. If it is necessary to pour concrete between the spacer cover (4) and the microseismic sensor (6) on site, step S4 can be skipped. Pulse pressure is input into the sleeve (1) again. The switch sleeve (5) descends and cuts the shear pins B (15) and C (16). The switch sleeve (5) descends and the top rod (17) opens the one-way valve (20). Concrete is injected into the sleeve (1) again. The concrete enters the spacer cover (4) and solidifies the spacer cover (4) and the microseismic sensor (6) into an integrated structure. S6. Depressurize the casing (1), and the switch sleeve (5) rises under the action of the compression spring (19). The inner ring groove (504) connects with the return hole (14), and clean water is injected into the casing (1) again to wash the well. S7. After monitoring is completed, an acidic solution is injected into the annulus of the casing (1) and the monitoring well (3). The acidic solution dissolves the slips (7) and the spacer (4), and the casing (1) and the microseismic sensor (6) are removed from the monitoring well (3) for recycling.

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