Sand control packer and separate layer mining and grouting process

Abstract

The present application belongs to the technical field of geothermal well, and particularly relates to a sand-preventing packer and a layered production and injection process. The sand-preventing packer comprises a center pipe, a pack-off assembly arranged on the outer wall of the center pipe, and a sand washing assembly arranged on the center pipe above the pack-off assembly. The pack-off assembly is arranged to be capable of being radially expanded in response to the pressure in the center pipe to complete pack-off. The sand washing assembly is arranged to be capable of being opened in response to the pressure in the center pipe, so that the fluid in the center pipe flows to the outside of the center pipe through the sand washing assembly, and the sand and gravel above the pack-off assembly outside the center pipe is brought to the wellhead. The present application can clean the sand and gravel when the packer is buried by the sand and gravel, thereby facilitating the unsealing of the packer.

Description

Technical Field

[0001] This invention belongs to the field of geothermal well technology, specifically relating to a sand-proof packer and a stratified extraction and irrigation process. Background Technology

[0002] Geothermal resources, as a clean energy source, can be used for hot springs, heating, power generation, irrigation, and other purposes. Currently, countries around the world are vigorously developing geothermal resources.

[0003] Currently, geothermal wells generally employ a general extraction and injection method, resulting in low utilization of geothermal resources and a high risk of groundwater pollution. Geothermal wells also suffer from severe sand production; the current sand control methods for geothermal wells are mainly chemical and mechanical.

[0004] In practical applications, chemical sand control has proven to be ineffective.

[0005] When using mechanical sand control, sand or solid precipitation in the formation above the packer can accumulate, directly burying the tubing and packer. This increases resistance during packer release, making release impossible. If the well casing uses a differential pressure packer, the small gap between the packer sleeve and the wellbore, combined with the bridging effect of large sand particles, can also cause sand burial of the tubing and packer. Once the tubing is buried, the increased friction during tubing tripping prevents packer release and well workover.

[0006] Chinese patent document CN211008559U discloses a drillable well-washing packer. During well washing, pressure is applied to the annulus, and the fluid in the annulus enters the annular space between the rubber sleeve seat and the upper outer sleeve through the gap between the T-shaped sealing ring cap and the J-shaped sealing ring. This pushes the well-washing sliding sleeve upward, opening the well-washing fluid inlet on the central tube wall. At this time, the well-washing fluid in the annulus above the sealing sleeve reaches the annulus below the sealing sleeve through the well-washing channel and the guide hole on the lower pressure ring of the rubber sleeve, thus performing the well-washing operation. When performing sand flushing in geothermal wells, it is necessary to flush away the sediment on the top of the packer. If pressure is applied to the annulus for well washing, the well-washing fluid will directly enter the upper geothermal reservoir, failing to flush away the sediment on the top of the packer. Therefore, it is necessary to design a sand-resistant and easily unsealed packer to provide a tool support for realizing stratified production and injection of geothermal wells.

[0007] Furthermore, regarding the stratified extraction and injection technology of geothermal wells, Chinese patent document CN114909108A ​​discloses a geothermal development system and construction method, including a geothermal system composed of a geothermal well, an inner pipe, and a sealing assembly. The inner pipe is installed in the geothermal well, and an annular channel is formed between the outer wall of the inner pipe and the geothermal well. The sealing assembly is installed in the annular channel, dividing the annular channel into an upper section and a lower section. The upper and lower sections are respectively connected to different water-conducting layers, and the lower section is connected to the inner pipe. The upper section of the inner pipe is used to connect one of the heating pipeline and the reinjection pipeline, and the upper section of the annular channel is used to connect the other of the heating pipeline and the reinjection pipeline, thereby realizing the extraction and injection from the same well. Summary of the Invention

[0008] In view of the technical problems mentioned above, the present invention aims to provide a sand-proof packer that enables the packer to be cleared of sand and gravel when it is buried, thereby facilitating the release of the packer.

[0009] The present invention also proposes a layered extraction and irrigation process, which uses the sand-blocking packer provided by the present invention to separate the deep geothermal water layer and the shallow geothermal water layer, enabling simultaneous extraction from different layers.

[0010] According to the present invention, a sand-proof packer is provided, comprising:

[0011] Central tube;

[0012] A sealing assembly is disposed on the outer wall of the central tube and is configured to expand radially in response to pressure within the central tube to complete the sealing.

[0013] A sand flushing assembly is disposed on the central tube, located above the packer assembly. The sand flushing assembly is configured to open in response to the pressure inside the central tube, allowing fluid inside the central tube to flow through the sand flushing assembly to the outside of the central tube, and carrying the sand and gravel above the packer assembly outside the central tube to the wellhead.

[0014] In a preferred embodiment, the sand flushing assembly includes:

[0015] The upper sleeve has its upper end fixedly disposed on the outer wall of the central tube, and a sand flushing port is provided on the upper sleeve.

[0016] A sand control valve is located between the upper sleeve and the central tube. A pressure transmission hole is provided on the wall of the central tube. The sand control valve is configured to move axially in response to pressure from the pressure transmission hole, thereby opening the sand flushing port and connecting the pressure transmission hole with the sand flushing port.

[0017] In a preferred embodiment, the sand valve is fixedly connected to the upper sleeve by sand-proof shear pins.

[0018] In a preferred embodiment, a spring is provided between the upper axial end of the sand valve and the upper sleeve.

[0019] In a preferred embodiment, the lower end of the upper sleeve contacts the upper end of the sealing assembly.

[0020] In a preferred embodiment, the sealing assembly includes a rubber sleeve assembly and a slip assembly disposed sequentially from top to bottom on the outer wall of the central tube.

[0021] The slip assembly is configured to expand radially in response to pressure in the central tube, thereby securing the central tube to the well casing.

[0022] The rubber sleeve assembly is configured to expand radially in response to the pressure of the central tube, thereby sealing the annulus between the central tube and the well casing.

[0023] In a preferred embodiment, the glue cartridge assembly includes:

[0024] A rubber sleeve seat is fixedly installed on the outer wall of the central tube;

[0025] The rubber sleeve cap is fixed on the central tube by the second setting screw;

[0026] The middle rubber cylinder is disposed between the rubber cylinder seat and the rubber cylinder pressure cap;

[0027] End tubes are disposed at both ends of the middle rubber tube;

[0028] The upper piston is fixed at the lower end of the rubber tube cap by a first setting shear pin. A pressure hole is provided on the tube wall of the central tube. The upper piston can move upward in response to the pressure from the pressure hole, pushing the rubber tube cap to squeeze the end rubber tube and the middle rubber tube, causing the end rubber tube and the middle rubber tube to expand radially.

[0029] In a preferred embodiment, the slip assembly includes a lower piston fixed to the outer wall of the central tube by a first setting shear pin. An upper cone and a lower cone are also provided on the outer wall of the central tube. A cylindrical slip is provided on the outer wall of the upper cone and the lower cone. The lower piston can move downward in response to pressure from the pressure hole, thereby pushing the upper cone to move downward relative to the lower cone, and thus causing the cylindrical slip to expand radially.

[0030] In a preferred embodiment, an elastic claw sleeve is fixedly provided at the lower end of the central tube, and a lower connecting sleeve is provided at the lower end of the lower cone. The lower connecting sleeve is axially fixed to the elastic claw sleeve, and the elastic claw sleeve is configured to be able to release the axial fixation with the lower connecting sleeve under the action of the unsealing tool.

[0031] According to the present invention, a layered extraction and irrigation process is also provided, in which a sand-blocking packer provided according to the present invention is used to separate the shallow geothermal layer from the deep geothermal layer, and the shallow geothermal layer and the deep geothermal layer are extracted respectively.

[0032] According to the present invention, a layered extraction and injection process is also provided, in which a sand-blocking packer provided according to the present invention is used to separate the shallow geothermal layer from the deep geothermal layer, the deep geothermal layer is extracted, and the used geothermal water is reinjected into the shallow geothermal layer.

[0033] According to the present invention, a stratified extraction and irrigation process is also provided, in which a sand-blocking packer provided according to the present invention is used to separate the shallow geothermal layer from the deep geothermal layer, the used deep geothermal water is reinjected into the deep geothermal layer, and the used shallow geothermal water is reinjected into the shallow geothermal layer.

[0034] Compared with the prior art, this application has at least the following advantages.

[0035] Before the sand packer of the present invention is unsealed, it first pressurizes the inside of the central tube and transmits the pressure to the sand valve through the pressure transmission hole, causing the sand valve to move axially and thus opening the sand flushing port. After the sand flushing port is opened, it is connected to the pressure transmission hole. At this time, the fluid in the central tube can flush the sand and gravel accumulated outside the packer through the pressure transmission hole and the sand flushing port, and send these sand and gravel to the wellhead, thereby facilitating the unsealing of the packer.

[0036] The layered extraction and irrigation process uses the sand-blocking packer provided by this invention to separate the deep and shallow geothermal layers, enabling simultaneous extraction from different layers. Attached Figure Description

[0037] The present invention will now be described with reference to the accompanying drawings.

[0038] Figure 1 A schematic diagram of one embodiment of the sand-proof packer according to the present invention is shown;

[0039] Figure 2 A schematic diagram showing an embodiment of an unsealing tool for a sand-proof packer according to the present invention is shown;

[0040] Figure 2a and Figure 2b A schematic diagram showing the unsealing tool according to the invention passing through the elastic claw support sleeve of the sand-proof packer is provided. Figure 2a and Figure 2b This is only used to simply illustrate the positional relationship between the unsealing tool and the elastic claw support sleeve;

[0041] Figure 3 A schematic diagram of one embodiment of the stratified irrigation process according to the present invention is shown.

[0042] In the picture:

[0043] 1. Upper connector; 70. Sand flushing assembly; 71. Sand flushing port; 72. Pressure transmission hole; 2. Upper sleeve; 3. Sand prevention valve; 4. Spring; 5. Sand prevention shear pin; 60. Sealing assembly; 61. Rubber sleeve assembly; 62. Slip assembly; 63. Pressure hole; 6. Rubber sleeve seat; 7. Anti-protrusion ring; 8. End rubber sleeve; 9. Middle rubber sleeve; 10. Central tube; 11. Second setting shear pin; 12. Rubber sleeve pressure cap; 13. Expansion ring; 14. First setting shear pin; 15. Upper piston; 16. Double-sided snap ring; 17. Lower piston; 18. Upper cone; 19. Cylindrical slip; 20. Lower cone; 21. Lower connecting sleeve; 22. Elastic 23. Claw sleeve; 24. Elastic claw support sleeve; 25. First unsealing shear pin; 26. Lower connector; 27. Unsealing upper connector; 28. Lower center tube; 29. ​​Claw limiting sleeve; 20. Shoulder; 30. Return spring; 31. Unsealing elastic claw; 32. Unsealing support ring; 33. Support ring step; 34. Guide head; 35. Upper part of water intake four-way; 36. Lower part of water intake four-way; 37. Water pump; 38. Oil sleeve annulus; 39. Central oil tube; 40. Shallow perforation casing; 41. Shallow geothermal water layer; 42. Sand control packer; 43. Deep sand control screen pipe; 44. Deep geothermal water layer; 200. Unsealing tool.

[0044] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0045] The invention will now be described with reference to the accompanying drawings.

[0046] It should be noted that in this application, the direction near the wellhead after the well is entered according to the present invention is described as "up" or a similar term, that is... Figure 1 Above; while the direction away from the wellhead is described as "below" or similar, that is... Figure 1 Below.

[0047] Example 1:

[0048] Figure 1 The structure of the sand-proof packer 40 according to the present invention is shown. For example... Figure 1 As shown, the sand-proof packer 40 includes a central tube 10, a packer assembly 60, and a sand-flushing assembly 70.

[0049] The sealing assembly 60 is disposed on the outer wall of the central tube 10, and the central axis of the sealing assembly 60 coincides with the central axis of the central tube 10. The sealing assembly 60 is configured to respond to radial expansion in response to pressure within the central tube 10 to complete the sealing.

[0050] The sand flushing assembly 70 is mounted on the center tube 10, above the packer assembly 60, and the central axis of the sand flushing assembly 70 coincides with the central axis of the center tube 10. The sand flushing assembly 70 is configured to open in response to the pressure inside the center tube 10, allowing fluid inside the center tube 10 to flow through the sand flushing assembly 70 to the outside of the center tube 10, carrying the sand and gravel above the packer assembly 60 outside the center tube 10 to the wellhead.

[0051] Specifically, during operation, the sand packer 40 enters the well casing (not shown in the figure) below. When sealing is required, a ball is thrown into the central tube 10 to pressurize it. Then, the sealing assembly 60 expands radially in response to the pressure inside the central tube 10, thereby sealing the annulus between the central tube 10 and the well casing.

[0052] Due to severe sand production in geothermal wells, the annulus between the central tube 10 and the well casing is frequently buried by gravel, increasing the frictional resistance between the packer and the well casing during unsealing and making unsealing difficult. When unsealing is required using the sand-proof packer 40 provided by this invention, pressure is created by throwing balls into the central tube 10. Then, the sand flushing assembly 70 opens in response to the pressure inside the central tube 10, allowing the fluid inside the central tube 10 to flow to the outside of the central tube 10 through the sand flushing assembly 70. That is, fluid with a certain pressure enters the annulus between the central tube 10 and the well casing. With the sand-proof packer 40 blocking the flow, the fluid can only carry the accumulated gravel towards the wellhead, thereby bringing the gravel above the packer assembly 60 to the wellhead, facilitating movement during unsealing.

[0053] It is easy to understand that the structure inside the central tube 10 used for pitching pressure is existing technology and will not be described in detail here.

[0054] According to the present invention, the sand flushing assembly 70 includes an upper sleeve 2 and a sand control valve 3.

[0055] The upper end of the upper sleeve 2 has a smaller diameter than the lower middle part, thus fixing the upper end of the upper sleeve 2 to the outer wall of the central tube 10. There is a gap between the lower middle part of the upper sleeve 2 and the central tube 10, and a sand flushing port 71 is provided on the upper sleeve 2, which connects the inner and outer sides of the upper sleeve 2. The lower end of the upper sleeve 2 abuts against the upper end of the sand flushing assembly 70.

[0056] The sand control valve 3 is located between the upper sleeve 2 and the central tube 10, that is, between the lower middle part of the upper sleeve 2 and the central tube 10. The sand control valve 3 is fixedly connected to the upper sleeve 2 by the sand control shear pin 5, at which time the sand control valve 3 closes the sand flushing port 71. A pressure transmission hole 72 is provided on the pipe wall of the central tube 10. The sand control valve 3 is configured to move axially in response to the pressure from the pressure transmission hole 72, cutting the sand control shear pin 5 and thus opening the sand flushing port 71, so that the pressure transmission hole 72 and the sand flushing port 71 are connected.

[0057] After the pressure transmission hole 72 is connected to the sand flushing port 71, the fluid in the central tube 10 can flow sequentially through the pressure transmission hole 72 and the sand flushing port 71 to the annulus between the sand packer 40 and the well casing.

[0058] A spring 4 is provided between the upper axial end of the sand valve 3 and the upper sleeve 2. The spring 4 can provide a downward force to reset the sand valve 3 when the sand valve 3 is not subjected to pressure from the central tube 10.

[0059] In one specific embodiment, the sealing assembly 60 includes a rubber sleeve assembly 61 and a slip assembly 62, which are arranged sequentially from top to bottom on the outer wall of the central tube 10.

[0060] The slip assembly 62 is configured to respond to the radial expansion of the center tube 10 under pressure, thereby securing the center tube 10 to the well casing.

[0061] The rubber sleeve assembly 61 is configured to respond to the pressure of the central tube 10 and expand radially, thereby sealing the annulus between the central tube 10 and the well casing.

[0062] During operation, when the ball is thrown into the central tube 10 and pressure is applied, the slip assembly 62 first responds to the pressure inside the central tube 10, fixing the central tube 10 to the well casing. Then, the rubber sleeve assembly 61 responds to the pressure inside the central tube 10, sealing the annulus between the central tube 10 and the well casing.

[0063] In one specific embodiment, the rubber sleeve assembly 61 includes a rubber sleeve seat 6 fixedly disposed on the outer wall of the central tube 10, a rubber sleeve pressure cap 12 fixedly disposed on the central tube 10 by a second setting shear pin 11, a middle rubber sleeve 9 disposed between the rubber sleeve seat 6 and the rubber sleeve pressure cap 12, end rubber sleeves 8 disposed at both ends of the middle rubber sleeve 9, and an upper piston 15 fixedly disposed at the lower end of the rubber sleeve pressure cap 12 by a first setting shear pin 14. A pressure hole 63 is provided on the tube wall of the central tube 10. The upper piston 15 can move upward in response to the pressure from the pressure hole 63, pushing the rubber sleeve pressure cap 12 to squeeze the end rubber sleeves 8 and the middle rubber sleeve 9, causing the end rubber sleeves 8 and the middle rubber sleeve 9 to expand radially.

[0064] In this embodiment, the second setting shear pin 11 is disposed at the upper end of the rubber tube pressure cap 12, thereby fixing the rubber tube pressure cap 12 to the central tube 10. The upper piston 15 is located between the rubber tube pressure cap 12 and the central tube 10, and the upper piston 15 and the rubber tube pressure cap 12 are fixedly connected by the first setting shear pin 14.

[0065] In a preferred embodiment, an anti-protrusion ring 7 is provided between the end rubber tube 8 at the upper end of the middle rubber tube 9 and the rubber tube seat 6, and another anti-protrusion ring 7 is provided between the end rubber tube 8 at the lower end of the middle rubber tube 9 and the rubber tube pressure cap 12. The anti-protrusion rings 7 can prevent the edge of the end rubber tube 8 from protruding during the compression process of the middle rubber tube 9 and the end rubber tube 8, thus preventing it from affecting the seal.

[0066] The slip assembly 62 includes a lower piston 17 fixed to the outer wall of the central tube 10 by a first setting shear pin 14. An upper cone 18 and a lower cone 20 are also provided on the outer wall of the central tube 10. A cylindrical slip 19 is provided on the outer wall of the upper cone 18 and the lower cone 20. The lower piston 17 can move downward in response to the pressure from the pressure hole 63, thereby pushing the upper cone 18 to move downward relative to the lower cone 20, thereby causing the cylindrical slip 19 to expand radially and fix the central tube 10 to the inner wall of the well casing.

[0067] Specifically, the upper inner wall of the lower piston 17 is radially connected to the lower outer wall of the rubber sleeve cap 12, and the first setting shear pin 14 is located at the position where the lower piston 17 and the rubber sleeve cap 12 are radially connected.

[0068] In a preferred embodiment, a double-sided retaining spring 16 is provided between the inner wall of the lower piston 17 and the outer wall of the upper piston 15. The double-sided retaining spring 16 enables the lower piston 17 to move only downward relative to the upper piston 15 and not in the opposite direction, so that after the lower piston 17 and the upper piston 15 respectively push the cylindrical slip 19, the middle rubber cylinder 9, etc. to expand radially, the lower piston 17 and the upper piston 15 can be locked by the double-sided retaining spring 16.

[0069] The setting process of the sand packer 40 is as follows.

[0070] In this embodiment, the lower part of the sand-proof packer 40 is connected to the tubular column with a ball seat (not shown in the figure).

[0071] First, a soluble ball (not shown in the figure) is inserted into the central tube 10 until it fits the ball seat. Then, completion fluid is injected into the central tube 10 to pressurize it. The completion fluid flows in through the pressure hole 63 and acts on the upper piston 15 and the lower piston 17. The lower piston 17 is driven by the pressure of the fluid to move the double-sided retaining ring 16 downward, shearing the first setting shear pin 14 between the lower piston 17 and the rubber sleeve cap 12, pushing the upper cone 18 downward. There is an axial gap between the upper cone 18 and the lower cone 20, and the lower cone 20 is fixed relative to the central tube 10, so that the upper cone 18 can move downward relative to the lower cone 20, causing the cylindrical slip 19 to be axially compressed and radially expanded and extended, anchoring to the inner wall of the well casing.

[0072] After the cylindrical slip 19 extends and anchors, the upper piston 15, under hydraulic pressure, pushes the rubber sleeve cap 12 upward, shearing the second setting shear pin 11 connecting the rubber sleeve cap 12 and the central tube 10, compressing the end rubber sleeve 8 and the middle rubber sleeve 9. At this time, the anti-protrusion ring 7 deforms to prevent the edge of the end rubber sleeve 8 from bulging and affecting the seal. The upper sleeve 2 is fixedly connected to the central tube 10 and threadedly connected to the rubber sleeve seat 6. When the middle rubber sleeve 9 and the end rubber sleeve 8 are compressed by the lower rubber sleeve cap 12, the rubber sleeve seat 6 and the upper sleeve 2 remain relatively fixed to the central tube 10. Therefore, the rubber sleeve assembly 61 can achieve compression setting.

[0073] When the upper piston 15 moves upward to the rubber sleeve compression setting, the upper piston 15 and the lower piston 17 are locked with the double-sided retaining ring 16 respectively, so that the upper piston 15 and the lower piston 17 cannot move backward, preventing the cylindrical slip 19 from retracting and preventing the rubber sleeve from returning to its original state, thereby achieving long-term fixed setting.

[0074] During geothermal water extraction and reinjection, the vertical movement of the tubing caused by temperature changes or other forces can reduce the sealing effect of the packer. Therefore, a packer with cylindrical slips 19 is used. After the packer is set, the slip teeth of the cylindrical slips 19 firmly grip the inner wall of the well casing, thereby greatly reducing the impact of tubing vertical movement on the seal.

[0075] The sand flushing process of the sand-proof packer is as follows.

[0076] Soluble balls are placed in the central tube 10, and then liquid is injected from the central tube 10 to pressurize it. The liquid will flow into the pressure transmission hole 72 and act on the sand valve 3, pushing the sand valve 3 to move upward.

[0077] As the sand control valve 3 moves relative to the upper sleeve 2, the sand control shear pin 5 will be sheared off. The sand control valve 3 moves upward, and the compression spring 4 is exposed at the same time. Liquid will enter the annulus between the sand control packer 40 and the well casing through the pressure transmission hole 72 and the sand control port 71, thereby carrying the rock cuttings and solid precipitates deposited above the rubber sleeve assembly 61 of the sand control packer 40 out of the annulus from the wellhead.

[0078] It is easy to understand that the strength of the sand-proof shear pin 5 is greater than that of the second setting shear pin 11 and the first setting shear pin 14, while the strengths of the second setting shear pin 11 and the first setting shear pin 14 are not limited. Specifically, the strength of each shear pin can be controlled by controlling the diameter of each shear pin, thereby preventing the sand-proof valve 3 from activating prematurely before the packer is set.

[0079] According to the present invention, an elastic claw sleeve 22 is fixedly provided at the lower end of the central tube 10, and a lower connecting sleeve 21 is provided at the lower end of the lower cone 20. The lower connecting sleeve 21 and the elastic claw sleeve 22 are axially fixed. The elastic claw sleeve 22 is configured to be able to release the axial fixation with the lower connecting sleeve 21 under the action of the unsealing tool.

[0080] The structure for unsealing the sand packer 40 includes a lower connecting sleeve 21, an elastic claw sleeve 22, and an elastic claw support sleeve 23.

[0081] Specifically, a lower connecting sleeve 21 is fixedly installed at the lower end of the lower cone 20, and an elastic claw sleeve 22 is fixedly installed at the lower end of the central tube 10. The elastic claw sleeve 22 is located inside the lower connecting sleeve 21. The outer wall of the lower end of the elastic claw sleeve 22 is connected to the inner wall of the lower connecting sleeve 21 by a toothed buckle or other types of mutually compatible retaining rings and grooves. Before the elastic claw sleeve 22 retracts radially, the elastic claw sleeve 22 cannot move axially relative to the lower connecting sleeve 21.

[0082] An elastic claw support sleeve 23 is fixedly connected to the inner wall of the lower end of the elastic claw sleeve 22 by a first unsealing shear pin 24. Before the first unsealing shear pin 24 is cut, the elastic claw support sleeve 23 supports the elastic claw sleeve 22, preventing the elastic claw sleeve 22 from contracting radially, thus preventing the elastic claw sleeve 22 from moving axially relative to the lower connecting sleeve 21. At this time, the lower cone 20 is fixedly connected to the central tube 10 through the lower connecting sleeve 21 and the elastic claw sleeve 22. After the first unsealing shear pin 24 is cut, the elastic claw support sleeve 23 moves axially relative to the elastic claw sleeve 22, and the elastic claw sleeve 22 can contract radially. At this time, the elastic claw sleeve 22 can move axially relative to the lower connecting sleeve 21.

[0083] like Figure 2 As shown, the unsealing tool 200 mainly includes a lower central tube 27, a claw limiting sleeve 28, a reset spring 29, an unsealing elastic claw 30, and an unsealing support ring 31.

[0084] The chuck limiting sleeve 28 is fixed to the outer wall of the lower central tube 27. The release elastic claw 30 is axially slidably sleeved on the chuck limiting sleeve 28. Shoulders 281 are provided at both axial ends of the chuck limiting sleeve 28 to limit the axial movement range of the release elastic claw 30. A return spring 29 is provided between the upper shoulder 281 of the chuck limiting sleeve 28 and the release elastic claw 30. The inner diameter of the release elastic claw 30 is larger than the outer diameter of the lower central tube 27, and there is a gap between the lower end of the release elastic claw 30 and the lower central tube 27, allowing the lower end of the release elastic claw 30 to retract inward under radial pressure.

[0085] The unsealing support ring 31 is fixedly mounted on the lower central tube 27. A support ring step 311 is provided at the upper end of the unsealing support ring 31. Under the action of the return spring 29, the unsealing elastic claw 30 presses down against the support ring step 311.

[0086] Based on the above structure, the specific process of unsealing the sand seal 40 is as follows.

[0087] The sand packer 40 is released using wire rope work. Commonly used basic wire rope work tools include wire rope caps, weighted rods, shock absorbers, and universal joints, which are existing technologies and will not be described in detail here.

[0088] The structure of the release tool 200 for the sand packer 40 is as follows: Figure 2 As shown, the unsealing tool 200 is connected to the bottom of the wireline basic tool string, and the wireline basic tool string carries the unsealing tool 200 into the well.

[0089] like Figure 2a As shown, at this time, the lower end of the unsealing elastic claw 30 of the unsealing tool 200 is located above the elastic claw support sleeve 23 of the sand seal 40. The outer diameter of the unsealing elastic claw 30 is larger than the inner diameter of the elastic claw support sleeve 23 when there is no external force. As the unsealing tool 200 continues to be lowered, the unsealing elastic claw 30 will axially abut against the elastic claw support sleeve 23. Then, the lower central tube 27 carries the elastic claw support sleeve 23 to continue to move down, and the unsealing elastic claw 30 can disengage from the support ring step 311. At this time, the unsealing elastic claw 30 can radially shrink to a size smaller than the inner diameter of the elastic claw support sleeve 23, thereby passing through the elastic claw support sleeve 23 and reaching the bottom of the elastic claw support sleeve 23.

[0090] like Figure 2b As shown, after the release elastic claw 30 reaches below the elastic claw support sleeve 23, the return spring 29 causes the release elastic claw 30 to move down and re-abut against the support ring step 311. At this time, when the lower central tube 27 is lifted, the release elastic claw 30 will axially abut against the lower end of the elastic claw support sleeve 23. Since the release elastic claw 30 is blocked by the support ring step 311 and cannot retract radially, the release elastic claw 30 will drive the elastic claw support sleeve 23 to move upward under the action of the lower central tube 27 and the release support ring 31. The first release shear pin 24 between the elastic claw support sleeve 23 and the elastic claw sleeve 22 of the sand seal 40 is cut off. The elastic claw support sleeve 23 moves upward with the release tool 200, releasing the restriction on the elastic claw sleeve 22. Then the elastic claw sleeve 22 can release the connection structure between the elastic claw sleeve 22 and the lower connecting sleeve 21 by radial retraction, so that the connection between the elastic claw sleeve 22 and the lower connecting sleeve 21 is lost, and thus the slip assembly 62 can no longer restrict the axial movement of the central tube 10.

[0091] Then, the central tube 10 is lifted, and the central tube 10 moves the rubber sleeve seat 6 and the upper sleeve 2 upward, so that the upper part of the end rubber sleeve 8 and the middle rubber sleeve 9 loses the compressive force. At this time, the rubber sleeve assembly 61 will gradually recover under the action of the restoring force.

[0092] There is a gap between the upper end of the upper cone 18 and the central tube 10, meaning that the inner diameter of the upper end of the upper cone 18 is larger than the outer diameter of the central tube 10. An expansion ring 13 is installed in this gap and is fixedly connected to the central tube 10. When the central tube 10 is lifted, the expansion ring 13 moves upward, thereby driving the lower piston 17, the rubber sleeve cap 12, the upper piston 15, and the double-sided retaining spring 16 to move upward, causing the upper cone 18 to lose its compressive force, the cylindrical retainer 19 to retract, and the anchoring of the retainer assembly 62 to be released.

[0093] The radial dimension of the elastic claw sleeve 22 is larger than that of the lower cone 20. There is a certain distance between the axial top end of the elastic claw sleeve 22 and the axial lower end of the lower cone 20. When the elastic claw sleeve 22 moves upward relative to the lower cone 20 by a certain distance, the upper end of the elastic claw sleeve 22 will axially abut against the lower end of the lower cone 20.

[0094] Combined with the above unsealing process, after the anchoring of the slip assembly 62 is released, the upper end of the elastic claw sleeve 22 will axially abut against the lower end of the lower cone 20. Continue to lift the central tube 10, and the central tube 10 will be able to move the entire sand packer 40 upward until it is pulled out of the wellhead.

[0095] The steel wire operation process is simple, has high recycling efficiency, and low economic cost, highlighting its advantages for use in geothermal wells.

[0096] Example 2:

[0097] According to the present invention, a layered extraction and irrigation process is also provided, in which the shallow geothermal layer 39 and the deep geothermal layer 42 are separated by the sand-blocking packer provided according to the present invention, and the shallow geothermal layer 39 and the deep geothermal layer 42 are extracted respectively.

[0098] like Figure 3 As shown, geothermal water extraction employs a two-layer extraction method to improve resource utilization and save extraction costs. The extraction process is as follows: After the central tubing 37 is lowered and the sand packer 40 is set, the two geothermal reservoirs, the shallow geothermal layer 39 with a lower temperature and the deep geothermal layer 42 with a higher temperature, are separated. An annulus 36 is formed between the central tubing 37 and the shallow perforated casing 38. A water pump 35 is installed in both the central tubing 37 and the annulus 36. The top of the annulus 36 is connected to the outlet pipeline of the low-temperature geothermal water (not shown in the figure) through the lower part 34 of the water intake four-way connector, and the top of the central tubing 37 is connected to the outlet pipeline of the high-temperature geothermal water (not shown in the figure) through the upper part 33 of the water intake four-way connector.

[0099] Water from the shallow geothermal layer 39 enters the annulus 36 through the shallow perforated casing 38. Driven by the pump 35 within the annulus 36, it enters the lower part 34 of the water intake cross-section, thus flowing into the outlet pipeline of the low-temperature geothermal water. Water from the deep geothermal layer 42 enters the central oil pipe 37 through the deep sand-control screen pipe 41. Driven by the pump 35 within the central oil pipe 37, it enters the upper part 33 of the water intake cross-section, thus flowing into the outlet pipeline of the high-temperature geothermal water. Depending on the outlet temperature, the geothermal water, after passing through the heat exchanger, can be used for heating, greenhouse irrigation, hot springs, power generation, etc.

[0100] Example 3:

[0101] According to the present invention, a stratified extraction and irrigation process is also provided, in which the shallow geothermal layer 39 and the deep geothermal layer 42 are separated by a sand-blocking packer provided according to the present invention, the used deep geothermal water is reinjected into the deep geothermal layer 42, and the used shallow geothermal water is reinjected into the shallow geothermal layer 39.

[0102] Consistent with the stratified geothermal water extraction approach in Example 2 above, during reinjection, the used shallow geothermal tailwater is introduced into the shallow geothermal layer 39 of the reinjection well through the annulus 36, while the used deep geothermal tailwater is introduced into the deep geothermal layer 42 of the reinjection well through the central tubing 37. This prevents contamination between geothermal water from different reservoirs. Furthermore, to improve extraction and injection efficiency and reduce costs, two geothermal extraction wells are typically paired with one reinjection well, or multiple geothermal extraction wells are paired with one reinjection well. This requires calculating a reasonable combination based on reservoir characteristics and extraction / injection volume.

[0103] Example 4:

[0104] According to the present invention, a layered extraction and injection process is also provided, in which the shallow geothermal layer 39 and the deep geothermal layer 42 are separated by a sand-blocking packer provided according to the present invention, the deep geothermal layer 42 is extracted, and the used geothermal water is reinjected into the shallow geothermal layer 39.

[0105] In this embodiment, the central oil pipe 37 in Embodiment 2 is replaced with an insulated pipe. The deep geothermal water 42 enters the insulated pipe through the deep sand-control screen pipe 41. Driven by the water pump 35 inside the insulated pipe, it enters the upper part 33 of the water intake cross-section, thus entering the outlet pipeline of the high-temperature geothermal water. The geothermal water that has undergone superheat exchange can be reinjected into the annulus 36 through the lower part 34 of the water intake cross-section, thereby entering the formation through the shallow perforated casing 38. This method replenishes the formation pressure, allowing more deep geothermal water to be extracted through the insulated pipe.

[0106] The advantage of the sand packer 40 in this invention lies in the fact that conventional sand packer well-washing operations typically involve injecting washing fluid into the annulus, through a special channel inside the sand packer, into the tubing, flushing the deposits on top of the sand packer into the well bottom or even the reservoir. Considering the significant differences in composition among different geothermal waters, directly flushing the deposits on top of the packer into the reservoir could contaminate the reservoir. Therefore, the sand packer 40 provided by this invention can carry deposited rock cuttings and solid precipitates out of the annulus and out of the wellhead, preventing deposits from accumulating on top of the packer and affecting its release.

[0107] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0108] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0109] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sand-proof packer, characterized in that, include: Central tube (10); A sealing assembly (60) is disposed on the outer wall of the central tube (10). The sealing assembly (60) includes a rubber sleeve assembly (61) and a slip assembly (62) disposed sequentially from top to bottom on the outer wall of the central tube (10). The sealing assembly (60) is configured to be able to expand radially in response to the pressure inside the central tube (10) to complete the sealing. The rubber sleeve assembly (61) includes: a rubber sleeve seat (6) fixedly disposed on the outer wall of the central tube (10); a rubber sleeve pressure cap (12) fixedly disposed on the central tube (10) by a second setting screw (11); a middle rubber sleeve (9) disposed between the rubber sleeve seat (6) and the rubber sleeve pressure cap (12); end rubber sleeves (8) disposed at both ends of the middle rubber sleeve (9); and an upper piston (15) fixedly disposed at the lower end of the rubber sleeve pressure cap (12) by a first setting screw (14), and a pressure hole (63) is provided on the tube wall of the central tube (10). The slip assembly (62) includes a lower piston (17) fixed to the outer wall of the central tube (10) by a first set-seal shear pin (14), and an upper cone (18) and a lower cone (20) are also provided on the outer wall of the central tube (10). A cylindrical slip (19) is provided on the outer wall of the upper cone (18) and the lower cone (20). A sand flushing assembly (70) is disposed on the central tube (10) and located above the packer assembly (60). The sand flushing assembly (70) is configured to open in response to the pressure inside the central tube (10), allowing fluid inside the central tube (10) to flow through the sand flushing assembly (70) to the outside of the central tube (10), carrying the sand and gravel above the packer assembly (60) outside the central tube (10) to the wellhead. The sand flushing assembly (70) includes: an upper sleeve (2), the upper sleeve ( 2) The upper end is fixedly installed on the outer wall of the central tube (10), and a sand flushing port (71) is provided on the upper sleeve (2); sand prevention valve (3), the sand prevention valve (3) is located between the upper sleeve (2) and the central tube (10), a pressure transmission hole (72) is provided on the tube wall of the central tube (10), the sand prevention valve (3) is configured to be able to move axially in response to the pressure from the pressure transmission hole (72), thereby opening the sand flushing port (71) and making the pressure transmission hole (72) communicate with the sand flushing port (71).

2. The sand-proof sealing device according to claim 1, characterized in that, The sand valve (3) is fixedly connected to the upper sleeve (2) by sand shear pins (5).

3. The sand-proof sealing device according to claim 2, characterized in that, A spring (4) is provided between the upper axial end of the sand valve (3) and the upper sleeve (2).

4. The sand-proof sealing device according to claim 1, characterized in that, The lower end of the upper sleeve (2) is in contact with the upper end of the sealing assembly (60).

5. The sand-proof seal according to any one of claims 1 to 4, characterized in that, The slip assembly (62) is configured to radially expand in response to the pressure of the central tube (10), thereby fixing the central tube (10) to the well casing. The rubber sleeve assembly (61) is configured to respond to the pressure of the central tube (10) to radially expand, thereby sealing the annulus between the central tube (10) and the well casing.

6. The sand-proof seal according to claim 5, characterized in that, The upper piston (15) can move upward in response to the pressure from the pressure hole (63), pushing the rubber tube cap (12) to squeeze the end rubber tube (8) and the middle rubber tube (9), causing the end rubber tube (8) and the middle rubber tube (9) to expand radially.

7. The sand-proof sealing device according to claim 6, characterized in that, The lower piston (17) is able to move downward in response to pressure from the pressure hole (63), thereby pushing the upper cone (18) downward relative to the lower cone (20), which in turn causes the cylindrical slip (19) to expand radially.

8. The sand-proof seal according to claim 7, characterized in that, An elastic claw sleeve (22) is fixedly provided at the lower end of the central tube (10), and a lower connecting sleeve (21) is provided at the lower end of the lower cone (20). The lower connecting sleeve (21) is axially fixed to the elastic claw sleeve (22), and the elastic claw sleeve (22) is configured to release the axial fixation with the lower connecting sleeve (21) under the action of the unsealing tool.

9. A stratified irrigation and harvesting process, characterized in that, The shallow geothermal layer (39) and the deep geothermal layer (42) are separated by a sand-blocking packer according to any one of claims 1 to 8, and the shallow geothermal layer (39) and the deep geothermal layer (42) are mined respectively.

10. A stratified irrigation and harvesting process, characterized in that, The shallow geothermal layer (39) is separated from the deep geothermal layer (42) using any one of claims 1 to 8, the deep geothermal layer (42) is mined, and the used geothermal water is reinjected into the shallow geothermal layer (39).

11. A stratified irrigation and harvesting process, characterized in that, The shallow geothermal layer (39) and the deep geothermal layer (42) are separated by a sand-blocking device according to any one of claims 1 to 8, and the used deep geothermal water is reinjected into the deep geothermal layer (42) and the used shallow geothermal water is reinjected into the shallow geothermal layer (39).

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