Sand control packer and layered mining and filling process

Abstract

The invention belongs to the technical field of geothermal wells, and particularly relates to a sand control packer and a layered mining and filling process. The sand prevention packer comprises a central pipe; the packing assembly is arranged on the outer wall of the central pipe, and the packing assembly is arranged to be capable of responding to pressure in the central pipe to expand in the radial direction to complete packing; the sand washing assembly is arranged on the central pipe and located above the packing assembly, and the sand washing assembly is arranged to be capable of responding to the pressure in the central pipe to be opened, so that fluid in the central pipe flows to the outside of the central pipe through the sand washing assembly. And gravel above the packing assembly outside the central pipe is brought to a well mouth. According to the packer, gravel can be cleaned under the condition that the packer is buried by the gravel and the like, and therefore the packer can be deblocked conveniently.

Description

Technical Field

[0001] The present invention belongs to the technical field of geothermal wells, and in particular, relates to a sand control packer and a layered production and irrigation process. Background Art

[0002] Geothermal resources, as a clean energy source, can be used for hot springs, heating, power generation, irrigation, etc. Currently, all countries are vigorously developing geothermal resources.

[0003] At present, geothermal wells generally adopt general extraction and irrigation, which has low utilization rate of geothermal resources and easily causes groundwater pollution. Geothermal water wells have serious sand production. At present, the main sand control methods used in geothermal water wells are chemical sand control and mechanical sand control.

[0004] In actual use, the application effect of chemical sand control is poor.

[0005] When mechanical sand control is used, sand or solid precipitation occurs in the formation above the packer, and the sand or solid precipitation will accumulate on the upper part of the packer, directly causing the pipe string and the packer to be buried in sand, thereby increasing the resistance when the packer is unsealed, making it impossible to unseal. If the wellbore casing is a differential pressure packer, the gap between the packer rubber tube and the wellbore is small, and the bridging effect of large pieces of sand will also cause the pipe string and the packer to be buried in sand. Once the pipe string is buried in sand, when the pipe string is lifted, the friction resistance of the sand-buried pipe string is large, making it impossible to unseal the packer and repair the well.

[0006] Chinese patent document CN211008559U discloses a drillable well wash packer. When washing a well, the casing annulus is pressurized, and the liquid in the casing annulus enters the annular space between the rubber tube seat and the upper outer sleeve through the gap between the T-shaped sealant ring pressure cap and the J-shaped sealant ring, and pushes the well washing sliding sleeve upward to open the well washing fluid inlet on the central pipe wall. At this time, the well washing fluid in the casing annulus above the sealant tube reaches the casing annulus below the sealant tube through the well washing channel and the guide hole on the lower pressure ring of the rubber tube to carry out the well washing operation. When washing a geothermal well by sand flushing, it is necessary to flush away the sediment on the top of the packer. If the casing annulus is pressurized for well washing, the well washing fluid will directly enter the upper geothermal reservoir and cannot flush away the sediment on the top of the packer. Therefore, it is necessary to design a sand-proof and easy-to-release packer to provide tool hard support for realizing stratified production and irrigation of geothermal wells.

[0007] In addition, 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 consisting of a geothermal well, an inner pipe and a sealing assembly, wherein the inner pipe is arranged 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 arranged in the annular channel, and the annular channel is divided into an upper section and a lower section, the upper section and the lower section 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 same-well extraction and injection. Summary of the invention

[0008] In view of the above-mentioned technical problems, the present invention aims to provide a sand control packer, which can clean the gravel when the packer is buried by gravel, thereby facilitating the unsealing of the packer.

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

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

[0011] Central tube;

[0012] A packing assembly, the packing assembly is arranged on the outer wall of the central tube, and the packing assembly is arranged to expand radially in response to the pressure in the central tube to complete the packing;

[0013] A sand flushing assembly is arranged on the central pipe and located above the isolation assembly. The sand flushing assembly is configured to be opened in response to the pressure in the central pipe, so that the fluid in the central pipe flows to the outside of the central pipe through the sand flushing assembly, and the sand and gravel above the isolation assembly outside the central pipe are brought to the wellhead.

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

[0015] An upper sleeve, the upper end of which is fixedly arranged on the outer wall of the central tube, and a sand flushing port is arranged on the upper sleeve;

[0016] A sand prevention valve is located between the upper sleeve and the center tube. A pressure transmission hole is provided on the tube wall of the center tube. The sand prevention valve is configured to be able to move axially in response to the 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 control valve is fixedly connected to the upper sleeve via sand control shear pins.

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

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

[0020] In a preferred embodiment, the packing assembly comprises a rubber cartridge assembly and a slip assembly which are sequentially arranged on the outer wall of the central tube from top to bottom.

[0021] The slip assembly is configured to expand radially in response to pressure of the base pipe, thereby securing the base pipe to the wellbore casing.

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

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

[0024] A rubber tube seat fixedly arranged on the outer wall of the central tube;

[0025] A rubber cylinder pressure cap arranged on the central tube is fixed by a second setting shear pin;

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

[0027] End rubber cylinders arranged at both ends of the middle rubber cylinder;

[0028] And an upper piston fixedly arranged at the lower end of the rubber tube pressure cap by a first sealing shear pin, a pressure hole is arranged on the tube wall of the central tube, and the upper piston can move upward in response to the pressure from the pressure hole, pushing the rubber tube pressure cap to squeeze the end rubber tube and the middle rubber tube, so that the end rubber tube and the middle rubber tube expand radially.

[0029] In a preferred embodiment, the cava assembly includes a lower piston fixed on the outer wall of the center tube by a first sealing shear pin, an upper cone and a lower cone are also provided on the outer wall of the center tube, and cylindrical cava are provided on the outer walls of the upper cone and the lower cone. The lower piston can move downward in response to the pressure from the pressure hole, thereby pushing the upper cone to move downward relative to the lower cone, thereby causing the cylindrical cava 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 a desealing tool.

[0031] According to the present invention, a stratified production and irrigation process is also provided, which uses the sand control packer provided by the present invention to separate the shallow geothermal water layer from the deep geothermal water layer, and respectively produces the shallow geothermal water layer and the deep geothermal water layer.

[0032] According to the present invention, a stratified extraction and injection process is also provided, which uses the sand-proof seal provided by the present invention to separate the shallow geothermal water layer from the deep geothermal water layer, extracts the deep geothermal water layer, and injects the used geothermal water back into the shallow geothermal water layer.

[0033] According to the present invention, a stratified production and injection process is also provided, which uses the sand-proof seal provided by the present invention to separate the shallow geothermal water layer from the deep geothermal water layer, and re-injects the used deep geothermal water into the deep geothermal water layer, and re-injects the used shallow geothermal water into the shallow geothermal water layer.

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

[0035] Before the sand control packer of the present invention is unsealed, the pressure is firstly transmitted to the sand control valve through the pressure transmission hole by means of pressurizing the inside of the central tube, so that the sand control valve moves axially, and then the sand flushing port is opened. After the sand flushing port is opened, it is connected with the pressure transmission hole. At this time, the fluid in the central tube can pass through the pressure transmission hole and the sand flushing port to flush the sand and gravel accumulated outside the packer, and send the sand and gravel to the wellhead, thereby facilitating the unsealing of the packer.

[0036] The layered mining and irrigation process uses the sand control packer provided by the present invention to separate the deep geothermal water layer and the shallow geothermal water layer, so that different layers can be mined simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0038] Figure 1 A schematic diagram showing an embodiment of a sand control packer according to the present invention;

[0039] Figure 2 A schematic diagram showing an embodiment of a tool for releasing a sand control packer according to the present invention;

[0040] Figure 2a and Figure 2b A schematic diagram showing a release tool according to the present invention passing through an elastic claw support sleeve of a sand control packer, Figure 2a and Figure 2b It is only used to simply indicate the positional relationship between the unsealing tool and the elastic claw support sleeve;

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

[0042] In the figure:

[0043] 1. Upper joint; 70. Sand flushing assembly; 71. Sand flushing port; 72. Pressure transmission hole; 2. Upper sleeve; 3. Sand control valve; 4. Spring; 5. Sand control shear pin; 60. Packing assembly; 61. Rubber cylinder assembly; 62. Slip assembly; 63. Pressure hole; 6. Rubber cylinder seat; 7. Anti-burst ring; 8. End rubber cylinder; 9. Middle rubber cylinder; 10. Center pipe; 11. Second sealing shear pin; 12. Rubber cylinder pressure cap; 13. Expansion ring; 14. First sealing shear pin; 15. Upper piston; 16. Double-sided retaining ring; 17. Lower piston; 18. Upper cone; 19. Cylindrical slip; 20. Lower cone; 21. Lower connecting sleeve; 22. Elastic Claw sleeve; 23. Elastic claw support sleeve; 24. First unsealing shear nail; 25. Lower joint; 26. Unsealing upper joint; 27. Lower center pipe; 28. Claw limit sleeve; 281. Shaft shoulder; 29. ​​Reset spring; 30. Unsealing elastic claw; 31. Unsealing support ring; 311. Support ring step; 32. Guide head; 33. Upper part of water production spool; 34. Lower part of water production spool; 35. Water pump; 36. Oil casing annulus; 37. Center oil pipe; 38. Shallow perforating casing; 39. Shallow geothermal water; 40. Sand control packer; 41. Deep sand control screen; 42. Deep geothermal water; 200. Unsealing tool.

[0044] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

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

[0046] It should be noted that, in the present application, the direction close to the wellhead after entering the well according to the present invention is described as "up" or similar terms, that is, Figure 1 The direction away from the wellhead is described as "down" or similar terms, i.e. Figure 1 Below.

[0047] Embodiment 1:

[0048] Figure 1 The structure of the sand control packer 40 according to the present invention is shown. Figure 1 As shown, the sand control packer 40 includes a base pipe 10 , a packer assembly 60 and a sand flushing assembly 70 .

[0049] The packing assembly 60 is arranged on the outer wall of the central pipe 10, and the central axis of the packing assembly 60 coincides with the central axis of the central pipe 10. The packing assembly 60 is arranged to expand radially in response to the pressure in the central pipe 10 to complete the packing.

[0050] The sand flushing assembly 70 is arranged on the central pipe 10, above the isolation assembly 60, and the central axis of the sand flushing assembly 70 coincides with the central axis of the central pipe 10. The sand flushing assembly 70 is arranged to be opened in response to the pressure in the central pipe 10, so that the fluid in the central pipe 10 flows to the outside of the central pipe 10 through the sand flushing assembly 70, and the gravel above the isolation assembly 60 outside the central pipe 10 is brought to the wellhead.

[0051] Specifically, during the working process, the sand control packer 40 enters the wellbore casing (not shown in the figure). When isolation is required, a ball is thrown into the central pipe 10 to build up pressure, and then the isolation assembly 60 expands radially in response to the pressure in the central pipe 10, thereby closing the annulus between the central pipe 10 and the wellbore casing.

[0052] Due to the serious sand production in the geothermal water well, the annulus between the central tube 10 and the wellbore casing is often buried by gravel, which increases the friction resistance between the packer and the wellbore casing during the unsealing process, causing difficulty in unsealing. When the sand-proof packer 40 provided by the present invention needs to be unsealed, the pressure is held by throwing a ball into the central tube 10, and then the sand flushing assembly 70 is opened in response to the pressure in the central tube 10, so that the fluid in the central tube 10 flows to the outside of the central tube 10 through the sand flushing assembly 70, that is, the fluid with a certain pressure enters the annulus between the central tube 10 and the wellbore casing. Under the blockage of the sand-proof packer 40, the fluid can only flow toward the wellhead with the accumulated gravel, thereby bringing the gravel above the packing assembly 60 to the wellhead, which is convenient for movement during unsealing.

[0053] It is easy to understand that the structure used for ball pitching and pressure holding in the central tube 10 is a prior art 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 diameter of the upper end of the upper sleeve 2 is smaller than that of the middle and lower part, so that the upper end of the upper sleeve 2 is fixedly arranged on the outer wall of the central tube 10, there is a gap between the middle and lower part of the upper sleeve 2 and the central tube 10, and a sand flushing port 71 is arranged on the upper sleeve 2, and the sand flushing port 71 connects the inner side and the outer side 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, the sand control valve 3 is located between the middle and lower part of the upper sleeve 2 and the central tube 10. The sand control valve 3 is fixedly connected to the upper sleeve 2 through the sand control shear nails 5, and the sand control valve 3 closes the sand flushing port 71. A pressure transmission hole 72 is provided on the wall of the central tube 10, and the sand control valve 3 is configured to be able to move axially in response to the pressure from the pressure transmission hole 72, shorten the sand control shear nails 5, and then open the sand flushing port 71, so that the pressure transmission hole 72 is connected to the sand flushing port 71.

[0057] After the pressure transmission hole 72 is connected to the sand flushing port 71 , the fluid in the central pipe 10 can flow into the annulus between the sand control packer 40 and the wellbore casing through the pressure transmission hole 72 and the sand flushing port 71 in sequence.

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

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

[0060] The slip assembly 62 is configured to expand radially in response to pressure of the base pipe 10, thereby securing the base pipe 10 to the wellbore casing.

[0061] The rubber sleeve assembly 61 is configured to expand radially in response to the pressure of the central pipe 10 , thereby isolating the annulus between the central pipe 10 and the wellbore casing.

[0062] During operation, when the ball is dropped into the center pipe 10 to build up pressure, the slip assembly 62 first responds to the pressure in the center pipe 10 to fix the center pipe 10 to the wellbore casing, and then the rubber sleeve assembly 61 responds to the pressure in the center pipe 10 to seal the annulus between the center pipe 10 and the wellbore casing.

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

[0064] In this embodiment, the second setting shear pin 11 is arranged at the upper end of the rubber cylinder pressure cap 12, so as to fix the rubber cylinder pressure cap 12 with the center tube 10. The upper piston 15 is located between the rubber cylinder pressure cap 12 and the center tube 10, and the upper piston 15 and the rubber cylinder pressure cap 12 are fixedly connected by the first setting shear pin 14.

[0065] In a preferred embodiment, an anti-bulging 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-bulging 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 provision of the anti-bulging ring 7 can prevent the edge of the end rubber tube 8 from bulging and affecting the sealing during the extrusion process of the middle rubber tube 9 and the end rubber tube 8.

[0066] The cava assembly 62 includes a lower piston 17 fixed on the outer wall of the center pipe 10 by a first sealing shear pin 14, an upper cone 18 and a lower cone 20 are also provided on the outer wall of the center pipe 10, and a cylindrical cava 19 is provided on the outer walls 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, and then causing the cylindrical cava 19 to expand radially, thereby fixing the center pipe 10 to the inner wall of the wellbore casing.

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

[0068] In a preferred embodiment, a double-sided circlip 16 is provided between the inner wall of the lower piston 17 and the outer wall of the upper piston 15. The double-sided circlip 16 enables the lower piston 17 to move downward only relative to the upper piston 15, but not to move in the opposite direction, so that after the lower piston 17 and the upper piston 15 respectively push the cylindrical slips 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 circlip 16.

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

[0070] In this embodiment, the lower portion of the sand control packer 40 is connected to a pipe string with a ball seat (not shown in the figure).

[0071] First, a soluble ball (not shown in the figure) is put into the central tube 10 until the soluble ball fits with the ball seat. Then, completion fluid is injected from the central tube 10 to pressurize the well. The completion fluid will flow into the pressure hole 63 and act on the upper piston 15 and the lower piston 17. The lower piston 17 is driven by the pressure of the liquid to drive the double-sided retaining spring 16 to move downward, shearing off the first sealing shear pin 14 between the lower piston 17 and the rubber cylinder pressure cap 12, pushing the upper cone 18 downward, and 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, so that the cylindrical slip 19 is axially compressed, radially expanded and extended, and anchored on the inner wall of the wellbore casing.

[0072] After the cylindrical slip 19 is extended and anchored, the upper piston 15 pushes the rubber tube pressure cap 12 upward under the action of hydraulic pressure, cuts off the second sealing shear pin 11 connecting the rubber tube pressure cap 12 and the center tube 10, and compresses the end rubber tube 8 and the middle rubber tube 9. At this time, the anti-burst ring 7 is deformed to prevent the edge of the end rubber tube 8 from bulging and affecting the seal. The upper sleeve 2 is fixedly connected to the center tube 10, and the upper sleeve 2 is threadedly connected to the rubber tube seat 6. When the middle rubber tube 9 and the end rubber tube 8 are compressed by the lower rubber tube pressure cap 12, the rubber tube seat 6 and the upper sleeve 2 and the center tube 10 remain relatively fixed. Therefore, the rubber tube assembly 61 can achieve compression sealing.

[0073] When the upper piston 15 moves upward to the point where the rubber cylinder is compressed and sealed, the upper piston 15 and the lower piston 17 are respectively locked with the double-sided retaining spring 16, so that the upper piston 15 and the lower piston 17 cannot retreat, thereby preventing the cylindrical slips 19 from retracting and preventing the rubber cylinder from recovering, thereby achieving long-term fixed sealing.

[0074] During geothermal water extraction and reinjection, the up and down creep of the oil pipe caused by temperature changes or other forces will reduce the sealing effect of the packer. Therefore, a packer with a cylindrical slip 19 is used. After the packer is set, the slip teeth of the cylindrical slip 19 firmly clamp the inner wall of the wellbore casing, thereby greatly reducing the influence of the up and down creep of the oil pipe on the sealing.

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

[0076] A soluble ball is put into the central tube 10 , and then liquid is injected from the central tube 10 to pressurize it. The liquid flows into the pressure transmission hole 72 and acts on the sand control valve 3 , pushing the sand control valve 3 to move upward.

[0077] Since the sand control valve 3 and the upper sleeve 2 move relative to each other, the sand control shear pins 5 will be cut off. The sand control valve 3 moves upward, compressing the spring 4 and exposing the sand flushing port 71 at the same time, and the liquid will enter the annulus between the sand control packer 40 and the wellbore casing through the pressure transmission hole 72 and the sand flushing port 71, thereby bringing the rock debris and solid phase precipitation deposited above the rubber sleeve assembly 61 of the sand control packer 40 out of the wellhead from the annulus.

[0078] It is easy to understand that the strength of the sand control shear pin 5 is greater than the strength of the second setting shear pin 11 and the first setting shear pin 14, and there is no limit on the strength of the second setting shear pin 11 and the first setting shear pin 14. Specifically, the purpose of controlling the strength of each shear pin can be achieved by controlling the diameter of each shear pin, thereby avoiding the sand control valve 3 from being activated in advance 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 is axially fixed to the elastic claw sleeve 22, and 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 releasing the sand control packer 40 includes a lower connecting sleeve 21 , an elastic claw sleeve 22 and an elastic claw supporting sleeve 23 .

[0081] Specifically, a lower connecting sleeve 21 is fixedly provided at the lower end of the lower cone 20, and an elastic claw sleeve 22 is fixedly provided at the lower end of the center tube 10. The elastic claw sleeve 22 is located inside the lower connecting sleeve 21, and the outer wall of the lower end portion of the elastic claw sleeve 22 is connected to the inner wall of the lower connecting sleeve 21 by a horse tooth buckle or other types of mutually adaptable clamping ring grooves. Before the elastic claw sleeve 22 is radially contracted, 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 through the first unsealing shear nail 24. Before the first unsealing shear nail 24 is cut off, the elastic claw support sleeve 23 is used to support the elastic claw sleeve 22 to prevent the elastic claw sleeve 22 from radially contracting, so that the elastic claw sleeve 22 cannot move 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 nail 24 is cut off, 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 clamping claw limiting sleeve 28 , a reset spring 29 , an unsealing elastic claw 30 and an unsealing support ring 31 .

[0084] The claw limit sleeve 28 is fixed on the outer wall of the lower center tube 27, and the unsealing elastic claw 30 is axially slidably sleeved on the claw limit sleeve 28. The axial ends of the claw limit sleeve 28 are provided with shaft shoulders 281 for limiting the axial movement range of the unsealing elastic claw 30, and a reset spring 29 is provided between the upper shaft shoulder 281 of the claw limit sleeve 28 and the unsealing elastic claw 30. The inner diameter of the unsealing elastic claw 30 is larger than the outer diameter of the lower center tube 27, and there is a gap between the lower end of the unsealing elastic claw 30 and the lower center tube 27, so that the lower end of the unsealing elastic claw 30 can shrink inward when subjected to radial pressure.

[0085] The unsealing support ring 31 is fixedly arranged on the lower center tube 27 , and a support ring step 311 is arranged at the upper end of the unsealing support ring 31 . Under the action of the return spring 29 , the unsealing elastic claw 30 presses downward against the support ring step 311 .

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

[0087] The sand control packer 40 is unsealed by wire work. Commonly used basic tool strings for wire work include wire rope caps, weight rods, jars, universal joints, etc. These are prior arts and will not be described in detail here.

[0088] The structure of the release tool 200 of the sand control packer 40 is as follows: Figure 2 As shown, the unsealing tool 200 is connected below the basic tool string for wireline operation, and the basic tool string for wireline operation 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 control packer 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. The unsealing tool 200 is continuously lowered, and the unsealing elastic claw 30 will axially abut against the elastic claw support sleeve 23. Then, the lower center pipe 27 continues to move downward with the elastic claw support sleeve 23, and the unsealing elastic claw 30 can be separated from the support ring step 311. At this time, the unsealing elastic claw 30 can radially shrink to a diameter 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 unsealing elastic claw 30 reaches the bottom of the elastic claw support sleeve 23, the reset spring 29 moves the unsealing elastic claw 30 downward to re-contact with the support ring step 311. At this time, the lower center pipe 27 is lifted, and the unsealing elastic claw 30 will axially contact with the lower end of the elastic claw support sleeve 23. Since the unsealing elastic claw 30 is resisted by the support ring step 311 and cannot be radially contracted, the unsealing elastic claw 30 will drive the elastic claw support sleeve 23 to move upward under the action of the lower center pipe 27 and the unsealing support ring 31, and the first unsealing shear nail 24 between the elastic claw support sleeve 23 and the elastic claw sleeve 22 of the sand control packer 40 is cut off, and the elastic claw support sleeve 23 moves upward with the unsealing tool 200, releasing the restriction on the elastic claw sleeve 22, and the elastic claw sleeve 22 can release the connection structure with the lower connecting sleeve 21 by radial contraction, so that the elastic claw sleeve 22 loses connection with the lower connecting sleeve 21, and then the slip assembly 62 cannot restrict the axial movement of the center pipe 10.

[0091] Afterwards, the center tube 10 is lifted up, and the center tube 10 moves up with the rubber tube seat 6 and the upper sleeve 2, so that the upper part of the end rubber tube 8 and the middle rubber tube 9 loses the compression force. At this time, the rubber tube 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, that is, the inner diameter of the upper end of the upper cone 18 is larger than the outer diameter of the central tube 10, and an expansion ring 13 is arranged in this gap, and the expansion ring 13 is fixedly connected to the central tube 10. When the central tube 10 is lifted, the expansion ring 13 will move upward, thereby driving the lower piston 17, the rubber cylinder pressure cap 12, the upper piston 15 and the double-sided retaining spring 16 upward, so that the upper cone 18 loses its compression force, the cylindrical slips 19 retract, and the slip assembly 62 is released from anchoring.

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

[0094] In combination with the above-mentioned 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, and the central pipe 10 will continue to be lifted. The central pipe 10 can then move up with the entire sand control packer 40 until it is lifted out of the wellhead.

[0095] The simple slickline operation process, high recovery efficiency and low economic cost highlight the advantages of using it in geothermal wells.

[0096] Embodiment 2:

[0097] According to the present invention, a stratified production and injection process is also provided, which uses the sand control packer provided by the present invention to separate the shallow geothermal water layer 39 from the deep geothermal water layer 42, and respectively produces the shallow geothermal water layer 39 and the deep geothermal water layer 42.

[0098] like Figure 3 As shown, the exploitation of geothermal water is carried out in two layers, which improves resource utilization and saves exploitation costs. The exploitation process is as follows: the central oil pipe 37 is lowered, and after the sand-proof packer 40 is set, the two heat reservoirs, the shallow geothermal water layer 39 with a lower temperature and the deep geothermal water layer 42 with a higher temperature, are separated. An oil-casing annulus 36 is formed between the central oil pipe 37 and the shallow perforated casing 38, and a water pump 35 is respectively arranged in the central oil pipe 37 and the oil-casing annulus 36. The top of the oil-casing annulus 36 is connected to the outlet water pipeline of the low-temperature geothermal water through the lower part 34 of the water production spool (not shown in the figure), and the top of the central oil pipe 37 is connected to the outlet water pipeline of the high-temperature geothermal water through the upper part 33 of the water production spool (not shown in the figure).

[0099] The water in the shallow geothermal water layer 39 enters the oil casing annulus 36 through the shallow perforated casing 38, and enters the lower part 34 of the water production spool under the pumping power of the water pump 35 in the oil casing annulus 36, and then enters the outlet pipeline of the low-temperature geothermal water; the water in the deep geothermal water layer 42 enters the central oil pipe 37 through the deep sand control screen 41, and enters the upper part 33 of the water production spool under the pumping power of the water pump 35 in the central oil pipe 37, and then enters the outlet pipeline of the high-temperature geothermal water. According to the outlet water temperature, the geothermal water can be used for heating, greenhouse irrigation, hot springs, power generation, etc. after passing through the heat exchanger.

[0100] Embodiment three:

[0101] According to the present invention, a layered production and injection process is also provided, which uses the sand-proof seal provided by the present invention to separate the shallow geothermal water layer 39 from the deep geothermal water layer 42, and re-injects the used deep geothermal water into the deep geothermal water layer 42, and re-injects the used shallow geothermal water into the shallow geothermal water layer 39.

[0102] Consistent with the idea of ​​geothermal water layered exploitation in the second embodiment, during reinjection, the used shallow geothermal water tail water enters the shallow geothermal water layer 39 of the reinjection well through the casing annulus 36, and the used deep geothermal water tail water enters the deep geothermal water layer 42 of the reinjection well through the central oil pipe 37, thereby preventing the contamination of geothermal water between different reservoirs. At the same time, in order to improve the extraction and injection efficiency and reduce the extraction and injection cost, two geothermal extraction wells are usually used to correspond to one reinjection well, or multiple geothermal extraction wells are used to correspond to one reinjection well, which requires a reasonable combination to be calculated based on the reservoir characteristics and the extraction and injection volume.

[0103] Embodiment 4:

[0104] According to the present invention, a layered extraction and injection process is also provided, which uses the sand-proof seal provided by the present invention to separate the shallow geothermal water layer 39 from the deep geothermal water layer 42, extracts the deep geothermal water layer 42, and injects the used geothermal water back into the shallow geothermal water layer 39.

[0105] In this embodiment, the central oil pipe 37 in the second embodiment is replaced with an insulation pipe, so that the deep geothermal water 42 enters the insulation pipe through the deep sand control screen pipe 41, enters the upper part 33 of the water production spool under the pumping power of the water pump 35 in the insulation pipe, and then enters the water outlet pipeline of the high-temperature geothermal water, and the geothermal water that has undergone heat exchange can be re-injected into the oil casing annulus 36 through the lower part 34 of the water production spool, and then enter the formation through the shallow perforated casing 38. In this way, the formation pressure can be supplemented, so that more deep geothermal water can enter and be mined through the insulation pipe.

[0106] The advantage of using the sand control packer 40 in the present invention is that the conventional sand control packer well washing operation usually injects a wash fluid into the casing annulus, and the wash fluid enters the oil pipe through a special channel inside the sand control packer, flushing the sediment on the top of the sand control packer into the bottom of the well or even the reservoir. We consider that different geothermal waters contain different components. If the sediment on the top of the packer is directly flushed into the reservoir, the injected sand flushing liquid may contaminate the reservoir. Therefore, the sand control packer 40 provided by the present invention can be used to bring the deposited rock cuttings and solid phase precipitation out of the casing annulus and out of the wellhead, thereby avoiding the accumulation of sediment on the top of the packer and affecting the unsealing of the packer.

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

[0108] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0109] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0110] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sand control packer, characterized in that: include: Central tube (10); A packing assembly (60), wherein the packing assembly (60) is arranged on the outer wall of the central pipe (10), and the packing assembly (60) is arranged to be able to expand radially in response to the pressure in the central pipe (10) to complete the packing; A sand flushing assembly (70) is arranged on the central pipe (10) and is located above the isolation assembly (60). The sand flushing assembly (70) is configured to be opened in response to the pressure in the central pipe (10), so that the fluid in the central pipe (10) flows through the sand flushing assembly (70) to the outside of the central pipe (10), and the sand and gravel above the isolation assembly (60) outside the central pipe (10) are brought to the wellhead.

2. The sand control packer according to claim 1, characterized in that: The sand flushing assembly (70) comprises: An upper sleeve (2), the upper end of which is fixedly arranged on the outer wall of the central tube (10), and a sand flushing port (71) is arranged on the upper sleeve (2); A 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), and 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 connecting the pressure transmission hole (72) with the sand flushing port (71).

3. The sand control packer according to claim 2, characterized in that: The sand prevention valve (3) is fixedly connected to the upper sleeve (2) via sand prevention shear pins (5).

4. The sand control packer according to claim 3, characterized in that: A spring (4) is arranged between the axial upper end of the sand control valve (3) and the upper sleeve (2).

5. The sand control packer according to claim 2, characterized in that: The lower end of the upper sleeve (2) contacts the upper end of the packing assembly (60).

6. The sand control packer according to any one of claims 1 to 5, characterized in that: The packing assembly (60) comprises a rubber sleeve assembly (61) and a slip assembly (62) which are arranged on the outer wall of the central pipe (10) in sequence from top to bottom. The slip assembly (62) is configured to expand radially in response to the pressure of the central tube (10), thereby fixing the central tube (10) to the wellbore casing. The rubber sleeve assembly (61) is configured to expand radially in response to the pressure of the central pipe (10), thereby isolating the annulus between the central pipe (10) and the wellbore casing.

7. The sand control packer according to claim 6, characterized in that: The rubber cartridge assembly (61) comprises: A rubber cartridge seat (6) fixedly arranged on the outer wall of the central tube (10); A rubber sleeve pressure cap (12) is fixedly arranged on the central tube (10) by means of a second setting shear pin (11); A middle rubber cylinder (9) disposed between the rubber cylinder seat (6) and the rubber cylinder pressure cap (12); End rubber cylinders (8) arranged at both ends of the middle rubber cylinder (9); An upper piston (15) is fixedly arranged at the lower end of the rubber tube pressure cap (12) by a first sealing shear pin (14), and a pressure hole (63) is arranged on the wall of the central tube (10). The upper piston (15) can move upward in response to the pressure from the pressure hole (63), and push the rubber tube pressure cap (12) to squeeze the end rubber tube (8) and the middle rubber tube (9), so that the end rubber tube (8) and the middle rubber tube (9) expand radially.

8. The sand control packer according to claim 7, characterized in that: The slip assembly (62) includes a lower piston (17) fixedly arranged on the outer wall of the center tube (10) by a first sealing shear pin (14); an upper cone (18) and a lower cone (20) are also arranged on the outer wall of the center tube (10); and a cylindrical slip (19) is arranged on the outer walls 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.

9. The sand control packer according to claim 8, characterized in that: An elastic claw sleeve (22) is fixedly arranged at the lower end of the central tube (10), and a lower connecting sleeve (21) is arranged 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 arranged to be able to release the axial fixation with the lower connecting sleeve (21) under the action of a de-sealing tool.

10. A layered irrigation process, characterized in that: A shallow geothermal water layer (39) and a deep geothermal water layer (42) are separated by using a sand control packer according to any one of claims 1 to 9, and the shallow geothermal water layer (39) and the deep geothermal water layer (42) are mined respectively.

11. A layered irrigation process, characterized in that: A sand control packer according to any one of claims 1 to 9 is used to separate a shallow geothermal water layer (39) from a deep geothermal water layer (42), the deep geothermal water layer (42) is mined, and the used geothermal water is recharged into the shallow geothermal water layer (39).

12. A layered irrigation process, characterized in that: A sand control packer according to any one of claims 1 to 9 is used to separate a shallow geothermal water layer (39) from a deep geothermal water layer (42), and used deep geothermal water is reinjected into the deep geothermal water layer (42), and used shallow geothermal water is reinjected into the shallow geothermal water layer (39).

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