Horizontal well efficient rotational flow grinding and milling sand washing device and sand washing method

Abstract

The invention discloses a horizontal well efficient rotational flow grinding and milling sand washing device which comprises an outer spiral sand washing device body, an inner spiral sand washing device body, a core pipe, an upper connector and a core shaft, the outer spiral sand washing device body is provided with an axial nozzle, an axial nozzle pressing cap and a spiral flow guide groove a, and the inner spiral sand washing device body is provided with a spiral flow guide groove b. The spiral-flow sand washing tool has the tangential washing function of the spiral-flow sand washing tool and the grinding and milling function of the screw power drilling tool. The invention further discloses a horizontal well efficient rotational flow grinding and milling sand washing method which specifically comprises the steps that the sand washing device is assembled, the sand washing pipe column is connected, the sand washing pipe column is put down in the casing pipe, the underground sand scale position is explored, a wellhead oil pipe is connected with a sand washing pump truck, and a pump is started to conduct sand washing and grinding operation. Sand washing liquid enters the inner cavity of the core pipe from the inner cavity of the upper joint of the sand washing device through the centralizer from the oil pipe and then provides three-stage forward rotation power for the sand washing device, and rotary milling power is provided for the sand washing device, so that sand washing is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploration and development, relates to a high-efficiency cyclone milling sand flushing device for a horizontal well, and also relates to a high-efficiency cyclone milling sand flushing method for a horizontal well. Background Art

[0002] After a period of production, oil, gas and water wells may have problems such as sanding and scaling in the wellbore, blockage of perforation holes and wellbore bridge blockage. Wellbore cleaning and treatment measures such as scale block milling and sand flushing must be carried out. Existing sand flushing tools are relatively simple. The simplest one is the oblique tip, which can only achieve the purpose of using the well washing fluid to bring the gravel out of the wellbore, but cannot deal with the problems of wellbore scaling and perforation hole blockage. At present, the more advanced sand flushing tool is a sand flusher with a jet nozzle, which converts the pressure potential energy into high-speed jet kinetic energy. The sand flushing head is designed with nozzles in multiple directions to flush sand and scale at different angles, especially the lateral nozzle, which has a significant cleaning and unblocking effect on the well wall and perforation holes, and can impact and break relatively loose scale blocks and cementing materials, but cannot break up stubborn cementing scaling. In order to remove stubborn scale in the wellbore, the existing method is to use a screw to provide rotational power to drive the drill bit or milling cone for grinding. This method can effectively remove stubborn scale in the wellbore, but the cleaning and trimming effect on the well wall and the flushing and unblocking effect on the perforation holes on the casing are not obvious. For horizontal well sand flushing and descaling, if a screw is used to provide rotational power, since the screw is relatively long, the passability is poor, and the risk of drill sticking is greater, it is necessary to develop a sand flushing and milling tool that can provide its own rotational power. Summary of the invention

[0003] The purpose of the invention is to provide a high-efficiency cyclone milling sand flushing device for horizontal wells, which solves the problems that conventional sand flushing tools have no rotary milling function, screw drilling tool sand flushing has no cyclone jet effect, and the sand flushing and descaling effect is not ideal.

[0004] The purpose of the invention is to provide a high-efficiency cyclone milling sand flushing method for a horizontal well, thereby improving the milling sand flushing efficiency.

[0005] The first technical solution adopted by the present invention is a high-efficiency cyclone milling sand flusher for horizontal wells, comprising an outer spiral sand flusher body, an end face of one end of the outer spiral sand flusher body is provided with an axial nozzle and an axial nozzle pressure cap, the outer spiral sand flusher body is in a hollow cylindrical shape, and the end head of the outer spiral sand flusher body at one end of which the axial nozzle is provided is in a truncated cone shape, a spiral guide groove a is provided on the cylindrical surface of the outer spiral sand flusher body, and a core tube is connected to the other end, one end of the core tube is inserted into the outer spiral sand flusher body, and the part of the core tube located at the outer spiral sand flusher body is connected to an upper joint, an inner spiral sand flusher body is provided in the outer spiral sand flusher body, the inner spiral sand flusher body is in a hollow cylindrical shape, a spiral guide groove b is provided on the cylindrical surface of the inner spiral sand flusher body, and a core shaft is provided in the inner spiral sand flusher body, and the core shaft is connected to the end head of the core tube extending into the outer spiral sand flusher body.

[0006] The first technical solution of the present invention is also characterized in that:

[0007] The outer spiral sand scouring device body is a right-hand spiral tooth, the inner spiral sand scouring device body is a left-hand spiral tooth, and a side through hole is provided on a side wall of one end of the inner spiral sand scouring device body close to the end of the outer spiral sand scouring device body.

[0008] Two axial nozzles are provided, each of which is provided with an axial nozzle pressure cap. The two axial nozzles are centrally symmetrically arranged on the end face of the outer spiral sandblasting device body, and the end face of the outer spiral sandblasting device body provided with the axial nozzle is also provided with four radial diversion grooves, and the outlet of each axial nozzle pressure cap is connected to the two diversion grooves. Four right-angle guide grooves are evenly distributed on the outside of the truncated cone-shaped end of the outer spiral sandblasting device body, and the right-angle guide grooves are connected and communicated with the diversion grooves one by one. Four spiral guide grooves a are also provided, and the spiral guide grooves a are connected and communicated with the right-angle guide grooves at the large diameter of the truncated cone of the outer spiral sandblasting device body.

[0009] Four axial holes are arranged inside the external spiral sand blasting machine body, and each right-angle guide groove is provided with a lateral nozzle and a corresponding lateral nozzle pressure cap. The inner hole of the lateral nozzle is connected and communicated with the axial hole of the external spiral sand blasting machine body in a one-to-one correspondence. The axial direction of the lateral nozzle is a composite angle of an axial angle of 60° and a radial angle of 60°.

[0010] A sealing ring a is arranged on the axial nozzle, and the sealing ring a is arranged between the axial nozzle and the outer spiral sand blasting device body. The axial nozzle pressing cap is pressed on the outer end surface of the axial nozzle, and the axial nozzle pressing cap is connected to the outer spiral sand blasting device body through threads.

[0011] The outer surface of the external spiral sandblasting device body is welded with a hard alloy grinding layer.

[0012] The outer edge of the spiral teeth of the inner spiral sand washing machine body is tightly matched with the inner wall of the outer spiral sand washing machine body, and the matching surface of the spiral teeth of the inner spiral sand washing machine body and the inner wall of the outer spiral sand washing machine body is provided with sealant, and the connection between the outer spiral sand washing machine body and the core tube is provided with an anti-slip ring, and the outer spiral sand washing machine body is connected to the anti-slip ring through a thread.

[0013] Two bearings are arranged between the core shaft and the inner spiral sandblasting device body, and the two bearings are respectively close to the two ends of the core shaft, the inner ring of the bearing is matched with the outer circle of the core shaft, and the outer ring of the bearing is matched with the inner hole of the inner spiral sandblasting device body. An adjusting ring is arranged on the core shaft, and the connecting end of the inner spiral sandblasting device body and the core tube is connected to the adjusting ring through a thread, and the end face of one side of the adjusting ring is pressed against the end face of the outer ring of the bearing, and the flange of the other side end face is provided with a top screw, and the top screw is pressed in the positioning groove provided on the inner spiral sandblasting device body.

[0014] The core shaft is provided with a sealing ring b, which is located between the core shaft and the inner wall of the inner spiral sand blasting device body. The outer circle of the core tube is provided with a dustproof ring, which cooperates with the inner hole of the adjustment ring, and an axial gap is provided between the core tube and the adjustment ring. A square hole is provided on the side wall of the connecting end of the core tube and the inner spiral sand blasting device body.

[0015] The core tube is connected to the upper joint through threads, a sealing ring c is arranged on the outer circle in the middle of the core tube, the sealing ring c is located between the core tube and the inner wall of the outer spiral sand washing device body, a sealing ring d is arranged in the middle of the inner hole of the upper joint, the sealing ring d is located between the upper joint and the outer circle on the right side of the core tube, and a friction ring is arranged at the root of the thread connecting the upper joint and the core tube.

[0016] The second technical solution adopted by the present invention is a horizontal well high-efficiency cyclone grinding and milling sand flushing method, which uses a horizontal well high-efficiency cyclone grinding and milling sand flushing device such as the present invention to perform sand flushing. Specifically, the sand flushing device is assembled, a sand flushing pipe string is connected, the sand flushing pipe string is lowered into the casing, the location of sand scale downhole is explored, the wellhead oil pipe is connected to the sand flushing pump truck, and the pump is turned on to perform sand flushing and milling operations. The sand flushing fluid flows from the oil pipe through the centralizer and from the inner cavity of the upper joint of the sand flushing device into the inner cavity of the core tube, providing three-level positive rotation power for the sand flushing device, providing rotational grinding power for the sand flushing device, and realizing sand flushing.

[0017] The second technical solution of the present invention is also characterized in that:

[0018] Follow the steps below to implement it:

[0019] Step 1: Assemble the sandblaster and select the nozzle size according to the sandblasting construction displacement. In order to ensure sufficient jet impact effect without damaging the casing, the jet speed is controlled at 60-100m / s;

[0020] Step 2, connecting the sand flushing pipe column, the structure of the sand flushing pipe column is composed of a sand flusher, a centralizer, and an oil pipe from bottom to top, and the centralizer, the sand flusher, and the oil pipe are all connected through oil pipe threads;

[0021] Step 3: Run a sand flushing string into the casing, slowly lower the string, and explore the location of sand and scale in the well;

[0022] Step 4: After sand scale is detected, lift the pipe column by 0.3-0.5 meters, connect the wellhead oil pipe to the sand flushing pump truck, set the sand flushing displacement, and start the pump to perform sand flushing and milling operations;

[0023] Step 5, the sand flushing liquid passes through the centralizer from the oil pipe and enters the inner cavity of the core tube from the inner cavity of the upper joint of the sand flushing device, and flows out from the square hole opened at the connecting end of the core tube and the inner spiral sand flushing device body, impacting the spiral teeth of the inner spiral sand flushing device body. The inner spiral sand flushing device body is a right-hand spiral, and the fluid generates a positive rotation torque on the inner spiral, that is, the tightening direction of the core shaft thread, providing the first-level rotation power of the sand flushing device;

[0024] Step 6, after the sand washing liquid comes out from the left side of the inner spiral sand washing machine body, 1 / 3 of it enters through the side through hole of the inner spiral sand washing machine body, and is sprayed out from the axial nozzle of the outer spiral sand washing machine body to impact the sand bridge in front, and 2 / 3 of the sand washing liquid enters through the axial hole of the outer spiral sand washing machine body, and is sprayed out from the four lateral nozzles of the outer spiral sand washing machine body, which generates both a spray force to the side and front and a circumferential tangential spray force. The reaction of the circumferential tangential spray generates a positive rotation torque on the outer spiral, providing the second-level rotation power of the sand washing machine;

[0025] Step 7, the fluid sprayed from the axial nozzle of the external spiral sand washer body returns from the diversion groove, flows through the right-angle guide groove, and returns from the spiral guide groove a on the cylindrical surface of the external spiral sand washer body together with the fluid returned from the corresponding lateral nozzle, and returns to the ground through the annulus of the oil pipe and casing. The external spiral sand washer body is a left-hand spiral, and the fluid flowing through the spiral guide groove b generates a positive rotation torque to the external spiral sand washer body, providing the third-level rotation power of the sand washer;

[0026] The three-stage positive rotation power provides sufficient rotational milling power for the sand flusher to remove the stubborn scale and stone on the inner wall of the casing, flush and unblock the perforation hole blockage on the casing, break the stubborn scale and stone in the milling casing, and realize sand flushing.

[0027] The beneficial effects of the present invention are:

[0028] 1) The high-efficiency cyclone sand-grinding and milling device for horizontal wells of the present invention can generate rotational power autonomously, and has both the tangential flushing function of the cyclone sand-grinding tool and the milling function of the screw power drilling tool.

[0029] 2) The lateral nozzle of the sand flusher of the present invention is conducive to the stripping of scale blocks on the inner wall of the casing, and avoids the positive impact on the inner wall of the casing, thereby reducing the damage to the casing, and can remove the stubborn scale and stone on the inner wall of the casing, and has a significant flushing and unblocking effect on the perforation hole blockage on the casing, which is conducive to clearing the perforation hole.

[0030] 3) The left end face, conical surface and left side of the outer cylindrical surface of the sand flusher of the present invention are all welded with a hard alloy grinding layer, which is used to grind the stubborn scale in the casing. When the sand flusher rotates, the grinding layer has a breaking and stripping effect on the stubborn scale, and has a grinding and refining effect on the larger scale, which is conducive to the sand flushing fluid carrying it back out of the wellbore.

[0031] 4) Two thrust bearings are installed between the core shaft and the inner spiral of the sandblaster to bear the forces at the left and right ends of the core shaft, which can greatly reduce the rotational resistance of the rotating parts of the sandblaster.

[0032] 5) The inner spiral positioning groove, adjustment ring, top screw and core tube of the sandblaster are interlocked and locked in sequence to ensure the axial positioning of the two bearings.

[0033] 6) The spiral assembly, anti-slip ring and upper joint of the sand flusher are interlocked and locked in sequence to ensure that the anti-slip ring provides overload protection for the spiral assembly to prevent the drill from getting stuck or unstuck, eliminating the risk of the rotating parts of the sand flusher falling into the well.

[0034] 7) The centralizer is an elastic centralizer with free bidirectional traction on both ends. No matter lifting or lowering the sand flushing pipe column, the spring leaf of the centralizer is pulled and tensile deformed. Compared with the traditional elastic centralizer, the spring leaf is prone to bending deformation due to the pushing effect, avoiding the risk of spring leaf wrinkling and drill jamming.

[0035] 8) The sandblaster has three levels of rotational power, which can generate sufficient grinding and milling rotational power, and the triple rotational torque is conducive to the tightening of the positive thread, reducing the risk of tool disengagement.

[0036] 9) The left end face, conical surface and outer circumferential surface of the outer spiral of the sand flusher are all provided with guide grooves. The outer edges of the guide grooves are sharp and can produce a scraping effect, especially the guide grooves on the outer circumferential surface can scrape and trim the inner wall of the casing.

[0037] 10) The inner diameter of the wellbore formed by the sand flusher is small, and the bottoming effect of the pipe string will increase the rotational resistance of the sand flusher milling. The innovatively designed two-way traction elastic centralizer has a good centering effect, which can reduce the friction of the pipe string bottoming and ensure the output efficiency of the sand flusher's rotational power.

[0038] 11) The right end of the outer spiral of the sand flusher is connected with an anti-slip ring. If the sand flusher is stuck when lifting the pipe string, the anti-slip ring can prevent the rotating parts of the sand flusher from falling off, avoiding fish falling accidents in the well.

[0039] 12) The high-efficiency cyclone milling sand flushing method for horizontal wells of the present invention uses the high-efficiency cyclone milling sand flushing device for horizontal wells of the present invention to perform sand flushing, which can autonomously generate three-level rotational power, remove stubborn scale and stone on the inner wall of the casing, flush and unblock the perforation hole blockage on the casing, and break the stubborn scale and stone in the milling casing, with a significant sand flushing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of a high-efficiency cyclone milling sand flushing device for horizontal wells according to the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of the outer spiral sand washer body of the horizontal well high-efficiency cyclone milling sand washer of the present invention, wherein: Figure 2 (a) is the main view of the external spiral sandblasting machine. Figure 2 (b) is a side view of the external spiral sand washing device body;

[0042] Figure 3 This is a schematic diagram of the structure of the inner spiral sand washer body of the high-efficiency cyclone milling sand washer for horizontal wells of the present invention, wherein: Figure 3 (a) is the side view of the inner spiral sandblasting device body. Figure 3(b) is a front view of the inner spiral sand washing device body;

[0043] Figure 4 This is a schematic diagram of a milling and sand-blasting pipe column;

[0044] Figure 5 It is a working principle diagram of the high-efficiency cyclone milling sand flushing device for horizontal wells of the present invention.

[0045] In the figure, 1. axial nozzle pressing cap, 2. axial nozzle, 3. sealing ring a, 4. axial hole, 5. sealing ring b, 6. bearing, 7. outer spiral sandblasting device body, 8. inner spiral sandblasting device body, 9. core shaft, 10. dust ring, 11. adjustment ring, 12. top screw, 13. small hexagonal hole, 14. square hole, 15. sealing ring c, 16. anti-slip ring, 17. core tube, 18. friction ring, 19. sealing ring d, 20. large hexagonal hole, 21. upper joint, 22. diverter groove, 23. right-angle guide groove, 24. spiral guide groove a, 25. grinding layer, 26. side through hole, 27. spiral guide groove b, 28. positioning groove, 29. oil pipe, 30. casing, 31. centralizer, 32. sandblasting device, 33. sand scale, 34. lateral nozzle, 35. lateral nozzle pressing cap. DETAILED DESCRIPTION

[0046] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Example 1

[0048] This embodiment provides a high-efficiency cyclone milling sand flushing device for horizontal wells, such as Figure 1 As shown, it includes an outer spiral sand washing device body 7, such as Figure 2 As shown, the outer spiral sandblasting device body 7 is a right-hand spiral tooth, and an axial nozzle 2 and an axial nozzle pressure cap 1 are arranged on the end face of one end of the outer spiral sandblasting device body 7. The axis of the axial nozzle 2 is parallel to the axial direction of the outer spiral sandblasting device body 7. The outer spiral sandblasting device body 7 is a hollow cylindrical shape, and the end of the outer spiral sandblasting device body 7 provided with the axial nozzle 2 is in the shape of a truncated cone. The cylindrical surface of the outer spiral sandblasting device body 7 is provided with a spiral guide groove a24, and the notch of the spiral guide groove a24 has sharp edges and corners. When the sandblasting device rotates, it has a scraping and trimming effect on the inner wall of the casing. The other end is connected with a core tube 17, and one end of the core tube 17 is inserted into the outer spiral sandblasting device body 7. The part of the core tube 17 located at the outer spiral sandblasting device body 7 is connected with an upper joint 21. An inner spiral sandblasting device body 8 is arranged in the outer spiral sandblasting device body 7, as shown in FIG. Figure 3As shown, the inner spiral sand flushing machine body 8 is a hollow cylindrical shape, the inner spiral sand flushing machine body 8 is a left-hand spiral tooth, a side through hole 26 is opened on the side wall of the inner spiral sand flushing machine body 8 near the end of the outer spiral sand flushing machine body 7, a spiral guide groove b27 is arranged on the cylindrical surface of the inner spiral sand flushing machine body 8, a core shaft 9 is arranged in the inner spiral sand flushing machine body 8, and the core shaft 9 is connected to the end of the core tube 17 extending into the outer spiral sand flushing machine body 7.

[0049] Example 2

[0050] The present embodiment provides a high-efficiency cyclone milling sand flusher for horizontal wells. On the basis of embodiment 1, two axial nozzles 2 are provided, each of which is provided with an axial nozzle pressure cap 1, and the two axial nozzles 2 are centrally symmetrically arranged on the end face of the outer spiral sand flusher body 7. The axial nozzle 2 produces a frontal jet with a strong impact effect, which can achieve the effect of breaking through the center of the sand bridge, and the end face of the outer spiral sand flusher body 7 provided with the axial nozzle 2 is also provided with four radial diversion grooves 22, and the outlet of each axial nozzle pressure cap 1 is connected to the two diversion grooves 22. Four right-angle guide grooves 23 are evenly distributed on the outside of the truncated cone-shaped end of the outer spiral sand flusher body 7, and the right-angle guide grooves 23 are connected and communicated with the diversion grooves 22 in a one-to-one correspondence. Four spiral guide grooves a24 are also provided, and the spiral guide grooves a24 are connected and communicated with the right-angle guide grooves 23 in a one-to-one correspondence at the large diameter of the truncated cone of the outer spiral sand flusher body 7.

[0051] Example 3

[0052] The present embodiment provides a high-efficiency cyclone milling sand flusher for horizontal wells. On the basis of the embodiments 1-2, four axial holes 4 are arranged inside the outer spiral sand flusher body 7, and each right-angle guide groove 23 is provided with a lateral nozzle 34 and a corresponding lateral nozzle pressure cap 35. The lateral nozzle 34 avoids the frontal impact on the casing and reduces the damage to the casing. The tangential impact formed by the lateral nozzle 34 can produce a stripping effect, which can remove the stubborn scale and stone on the inner wall of the casing, and has a significant flushing and unblocking effect on the perforation hole blockage on the casing. The inner hole of the lateral nozzle 34 is connected and communicated with the axial hole 4 of the outer spiral sand flusher body 7 in a one-to-one correspondence. The axial direction of the lateral nozzle 34 is a composite angle of its axial angle of 60° and radial angle of 60°, that is, the axis rotates 60° to the left as the positive direction, and then rotates 60° counterclockwise facing the left end face;

[0053] A sealing ring a3 is provided on the axial nozzle 2, and the sealing ring a3 is provided between the axial nozzle 2 and the external spiral sandblasting device body 7. The axial nozzle pressing cap 1 is pressed on the outer end surface of the axial nozzle 2, and the axial nozzle pressing cap 1 is connected to the external spiral sandblasting device body 7 through threads. The axial nozzle pressing cap 1 is pressed tightly on the outer end surface of the axial nozzle 2, and the inner hole of the axial nozzle pressing cap 1 is a hexagonal hole, which not only makes way for the jet channel of the axial nozzle 2, but also facilitates the installation and tightening of the axial nozzle pressing cap 1.

[0054] The outer surface of the outer spiral sandblasting device body 7 is welded with a hard alloy grinding layer 25. When the sandblasting device rotates, the grinding layer 25 has a cutting and grinding effect on stubborn scale and a grinding and refining effect on larger scale blocks, and is used to grind stubborn scale in the casing.

[0055] Example 4

[0056] The present embodiment provides a high-efficiency cyclone milling sand flusher for horizontal wells. On the basis of embodiments 1-3, the outer edge of the spiral teeth of the inner spiral sand flusher body 8 is tightly matched with the inner wall of the outer spiral sand flusher body 7, and the mating surfaces of the spiral teeth of the inner spiral sand flusher body 8 and the inner wall of the outer spiral sand flusher body 7 are provided with sealant, and the right end of the spiral teeth of the inner spiral sand flusher body 8 (the connecting end with the core tube 17) is welded to the inner hole of the outer spiral sand flusher body 7 to form a spiral assembly.

[0057] An anti-slip ring 16 is provided at the connection between the outer spiral sand blasting device body 7 and the core tube 17, and the outer spiral sand blasting device body 7 and the anti-slip ring are connected by threads. The anti-slip ring 16 and the core tube 17 and the upper joint 21 all have axial clearances to ensure that the outer spiral sand blasting device body 7 can rotate freely with the anti-slip ring 16. The inner hole of the connecting end of the core tube 17 and the upper joint is a large hexagonal hole 20, which is convenient for placing a hexagonal wrench when assembling the core tube 17. The inner hole of the connecting end of the core shaft 9 and the core tube 17 is a small hexagonal hole 13.

[0058] Example 5

[0059] The present embodiment provides a high-efficiency cyclone milling sand flusher for horizontal wells. On the basis of embodiments 1-4, two bearings 6 are arranged between the core shaft 9 and the inner spiral sand flusher body 8, and the two bearings are respectively close to the two ends of the core shaft 9. The inner ring of the bearing 6 is matched with the outer circle of the core shaft 9, and the outer ring of the bearing 6 is matched with the inner hole of the inner spiral sand flusher body 8. The core shaft positions the inner ring of the bearing through its outer circle step, and the inner spiral sand flusher body 8 positions the outer ring of the bearing through its outer circle step. An adjusting ring 11 is arranged on the core shaft 9, and the connecting end of the inner spiral sand flusher body 8 and the core tube 17 is connected to the adjusting ring 11 through a thread. The end face of one side of the adjusting ring 11 presses against the end face of the outer ring of a bearing. The axial fitting tightness of the two bearings 6 can be adjusted by adjusting the screw-in depth of the adjusting ring 11. The flange of the other end face is provided with a top screw 12, and the top screw 12 presses in the positioning groove 28 provided in the inner spiral sand flusher body 8 to prevent the adjusting ring 11 from loosening, so as to avoid circumferential displacement relative to the inner spiral 8 and affect the fitting tightness of the two bearings 6.

[0060] The mandrel is provided with a sealing ring b5 and a dust ring 10, and the dust ring 10 cooperates with the inner hole of the adjusting ring 11 to prevent solid impurities from invading the left cavity and affecting the operation of the two bearings 6. The sealing ring b5 is located between the mandrel 9 and the inner wall of the inner spiral sand blasting device body 8. The outer circle of the core tube 17 is provided with a dust ring 10, and the dust ring 10 cooperates with the inner hole of the adjusting ring 11, and the core tube 17 and the adjusting ring 11 are provided with an axial gap to ensure that the adjusting ring 11 rotates flexibly with the spiral assembly. This axial gap needs to be smaller than the depth of the positioning groove 28 of the inner spiral sand blasting device body 8 to limit the loosening and retreat of the top screw 12 so as not to be disengaged from the positioning groove 28, thereby ensuring that the adjusting ring 11 is reliably positioned. The positioning groove 28 of the inner spiral sand blasting device body 8, the adjusting ring 11, the top screw 12, and the core tube 17 are interlocked and locked with each other to ensure the axial positioning of the two bearings 6;

[0061] A square hole 14 is provided on the side wall of the connecting end of the core tube 17 and the inner spiral sand blasting device body 8. The core tube 17 is connected to the upper joint 21 by threads. There are multiple square holes 14 evenly distributed on the middle tube wall of the core tube 17. The long side of the hole is along the axial direction, which can increase the flow area and reduce the flow resistance under the premise of ensuring strength. A sealing ring c15 is provided on the outer circle of the middle part of the core tube 17. The sealing ring c15 is located between the core tube 17 and the inner wall of the outer spiral sand blasting device body 7. A sealing ring d19 is provided in the middle of the inner hole of the upper joint 21. The sealing ring d19 is located between the upper joint 21 and the outer circle on the right side of the core tube 17. A friction ring 18 is provided at the root of the thread connecting the upper joint 21 and the core tube 17 to increase the friction force of the threaded connection between the core tube 17 and the upper joint 21 and enhance the anti-loosening effect.

[0062] Example 6

[0063] The present embodiment provides a method for high-efficiency cyclone grinding and sand flushing of horizontal wells, which uses any high-efficiency cyclone grinding and sand flushing device for horizontal wells of Embodiments 1-4 to perform sand flushing. Specifically, the sand flushing device is assembled, a sand flushing pipe string is connected, the sand flushing pipe string is lowered into the casing, the location of sand scale downhole is explored, the wellhead oil pipe is connected to the sand flushing pump truck, and the pump is turned on to perform sand flushing and grinding operations. The sand flushing fluid flows from the oil pipe through the centralizer and from the inner cavity of the upper joint of the sand flushing device into the inner cavity of the core tube 17, and then provides three-level positive rotation power for the sand flushing device, and provides rotational grinding power for the sand flushing device to achieve sand flushing.

[0064] Example 7

[0065] This embodiment provides a horizontal well high-efficiency cyclone milling sand flushing method, which is implemented based on Example 6 in the following steps:

[0066] Step 1) Assemble the sandblaster and select the nozzle size according to the sandblasting construction displacement. In order to ensure sufficient jet impact effect without damaging the casing, the jet speed is controlled at 60-100m / s. Therefore, for 0.6-1.0m 3 / min displacement, it is recommended to install 6 6mm nozzles, for 1.1-1.8m 3 / min displacement, install 6 8mm nozzles;

[0067] Step 2) Figure 4 As shown, the sand flushing pipe string is connected, and the structure of the sand flushing pipe string is composed of a sand flushing device 32, a centralizer 31, and an oil pipe 29 from bottom to top. The centralizer 31 is connected to the sand flushing device 32 and the oil pipe 29 through the oil pipe 29 thread;

[0068] Step 3) inserting a sand flushing string into the casing 30, and slowly lowering the string to explore the location of the sand scale 33 downhole;

[0069] Step 4) After sand scale is detected, lift the pipe column 0.3-0.5 meters, connect the wellhead oil pipe to the sand flushing pump truck, set the sand flushing displacement, start the pump to perform sand flushing and milling operations. The sand flushing displacement refers to the size of the nozzle. The displacement range of 6 6mm nozzles is 0.6-1.0m 3 / min; 6 8mm nozzles, displacement range 1.1-1.8m 3 / min;

[0070] Step 5: Figure 5 As shown, the sand flushing fluid enters the inner cavity of the core tube 17 from the inner cavity of the joint 21 of the sand flushing device 32 through the oil pipe, flows out from the square hole 14 opened at the connection end between the core tube 17 and the inner spiral sand flushing device body 8, and impacts the spiral teeth of the inner spiral sand flushing device body 8. The inner spiral sand flushing device body 8 is a right-hand spiral. The fluid generates a positive rotation torque on the inner spiral, that is, the tightening direction of the core shaft thread, providing the first-level rotation power of the sand flushing device.

[0071] Step 6, after the sand washing liquid comes out from the left side of the inner spiral sand washing machine body 8, 1 / 3 of the sand washing liquid enters through the side through hole 26 of the inner spiral sand washing machine body 8, and is sprayed out from the axial nozzle 2 of the outer spiral sand washing machine body 7 to impact the sand bridge in front, and 2 / 3 of the sand washing liquid enters through the axial hole 4 of the outer spiral sand washing machine body 7, and is sprayed out from the four lateral nozzles 34 of the outer spiral sand washing machine body 7, which generates both a spray force to the side and front and a circumferential tangential spray force. The reaction of the circumferential tangential spray generates a positive rotation torque on the outer spiral, providing the second-stage rotation power of the sand washing machine;

[0072] Step 7, the fluid sprayed from the axial nozzle 2 of the outer spiral sand washer body 7 returns from the diverter groove 22, flows through the right-angle guide groove 23, and returns from the spiral guide groove a24 on the cylindrical surface of the outer spiral sand washer body 7 together with the fluid returned from the corresponding lateral nozzle 34, and returns to the ground through the annulus of the oil pipe 29 and the casing 30. The outer spiral sand washer body 7 is a left-hand spiral, and the fluid flowing through the spiral guide groove b27 generates a positive rotation torque to the outer spiral sand washer body 7, providing the third-level rotation power of the sand washer;

[0073] The three-stage positive rotation power provides sufficient rotational milling power for the sand flusher to remove stubborn scale and stone on the inner wall of the casing 30, flush and unblock the perforation hole blockage on the casing 30, break the stubborn scale and stone in the milling casing, and realize sand flushing.

[0074] The sand flushing process of the high-efficiency cyclone milling sand flushing method for horizontal wells in this embodiment has the following advantages:

[0075] The axial nozzle 2 produces a frontal jet with a strong impact, which can achieve the effect of breaking through the center of the sand scale 33. The lateral nozzle 34 avoids the frontal impact on the casing 30 and reduces the risk of damage to the casing 30. The tangential impact formed by the lateral nozzle can produce a cutting and stripping effect on the scale on the inner wall of the casing 30, which can remove the stubborn scale on the inner wall of the casing 30 and has a significant flushing and unblocking effect on the perforation hole blockage on the casing.

[0076] The connecting threads between the core shaft 9 and the core tube 17, the connecting threads between the core tube 17 and the upper joint 21, the connecting threads between the upper joint 21 and the centralizer 31, and the connecting threads of all the oil pipes 29 are all positive threads. The three-level positive rotation power has a tightening effect on the positive threads, reducing the risk of loosening and disengagement of the pipe string threads.

[0077] The outer spiral 7 and the inner spiral 8 are partially welded. The bearing 6, the adjusting ring 11 and the welding part are the weak points of the tensile strength of the sand flusher. If the sand flusher is stuck, the upward unblocking force may cause these weak points to fail. Then the anti-slip ring 16 will hang on the outer step of the core tube 17 to prevent the sand flusher from falling off, thereby avoiding fish falling accidents in the well.

[0078] The connecting thread of the outer spiral 7 and the anti-slip ring 16 is also a positive thread, and the rotation of the outer spiral 7 also produces a tightening effect on the thread, reducing the risk of loosening of the anti-slip ring 16. The axial clearance between the anti-slip ring 16 and the upper joint 21 is small. In case the anti-slip ring 16 is loosened and moved to the right, the left end surface of the upper joint 21 will prevent the anti-slip ring 16 from loosening, and the friction on the anti-slip ring 16 can cause the anti-slip ring 16 to tighten and move to the left.

[0079] The inner diameter of the wellbore after grinding is small, and the bottoming effect of the pipe string will increase the rotational resistance of the sand flusher. The innovatively designed two-way traction elastic centralizer has a good centering effect, which can reduce the friction of the pipe string bottoming and ensure the output efficiency of the sand flusher's rotational power.

Claims

1. High-efficiency cyclone milling sand flushing device for horizontal wells, characterized by: The invention comprises an external spiral sand blasting device body (7), one end surface of which is provided with an axial nozzle (2) and an axial nozzle pressing cap (1), the external spiral sand blasting device body (7) is in the shape of a hollow cylinder, and the end of the external spiral sand blasting device body (7) provided with the axial nozzle (2) is in the shape of a truncated cone, the cylindrical surface of the external spiral sand blasting device body (7) is provided with a spiral guide groove a (24), and the other end is connected to a core tube (17), one end of which is inserted into the external spiral sand blasting device body ( 7), the core tube (17) is located in the part of the outer spiral sand scouring device body (7) and is connected to an upper joint (21), an inner spiral sand scouring device body (8) is arranged in the outer spiral sand scouring device body (7), the inner spiral sand scouring device body (8) is in the shape of a hollow cylinder, a spiral guide groove b (27) is arranged on the cylindrical surface of the inner spiral sand scouring device body (8), a core shaft (9) is arranged in the inner spiral sand scouring device body (8), and the core shaft (9) is connected to the end of the core tube (17) extending into the outer spiral sand scouring device body (7).

2. The high-efficiency cyclone milling sand flushing device for horizontal wells according to claim 1 is characterized in that: The outer spiral sand blasting device body (7) is a right-hand spiral tooth, and the inner spiral sand blasting device body (8) is a left-hand spiral tooth. A side through hole (26) is provided on a side wall of one end of the inner spiral sand blasting device body (8) close to the end of the outer spiral sand blasting device body (7).

3. The high-efficiency cyclone milling sand flushing device for horizontal wells according to claim 1 is characterized in that: Two axial nozzles (2) are provided, each axial nozzle (2) is provided with an axial nozzle pressing cap (1), the two axial nozzles (2) are centrally symmetrically arranged on the end face of the external spiral sandblasting device body (7), and the end face of the external spiral sandblasting device body (7) provided with the axial nozzles (2) is also provided with four radial diversion grooves (22), each outlet of the axial nozzle pressing cap (1) is connected to the two diversion grooves (22), four right-angle guide grooves (23) are evenly distributed on the outer side of the truncated cone-shaped end of the external spiral sandblasting device body (7), the right-angle guide grooves (23) are connected and communicated with the diversion grooves (22) in a one-to-one correspondence, and four spiral guide grooves a (24) are also provided, and the spiral guide grooves a (24) are connected and communicated with the right-angle guide grooves (23) in a one-to-one correspondence at the large diameter of the truncated cone of the external spiral sandblasting device body (7).

4. The high-efficiency cyclone milling sand flushing device for horizontal wells according to claim 1, characterized in that: Four axial holes (4) are arranged inside the external spiral sand scouring device body (7), and each of the right-angle guide grooves (23) is provided with a lateral nozzle (34) and a corresponding lateral nozzle pressing cap (35), the inner hole of the lateral nozzle (34) is connected and communicated with the axial hole (4) of the external spiral sand scouring device body (7) in a one-to-one correspondence, and the axial direction of the lateral nozzle (34) is a composite angle of an axial angle of 60° and a radial angle of 60°; The axial nozzle (2) is provided with a sealing ring a (3), the sealing ring a (3) is arranged between the axial nozzle (2) and the external spiral sandblasting device body (7), the axial nozzle pressing cap (1) is pressed on the outer end surface of the axial nozzle (2), and the axial nozzle pressing cap (1) and the external spiral sandblasting device body (7) are connected via threads.

5. The high-efficiency cyclone milling sand flushing device for horizontal wells according to claim 3 is characterized in that: A hard alloy grinding layer (25) is welded on the outer surface of the outer spiral sandblasting device body (7).

6. The high-efficiency cyclone milling sand flushing device for horizontal wells according to claim 1, characterized in that: The outer edge of the spiral teeth of the inner spiral sand scouring device body (8) is tightly matched with the inner wall of the outer spiral sand scouring device body (7), and the matching surfaces of the spiral teeth of the inner spiral sand scouring device body (8) and the inner wall of the outer spiral sand scouring device body (7) are provided with sealant, and the connection between the outer spiral sand scouring device body (7) and the core tube (17) is provided with an anti-slip ring (16), and the outer spiral sand scouring device body (7) and the anti-slip ring are connected by threads.

7. The high-efficiency cyclone milling sand flushing device for horizontal wells according to claim 6, characterized in that: Two bearings (6) are arranged between the core shaft (9) and the inner spiral sandblasting device body (8), and the two bearings are respectively close to the two ends of the core shaft (9). The inner ring of the bearing (6) is matched with the outer circle of the core shaft (9), and the outer ring of the bearing (6) is matched with the inner hole of the inner spiral sandblasting device body (8). An adjustment ring (11) is arranged on the core shaft (9), and the connecting end of the inner spiral sandblasting device body (8) and the core tube (17) is connected to the adjustment ring (11) through a thread. The end face of one side of the adjustment ring (11) is pressed against the end face of the outer ring of a bearing, and the flange of the other side end face is provided with a top screw (12), and the top screw (12) is pressed in a positioning groove (28) provided in the inner spiral sandblasting device body (8).

8. The high-efficiency cyclone milling sand flushing device for horizontal wells according to claim 1, characterized in that: The core shaft is provided with a sealing ring b (5), and the sealing ring b (5) is located between the core shaft (9) and the inner wall of the inner spiral sand blasting device body (8); the outer circle of the core tube (17) is provided with a dust ring (10), and the dust ring (10) is matched with the inner hole of the adjustment ring (11), and an axial gap is provided between the core tube (17) and the adjustment ring (11); and a square hole (14) is provided on the side wall of the connection end between the core tube (17) and the inner spiral sand blasting device body (8); The core tube (17) and the upper joint (21) are connected by threads; a sealing ring c (15) is provided on the outer circle of the middle part of the core tube (17); the sealing ring c (15) is located between the core tube (17) and the inner wall of the outer spiral sand washing device body (7); a sealing ring d (19) is provided on the middle part of the inner hole of the upper joint (21); the sealing ring d (19) is located between the upper joint (21) and the outer circle of the right side of the core tube (17); and a friction ring (18) is provided on the root of the thread connecting the upper joint (21) and the core tube (17).

9. A method for high-efficiency cyclone milling sand flushing in a horizontal well, using the high-efficiency cyclone milling sand flushing device for a horizontal well as claimed in any one of claims 1 to 8 for sand flushing, characterized in that: Specifically, the sand flushing device is assembled, the sand flushing string is connected, the sand flushing string is lowered into the casing, the location of the sand scale in the well is explored, the wellhead oil pipe is connected to the sand flushing pump truck, the pump is turned on to perform the sand flushing and grinding operation, and the sand flushing liquid flows from the oil pipe through the centralizer and the inner cavity of the upper joint of the sand flushing device into the inner cavity of the core tube (17), and then provides three-level positive rotation power for the sand flushing device, and provides the sand flushing device with rotation and grinding power to achieve sand flushing.

10. The horizontal well high-efficiency cyclone milling sand flushing method according to claim 9, characterized in that: Follow the steps below to implement it: Step 1: Assemble the sandblaster and select the nozzle size according to the sandblasting construction displacement. In order to ensure sufficient jet impact effect without damaging the casing, the jet speed is controlled at 60-100m / s; Step 2, connecting the sand flushing pipe column, the structure of the sand flushing pipe column is composed of a sand flushing device (32), a centralizer (31), and an oil pipe (29) from bottom to top, wherein the centralizer (31) is connected to the sand flushing device (32) and the oil pipe (29) by threads through the oil pipe (29); Step 3: insert a sand flushing string into the casing (30), slowly lower the string, and explore the location of the sand scale (33) downhole; Step 4: After sand scale is detected, lift the pipe column by 0.3-0.5 meters, connect the wellhead oil pipe to the sand flushing pump truck, set the sand flushing displacement, and start the pump to perform sand flushing and milling operations; Step 5, the sand flushing liquid flows from the oil pipe through the centralizer (31) and the inner cavity of the upper joint of the sand flushing device (32) into the inner cavity of the core tube (17), and flows out from the square hole (14) provided at the connection end between the core tube (17) and the inner spiral sand flushing device body (8), and impacts the spiral teeth of the inner spiral sand flushing device body (8). The inner spiral sand flushing device body (8) is a right-hand spiral, and the fluid generates a rotational torque on the inner spiral in the positive direction, i.e., the tightening direction of the core shaft thread, thereby providing the first-level rotational power for the sand flushing device; Step 6: After the sand washing liquid comes out from the left side of the inner spiral sand washing device body (8), 1 / 3 enters through the side through hole (26) of the inner spiral sand washing device body (8) and is ejected from the axial nozzle (2) of the outer spiral sand washing device body (7) to impact the sand bridge in front. 2 / 3 of the sand washing liquid enters through the axial hole (4) of the outer spiral sand washing device body (7) and is ejected from the four lateral nozzles (34) of the outer spiral sand washing device body (7), generating both a jet force to the side and front and a circumferential tangential jet force. The reaction of the circumferential tangential jet generates a positive rotation torque on the outer spiral, providing a second-stage rotation power for the sand washing device. Step 7, the fluid ejected from the axial nozzle (2) of the external spiral sand washer body (7) returns from the diverter groove (22), flows through the right-angle guide groove (23), and returns from the spiral guide groove a (24) on the cylindrical surface of the external spiral sand washer body (7) together with the fluid returned from the corresponding lateral nozzle (34), and returns to the ground through the annulus of the oil pipe (29) and the casing (30). The external spiral sand washer body (7) is a left-hand spiral, and the fluid flowing through the spiral guide groove b (27) generates a positive rotation torque on the external spiral sand washer body (7), providing the third-level rotation power of the sand washer; The three-stage positive rotational power provides sufficient rotational milling power for the sand flusher, thereby clearing the stubborn scale and stone on the inner wall of the casing (30), flushing and unblocking the perforation blasthole blockage on the casing (30), breaking the stubborn scale and stone in the milling casing, and realizing sand flushing.

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