Shale oil and gas well fracturing microseism monitoring device and monitoring method

Abstract

The invention discloses a shale oil and gas well fracturing microseism monitoring device and method, and relates to the technical field of microseism monitoring. The bottom of the sleeve is in threaded sealing connection with the central tube, the bottom of the central tube is in threaded sealing connection with the microseism sensor, a cable of the microseism sensor is arranged in the central tube, the bottom of the sleeve is in threaded connection with the spacing cover, and the spacing cover is sleeved outside the microseism sensor. The device has the beneficial effects that the spacing cover and the microseismic sensor are condensed into an integrated structure by utilizing concrete, the device can be fixed in a monitoring well by arranging the slips, the concrete is injected into the sleeve, and the spacing cover and the monitoring well are condensed into an integrated structure, so that the microseismic sensor can detect real stratum vibration, and after monitoring is finished, the device can be fixed in the monitoring well. And the slip and the spacing cover are dissolved, so that the micro-seismic sensor can be lifted out and reused, and meanwhile, the device also has the functions of on-site pouring of the micro-seismic sensor and well washing after pouring.

Description

Technical Field

[0001] The present invention relates to the technical field of microseismic monitoring, and particularly to a microseismic monitoring device and method for hydraulic fracturing of shale oil and gas wells. Background Art

[0002] With the development of the shale oil and gas field, hydraulic fracturing technology has become a key means to improve oil and gas recovery. During the hydraulic fracturing process, the fracturing fluid enters the fracture from the bottom of the well. Due to continuous pressure accumulation, the fracture will eventually break, forming microseisms, which are called microseismic events. By drilling monitoring wells in or near the fractured well and deploying microseismic sensors, three-dimensional monitoring of the microseismic events generated during the fracturing process is carried out. In order to enable the microseismic sensors to truly monitor the vibration of the formation, it is necessary to inject concrete into the monitoring well so that the microseismic sensors and the formation become an integral structure. For example, the patent application with the publication number CN108957524B discloses a microseismic geophone installation device and method, and the microseismic sensors cannot be recycled. Summary of the Invention

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

[0004] The technical solution provided by the present invention is: a microseismic monitoring device for hydraulic fracturing of shale oil and gas wells, including a casing and a central pipe. The bottom pipe thread of the casing is hermetically connected to the central pipe, the bottom of the central pipe is hermetically connected to the microseismic sensor by thread, the cable of the microseismic sensor is arranged inside 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; The outside of the casing is connected to a slip by a dovetail groove guide. The number of slips is three, and the slips are evenly distributed along the circumference of the casing. The dovetail groove guide is arranged at an inclination angle. The inclination direction of the dovetail groove guide is: while the slip descends, it expands outwards. The casing is provided with a jacket above the slip. The jacket is hermetically connected to the casing by rivets. A piston is arranged between the jacket and the casing. The lower part of the piston abuts against the slip. The piston is in clearance fit with the jacket and the casing through a sealing ring. The casing is provided with a liquid inlet hole above the piston; A switch sleeve is installed in the annulus between the casing and the central pipe. The switch sleeve is a section of tubular structure. The switch sleeve is in clearance fit with the casing and the central pipe. The pipe wall of the switch sleeve is provided with a vertical annular groove from top to bottom. The outer circle of the switch sleeve is provided with an outer annular groove. The switch sleeve is provided with an outer side hole between the outer annular groove and the vertical annular groove; The pipe wall of the casing is provided with an external injection hole below the slips. The casing and the switch sleeve are axially limited by a shear pin A. The outer ring groove of the switch sleeve is located above the external injection hole. Two sealing rings are arranged on each of the upper and lower sides of the outer ring groove of the switch sleeve. Among them, the two sealing rings below the outer ring groove cover the upper and lower sides of the external injection hole. The central pipe is inlaid with a shear pin B below the switch sleeve. The shear pin B extends out of the outer side of the central pipe. When the switch sleeve falls to the position of the shear pin B, the outer ring groove communicates with the external injection hole.

[0005] The slips and the spacer are made of soluble metal.

[0006] The inner wall of the switch sleeve is provided with an inner ring groove. Two sealing rings are arranged on each of the upper and lower sides of the inner ring groove of the switch sleeve. An inner side hole is opened between the inner ring groove and the vertical ring groove of the switch sleeve. The pipe wall of the central pipe is provided with a return hole below the switch sleeve. The central pipe is inlaid with a shear pin C below the shear pin B. The shear pin C extends out of the outer side of the central pipe. When the switch sleeve falls to the position of the shear pin C, the inner ring groove communicates with the return hole.

[0007] The switch sleeve is provided with a threaded through hole at the bottom of the vertical ring groove. A check valve is hermetically connected to the threaded through hole by internal threads. The check valve is of the steel ball spring type. The steel ball is located at the lower part. The bottom of the casing is fixedly connected to a push rod by bolts. The position of the push rod corresponds to the steel ball of the check valve. An inner injection hole is opened at the bottom of the casing. The inner injection hole communicates the space below the switch sleeve and the spacer. The switch sleeve and the central pipe are connected by a flat key. The flat key is slidably connected to the central pipe and is in transitional fit connection with the switch sleeve.

[0008] A compression spring is installed at the bottom of the casing.

[0009] The check valve is filled with glycerin.

[0010] The inclined surface of the dovetail groove guide is smaller than the friction angle between the slips and the casing.

[0011] A method for monitoring hydraulic fracturing microseismicity in shale oil and gas wells, which is applied to a device for monitoring hydraulic fracturing microseismicity in shale oil and gas wells, includes the following steps: S1. Inject concrete into the inner injection hole to coagulate the spacer and the microseismic sensor into an integral structure; S2. Lower a device for monitoring hydraulic fracturing microseismicity in shale oil and gas wells to the bottom of the monitoring well. Inject clear water into the casing to build pressure. The water pressure causes the piston to descend through the liquid inlet hole. The descending piston drives the slips to expand outwards and anchor on the well wall of the monitoring well, and the device is fixed in the monitoring well; S3. Input pulsed pressure into the casing. The pulsed pressure forces the switch sleeve to descend and cut off the shear pin A. The switch sleeve descends and lands on the shear pin B. The outer ring groove communicates with the external injection hole. Inject concrete 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; S4. Input pulse pressure into the casing again. The pulse pressure causes the switch sleeve to descend and shear the shear pin B. The switch sleeve lands on the shear pin C. At this time, the inner annular groove of the switch sleeve communicates with the return hole. Inject clear water into the casing to wash the well, and the well washing water is discharged from the central pipe through the return hole. S5. If it is necessary to pour concrete between the spacer and the microseismic sensor on site, step S4 can be skipped. Input pulse pressure into the casing again. The switch sleeve descends to shear the shear pin B and the shear pin C. The switch sleeve descends, and the ejector rod pushes open the check valve. Inject concrete into the casing again. The concrete enters the spacer and condenses the spacer and the microseismic sensor into an integral structure. S6. Release the pressure in the casing. The switch sleeve rises under the action of the compression spring. The inner annular groove communicates with the return hole. Inject clear water into the casing again to wash the well. S7. After the monitoring is completed, inject acidic solution into the annulus between the casing and the monitoring well. The acidic solution dissolves the slips and the spacer, and the casing and the microseismic sensor are lifted out of the monitoring well for recycling.

[0012] The beneficial effects of the present invention are as follows: The spacer and the microseismic sensor are condensed into an integral structure by using concrete. By setting the slips, the device can be fixed in the monitoring well. Inject concrete into the casing to condense the spacer and the monitoring well into an integral structure, so that the microseismic sensor can detect the real formation vibration. After the monitoring is completed, the slips and the spacer are dissolved, so that the microseismic sensor can be lifted out and reused. At the same time, it also has the functions of on-site casting of the microseismic sensor and well washing after casting. Description of the Drawings

[0013] Att Figure 1 is the structural schematic diagram of the present invention; Att Figure 2 is the structural schematic diagram of the switch sleeve in the present invention; Att Figure 3 is Att Figure 1 the enlarged view of part A of Att Figure 4 is the structural schematic diagram of the present invention after anchoring; Att Figure 5 is the structural schematic diagram of the present invention when the outer injection hole is opened; Att Figure 6 is the structural schematic diagram of the present invention when the return hole is opened; Att Figure 7 is the structural schematic diagram of the present invention when the inner injection hole is opened.

[0014] In the figure: 1 - casing, 2 - central pipe, 3 - monitoring well, 4 - spacer cover, 5 - switch sleeve, 501 - vertical annular groove, 502 - outer annular groove, 503 - outer side hole, 504 - inner annular groove, 505 - inner side hole, 506 - threaded through hole, 6 - microseismic sensor, 7 - slip, 8 - jacket, 9 - piston, 10 - dovetail groove guide, 11 - liquid inlet hole, 12 - shear pin A, 13 - outer injection hole, 14 - return hole, 15 - shear pin B, 16 - shear pin C, 17 - ejector rod, 18 - inner injection hole, 19 - compression spring, 20 - check valve, 21 - cable, 22 - flat key. Detailed implementation mode

[0015] As Figures 1 to 7 shown, a fracturing microseismic monitoring device for a shale oil and gas well includes a casing 1 and a central pipe 2. The bottom pipe thread of the casing 1 is sealingly connected to the central pipe 2, the bottom of the central pipe 2 is threadedly and sealingly connected to the microseismic sensor 6, and 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 cover 4, and the spacer cover 4 is sleeved outside the microseismic sensor 6; The outside of the casing 1 is connected to a slip 7 through a dovetail groove guide 10. The number of slips 7 is three, and the slips 7 are evenly distributed along the circumference of the casing 1. The dovetail groove guide 10 is arranged at an inclined angle. The inclined direction of the dovetail groove guide 10 is: while the slip 7 descends, it expands outwards. The casing 1 is provided with a jacket 8 above the slip 7. The jacket 8 is sealingly connected to the casing 1 by rivets. A piston 9 is arranged between the jacket 8 and the casing 1. The lower part of the piston 9 abuts against the slip 7. The piston 9 is in clearance fit with the jacket 8 and the casing 1 through a sealing ring. The casing 1 is provided with a liquid inlet hole 11 above the piston 9; A switch sleeve 5 is installed in the annulus between the casing 1 and the central pipe 2. The switch sleeve 5 is a section of tubular structure. The switch sleeve 5 is in clearance fit with the casing 1 and the central pipe 2. A vertical annular groove 501 is opened on the pipe wall of the switch sleeve 5 from top to bottom. An outer annular groove 502 is opened on the outer circle of the switch sleeve 5. An outer side hole 503 is opened between the outer annular groove 502 and the vertical annular groove 501 of the switch sleeve 5; An outer injection hole 13 is opened on the pipe wall of the casing 1 below the slip 7. The casing 1 and the switch sleeve 5 are axially limited by a shear pin A12. The outer annular groove 502 of the switch sleeve 5 is located above the outer injection hole 13. Two sealing rings are arranged on each of the upper and lower sides of the outer annular groove 502 of the switch sleeve 5. Among them, the two sealing rings below the outer annular groove 502 cover the upper and lower sides of the outer injection hole 13. A shear pin B15 is embedded in the central pipe 2 below the switch sleeve 5. The shear pin B15 extends outside the central pipe 2. When the switch sleeve 5 falls to the position of the shear pin B15, the outer annular groove 502 is communicated with the outer injection hole 13.

[0016] The slips 7 and the spacer cover 4 are made of soluble metal.

[0017] The inner wall of the switch sleeve 5 is provided with an inner ring groove 504. The switch sleeve 5 is provided with two sealing rings on each of the upper and lower sides of the inner ring groove 504. The switch sleeve 5 is provided with an inner side hole 505 between the inner ring groove 504 and the vertical ring groove 501. A return hole 14 is opened in the pipe wall of the central pipe 2 at the lower part of the switch sleeve 5. A shear pin C16 is embedded under the shear pin B15 in the central pipe 2, and the shear pin C16 extends out of the outer side of the central pipe 2. When the switch sleeve 5 falls to the position of the shear pin C16, the inner ring groove 504 is communicated with the return hole 14.

[0018] The switch sleeve 5 is provided with a threaded through hole 506 at the bottom of the vertical ring groove 501. A one-way valve 20 is connected to the threaded through hole 506 in a threaded and sealed manner. The one-way valve 20 is of a steel ball spring type, with the steel ball located at the lower part. The bottom of the sleeve 1 is fixedly connected to a push rod 17 through a bolt. The position of the push rod 17 corresponds to the steel ball of the one-way valve 20. An inner injection hole 18 is opened at the bottom of the sleeve 1, and the inner injection hole 18 communicates the space below the switch sleeve 5 and the spacer cover 4. The switch sleeve 5 and the central pipe 2 are connected by a flat key 22. The flat key 22 is slidably connected to the central pipe 2 and is connected to the switch sleeve 5 with an interference fit. The flat key 22 is used for circumferential positioning between the switch sleeve 5 and the central pipe 2, so that the push rod 17 and the one-way valve 20 are centered.

[0019] A compression spring 19 is installed at the bottom of the sleeve 1.

[0020] The one-way valve 20 is filled with glycerin and can operate before the secondary pouring of concrete.

[0021] The inclined surface of the dovetail groove guide 10 is smaller than the friction angle between the slip joint 7 and the sleeve 1.

[0022] A method for fracturing microseismic monitoring of shale oil and gas wells, which is applied to a device for fracturing microseismic monitoring of shale oil and gas wells, includes the following steps: S1. Inject concrete into the inner injection hole 18 to condense the spacer cover 4 and the microseismic sensor 6 into an integral structure; S2. Lower a device for fracturing microseismic monitoring of shale oil and gas wells to the bottom of the monitoring well 3, and introduce clear water into the sleeve 1 to build pressure. The water pressure causes the piston 9 to descend through the liquid inlet hole 11, and the descent of the piston 9 drives the slip joint 7 to expand outward and anchor on the well wall of the monitoring well 3, and the device is fixed in the monitoring well 3; S3. Input pulsed pressure into the sleeve 1. The pulsed pressure forces the switch sleeve 5 to descend and cut off the shear pin A12. The switch sleeve 5 descends and lands on the shear pin B15. The outer ring groove 502 is communicated with the outer injection hole 13. Inject concrete into the sleeve 1, and the concrete falls between the monitoring well 3 and the spacer cover 4, so that the spacer cover 4 and the inner wall of the monitoring well 3 become an integral structure; S4. Input pulse pressure into the casing 1 again. The pulse pressure causes the switch sleeve 5 to descend and shear the shear pin B15. The switch sleeve 5 lands on the shear pin C16. At this time, the inner annular groove 504 of the switch sleeve 5 communicates with the return hole 14. Inject clear water 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 shroud 4 and the microseismic sensor 6 on site, step S4 can be skipped. Input pulse pressure into the casing 1 again. The switch sleeve 5 descends to shear the shear pin B15 and the shear pin C16. The switch sleeve 5 descends, and the ejector rod 17 pushes open the check valve 20. Inject concrete into the casing 1 again. The concrete enters the spacer shroud 4 and condenses the spacer shroud 4 and the microseismic sensor 6 into an integral structure; S6. Release the pressure in the casing 1. The switch sleeve 5 rises under the action of the compression spring 19. The inner annular groove 504 communicates with the return hole 14. Inject clear water into the casing 1 again to wash the well; S7. After the monitoring is completed, inject acidic solution into the annulus between the casing 1 and the monitoring well 3. The acidic solution dissolves the slips 7 and the spacer shroud 4, and the casing 1 and the microseismic sensor 6 are lifted out of the monitoring well 3 for recycling.

Claims

1. A shale oil and gas well fracturing microseismic monitoring device, comprising a casing (1) and a central pipe (2), characterized in that: The bottom pipe thread of the casing (1) is sealedly connected to the central pipe (2), the bottom thread of the central pipe (2) is sealedly connected to the microseismic sensor (6), the cable (21) of the microseismic sensor (6) is arranged in the central pipe (2), the bottom thread of the casing (1) is connected to the spacer cover (4), and the spacer cover (4) is sleeved on the outside of the microseismic sensor (6); The outer side of the casing (1) is connected to the slip (7) through a dovetail groove guide rail (10). The number of the slips (7) is three. The slips (7) are evenly distributed along the circumference of the casing 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 casing (1) is provided with a jacket (8) on the upper part of the slip (7). The jacket (8) and the casing (1) are sealed and connected by rivets. A piston (9) is provided between the jacket (8) and the casing (1). The lower part of the piston (9) is pressed on the slip (7). The piston (9) is fitted with the jacket (8) and the casing (1) through a sealing ring gap. The casing (1) is provided with a liquid inlet hole (11) above the piston (9). A switch sleeve (5) is installed in the annulus between the casing (1) and the center tube (2). The switch sleeve (5) is a section of tubular structure. The switch sleeve (5) is clearance-matched with the casing (1) and the center tube (2). A vertical annular groove (501) is provided on the wall of the switch sleeve (5) from top to bottom. An outer annular groove (502) is provided on the outer circle of the switch sleeve (5). An outer edge hole (503) is provided on the switch sleeve (5) between the outer annular groove (502) and the vertical annular groove (501). An outer injection hole (13) is formed on the wall of the sleeve (1) at the lower part of the slip (7); the sleeve (1) and the switch sleeve (5) are axially limited by a shear pin A (12); the outer ring groove (502) of the switch sleeve (5) is located at the upper part of the outer 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 outer injection hole (13); the center tube (2) is inlaid with a shear pin B (15) at the lower part of the switch sleeve (5); the shear pin B (15) extends out of the outer side of the center tube (2); when the switch sleeve (5) falls to the position of the shear pin B (15), the outer ring groove (502) is communicated with the outer injection hole (13).

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

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

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

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

8. A shale oil and gas well fracturing microseismic monitoring method, characterized in that: A shale oil and gas well fracturing microseismic monitoring device as claimed in any one of claims 1 to 7, comprising the following steps: S1, injecting concrete into the inner injection hole (18) to solidify the spacer cover (4) and the microseismic sensor (6) into an integrated structure; S2, a shale oil and gas well fracturing microseismic monitoring device is lowered into the bottom of the monitoring well (3), and clean water is introduced into the casing 1 to generate pressure, and the water pressure causes the piston (9) to descend through the liquid inlet hole (11), and the descent of the piston (9) drives the slips (7) to expand outward and anchor on the wall of the monitoring well (3), and the device is fixed in the monitoring well (3); S3, inputting pulse pressure into the casing (1), the pulse pressure forces 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 annular groove (502) is connected with the outer injection hole (13), concrete is injected into the casing (1), and the concrete falls between the monitoring well (3) and the spacer cover (4), so that the spacer cover (4) and the inner wall of the monitoring well (3) become an integrated structure; S4, inputting pulse pressure into the casing (1) again, the pulse pressure causes the switch sleeve (5) to descend and cut off the shear pin B (15), and 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), and 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 cast concrete between the spacer cover (4) and the microseismic sensor (6) on site, step S4 can be skipped, and pulse pressure is input into the casing (1) again. The switch cover (5) descends to shear the shear pin B (15) and the shear pin C (16). The switch cover (5) descends, and the push rod (17) pushes open the one-way valve (20). Concrete is injected into the casing (1) again, and the concrete enters the spacer cover (4), so that the spacer cover (4) and the microseismic sensor (6) are condensed into an integrated structure. S6, the pressure in the casing (1) is released, the switch sleeve (5) rises under the action of the compression spring (19), the inner ring groove (504) is connected with the return hole (14), and clean water is injected into the casing (1) again to wash the well; S7. After the monitoring is completed, an acid solution is injected into the annulus of the casing (1) and the monitoring well (3). The acid solution dissolves the slips (7) and the spacer cover (4), and the casing (1) and the microseismic sensor (6) are taken out of the monitoring well (3) for recycling.

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