Reverse circulation valve that can be opened and closed repeatedly

Abstract

The present invention relates to the technical field of oil well flushing equipment, and is a reverse circulation valve that can be repeatedly opened and closed, which includes an upper joint, a spring seat, a valve body, a piston and a compression spring. The present invention has a reasonable and compact structure and is easy to use. When performing well washing fluid operations, hot well washing fluid is first introduced into the annulus, and the hot well washing fluid is filtered by a filter tube and enters the third straight hole through a liquid inlet, and then the hot well washing fluid can push the sealing ball and the piston to compress the compression spring upward to open the liquid passage groove, and the hot well washing fluid can first enter the valve hole through the liquid passage groove and then enter the oil pipe and finally return to the ground along the oil pipe. After the well washing operation is completed, the sealing ball and the piston can close the fourth straight hole again under the action of their own weight and the restoring force of the compression spring, and then normal production operations can be carried out; therefore, the present reverse circulation valve can realize multiple effective openings and automatic closings, and the action execution speed is fast, and the spherical seal formed by the sealing ball and the conical groove cooperates with the sealing ring for better sealing performance.

Description

Technical Field

[0001] The invention relates to the technical field of oil well flushing equipment, and relates to a reverse circulation valve which can be opened and closed repeatedly. Background Art

[0002] At present, for oil wells with high viscosity of crude oil, in order to reduce the cost of pump inspection and extend the pump inspection cycle, the main production process is to first reduce the viscosity by natural gas throughput, then pump and dilute with machine and add periodic reverse circulation hot washing, that is, hot washing well fluid is introduced from the annulus between the tubing and the casing, and the piston of the reverse circulation valve is pushed by the hot washing well fluid. After the piston moves, the hot washing well fluid enters the tubing from the annulus through the liquid inlet hole on the reverse circulation valve, and finally returns from the tubing to the ground, completing the reverse circulation valve well washing process. Since this process requires periodic reverse circulation hot washing, it has high requirements for the reverse circulation valve in the well, and the reverse circulation valve needs to be able to be effectively opened and closed many times.

[0003] The reverse circulation valves currently in use have the following problems due to their structure and material: First, after opening some reverse circulation valves, a large amount of well washing fluid needs to be injected to form a sufficient throttling pressure difference in order to push the sleeve to move and close. However, when currently used in production tubing, the required injection displacement cannot be reached, making it difficult to close. In addition, the sealing method of the currently widely used reverse circulation valves is to rely on sealing rings, but when they are lowered into the well as completion tools, the time spent in the well is long, and the high temperature in the well causes the sealing ring to age rapidly. In addition, when the switch is active, the sealing ring needs to pass through the outer surface of the third straight hole. Under repeated switching actions, the sealing ring is easily sheared and broken, resulting in failure of the reverse circulation valve seal. Summary of the invention

[0004] The present invention provides a reverse circulation valve that can be repeatedly opened and closed, which overcomes the above-mentioned shortcomings of the prior art and can effectively solve the problem of the difficulty of closing after opening of the prior reverse circulation valve, and further solves the problem of short effective period of the seal.

[0005] The technical solution of the present invention is achieved through the following measures: a reverse circulation valve that can be repeatedly opened and closed, including an upper joint, a spring seat, a valve body, a piston and a compression spring, the upper joint is provided with a connecting hole, a first straight hole and a second straight hole from top to bottom, the spring seat is fixedly installed in the first straight hole, the valve body with the lower end located below the upper joint is fixedly installed in the second straight hole, a valve hole that passes through the upper and lower parts is provided in the middle of the valve body, a through hole that passes through the upper and lower parts is provided on the spring seat corresponding to the position of the valve hole, an upper ring groove with an opening downward is provided at the lower end of the spring seat, and at least one spring hole is evenly distributed along the circumference at the upper end of the spring seat corresponding to the position of the upper ring groove. A load-releasing hole that passes through from top to bottom, a lower ring groove with an opening facing upward is provided on the upper end of the valve body corresponding to the position of the upper ring groove, a compression spring is provided between the upper ring groove and the lower ring groove, at least two groups of third straight holes and fourth straight holes with openings facing upward and inner diameters increasing from bottom to top are evenly distributed along the circumference on the valve body corresponding to the position of the lower ring groove, the lower end of the third straight hole is located below the upper joint, a piston is provided in the fourth straight hole corresponding to the lower side of the compression spring, a liquid-passing groove that connects the valve hole and each fourth straight hole is provided on the valve body corresponding to the upper end of the piston, and a liquid inlet that passes through inside and outside and is inclined downward is provided on the valve body corresponding to the lower end of each third straight hole.

[0006] The following are further optimizations and / or improvements to the above technical solutions:

[0007] The above may also include a spring washer, which is arranged in the lower ring groove corresponding to the position between the lower end of the compression spring and the upper end of the piston.

[0008] The above can also include a filter tube, which is fixedly installed on the outside of the valve body corresponding to the liquid inlet, and a plurality of filter holes that penetrate inside and outside are evenly distributed along the circumference of the filter tube corresponding to the liquid inlet.

[0009] The above can also include a sealing ball. A conical groove with a larger upper part and a smaller lower part is provided on the valve body corresponding to the position between the third straight hole and the fourth straight hole. A sealing ball is provided in the conical groove, and the upper end of the sealing ball abuts against the lower end of the piston.

[0010] The above may also include a locking screw, and the lower end of the upper joint is evenly distributed with at least one threaded hole that passes through the inside and outside. The valve body corresponding to the position of each threaded hole is provided with a fixing hole opening outward, and each fixing hole is provided with a locking screw with the outer end located in the threaded hole.

[0011] The above-mentioned may also include a first sealing ring and a second sealing ring, at least two groups of first sealing rings are arranged at intervals between the outer side of the lower end of the piston and the inner side of the fourth straight hole, the upper end of the fourth straight hole is provided with an inner ring groove with the lower end located below the liquid passing groove, and the outer side of the upper end of the piston is provided with an outer ring platform with the outer end located in the inner ring groove; at least two groups of second sealing rings are arranged at intervals between the inner side of the lower end of the upper joint and the outer side of the upper part of the valve body.

[0012] The invention has a reasonable and compact structure and is easy to use. When performing a well washing fluid operation, hot well washing fluid is first introduced into the annulus, and the hot well washing fluid enters the third straight hole through the liquid inlet after being filtered by the filter tube, and then the hot well washing fluid can push the sealing ball and the piston to compress the compression spring to open the liquid passing groove, and the hot well washing fluid can first enter the valve hole through the liquid passing groove and then enter the oil pipe, and finally return to the ground along the oil pipe. After the well washing operation is completed, the sealing ball and the piston close the fourth straight hole again under the action of their own weight and the restoring force of the compression spring, and then normal production operation can be carried out; therefore, the reverse circulation valve can realize multiple effective openings and automatic closings by controlling the on and off of the hot well washing fluid in the annulus, and the response speed of each opening and closing is fast, and the spherical seal formed by the sealing ball and the tapered groove has better sealing performance after being matched with the sealing ring, and the outer ring platform at the upper end of the piston can ensure that it can reliably move upward along the inner ring groove, and the gap between the lower end of the piston and the inner ring groove can prevent the first sealing ring on the piston from being sheared by the friction of the upper and lower edges of the liquid passing groove, thereby effectively extending the service life of the first sealing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attached Figure 1 It is a schematic diagram of the main half-section structure of the best embodiment of the present invention.

[0014] Attached Figure 2 For attachment Figure 1 Schematic diagram of the main half-section structure of the middle valve body.

[0015] Attached Figure 3 For attachment Figure 2 Schematic diagram of the cross-sectional structure at AA.

[0016] The codes in the accompanying drawings are: 1 is an upper joint, 2 is a spring seat, 3 is a valve body, 4 is a piston, 5 is a compression spring, 6 is a connecting hole, 7 is a valve hole, 8 is an upper ring groove, 9 is a through hole, 10 is a unloading hole, 11 is a lower ring groove, 12 is a third straight hole, 13 is a fourth straight hole, 14 is a liquid groove, 15 is a liquid inlet, 16 is a spring pad, 17 is a filter tube, 18 is a filter hole, 19 is a sealing ball, 20 is a set screw, 21 is a first sealing ring, 22 is a second sealing ring, 23 is an outer ring platform, 24 is a wrench groove, and 25 is a tapered groove. DETAILED DESCRIPTION

[0017] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0018] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The positional relationships such as front, back, top, bottom, left, and right are described according to the layout directions of the drawings in the specification.

[0019] The present invention will be further described below in conjunction with embodiments and drawings:

[0020] As attached Figure 1 , 2 As shown in Figures 3 and 4, the reverse circulation valve that can be repeatedly opened and closed comprises an upper joint 1, a spring seat 2, a valve body 3, a piston 4 and a compression spring 5. The upper joint 1 is provided with a connecting hole 6, a first straight hole and a second straight hole from top to bottom, the spring seat 2 is fixedly installed in the first straight hole, the valve body 3 with the lower end located below the upper joint 1 is fixedly installed in the second straight hole, a valve hole 7 that is connected vertically is provided in the middle of the valve body 3, a through hole 9 that is connected vertically is provided on the spring seat 2 corresponding to the position of the valve hole 7, an upper annular groove 8 with an opening downward is provided at the lower end of the spring seat 2, and at least one unloading hole 10 that is connected vertically is uniformly distributed along the circumference of the upper end of the spring seat 2 corresponding to the position of the upper annular groove 8, and a through hole 9 that is connected vertically is provided on the spring seat 2 corresponding to the position of the upper annular groove 8. A lower annular groove 11 opening upward is provided on the upper end of the valve body 3 at the position, a compression spring 5 is provided between the upper annular groove 8 and the lower annular groove 11, at least two groups of third straight holes 12 and fourth straight holes 13 opening upward and increasing in inner diameter from bottom to top are uniformly distributed along the circumference on the valve body 3 corresponding to the position of the lower annular groove 11, the lower end of the third straight hole 12 is located below the upper joint 1, a piston 4 is provided in the fourth straight hole 13 corresponding to the lower side position of the compression spring 5, a liquid through groove 14 connecting the valve hole 7 and each fourth straight hole 13 is provided on the valve body 3 corresponding to the upper end position of the piston 4, and a liquid inlet 15 penetrating inside and outside and tilted downward is provided on the valve body 3 corresponding to the lower end position of each third straight hole 12. According to the requirements, in order to facilitate the connection with the oil pipe or other tools, the inner side of the upper end of the upper joint 1 and the outer side of the lower end of the valve body 3 can be provided with API standard oil pipe threads; in order to enhance the corrosion resistance of the valve body 3, the surface of the valve body 3 can be coated with anti-corrosion materials such as surface chrome plating; in order to facilitate the disassembly and assembly of the spring seat 2, the spring seat 2 and the first straight hole can be connected by threads, and the lower end of the spring seat 2 can also be provided with a straight or cross wrench groove 24; in order to facilitate the disassembly and assembly of the valve body 3, the outer side of the upper end of the valve body 3 and the second straight hole can be connected by screw threads. Threaded connection; to facilitate the disassembly and assembly of the piston 4, a threaded hole with an opening upward may be provided at the upper end of the piston 4, and a disassembly and assembly wrench matching the threaded hole may be provided; to ensure the normal operation of the compression spring 5, the groove width of the upper ring groove 8 and the lower ring groove 11 should be slightly larger than the outer diameter of the compression spring 5, and the compression spring 5 will be pre-compressed when it is installed to give it a pre-tightening force so that it can reliably support the piston 4; in order to ensure the displacement of the well washing fluid and balance the force of the compression spring 5, four groups of third straight holes 12 and fourth straight holes 13 may be evenly arranged along the circumference of the upper end of the valve body 3.

[0021] By such arrangement, during normal operation, the liquid in the oil pipe can be pumped out of the ground through the valve hole 7, the through hole 9 and the connecting hole 6. At this time, the pressure in the valve is much greater than the pressure in the annulus, and the piston 4 will not be pushed open, so the liquid in the valve will not leak out. When reverse circulation well washing operation is required, the hot well washing fluid is pumped into the annulus and enters the third straight hole 12 through the liquid inlet 15. At this time, the pressure in the annulus is much greater than the pressure in the valve. The hot well washing fluid will push the piston 4 upward to further compress the compression spring 5 and finally open the liquid groove 14, so that the hot well washing fluid enters the valve hole 7 through the liquid groove 14, and finally the hot well washing fluid passes through the through hole 9 and the connecting hole 6. The oil pipe returns to the ground, and the well washing fluid pump is turned off after the well washing is completed to reduce the pressure in the annulus. The piston 4 returns to the initial position under the restoring force of the compression spring 5 and its own weight to block the third straight hole 12; the unloading hole 10 can avoid the pressure in the upper ring groove 8 when the piston 4 presses the compression spring 5, ensuring that the compression spring 5 can be compressed smoothly; in addition, since the piston 4 in the valve is small in size, the displacement of the well washing fluid required to push open each piston 4 is small, and the force required to push each piston 4 back to the initial position is also small. By setting a suitable pre-tightening force of the compression spring 5, the piston 4 can be quickly pushed back to the initial position, which can ensure multiple effective opening and closing.

[0022] The above reverse circulation valve that can be repeatedly opened and closed can be further optimized and / or improved according to actual needs:

[0023] As attached Figure 1 As shown, a spring pad 16 is also included, and a spring pad 16 is arranged in the lower ring groove 11 at a position between the lower end of the compression spring 5 and the upper end of the piston 4. Through such an arrangement, the compression spring 5 can be subjected to a more uniform force when the piston 4 presses the compression spring 5, thereby ensuring the synchronization of the operation of each piston 4, and preventing the individual pistons 4 from compressing the compression spring 5 too fast to open the liquid groove 14 at the corresponding position, so that the well washing fluid flows into the valve hole 7 to reduce the pressure in the annulus, thereby reducing the opening pressure of the remaining pistons 4, making it difficult for the remaining pistons 4 to open.

[0024] As attached Figure 1 , 2 As shown, a filter tube 17 is also included. The filter tube 17 is fixedly installed on the outer side of the valve body 3 corresponding to the liquid inlet 15. The filter tube 17 corresponding to the position of the liquid inlet 15 is evenly distributed along the circumference of the filter tube 17, which is connected inside and outside.

[0025] According to needs, in order to facilitate the disassembly and assembly of the filter tube 17, the inner side of the lower end of the filter tube 17 and the second outer ring groove can be connected by a threaded connection; in order to prevent the filter hole 18 located at the liquid inlet 15 from being blocked and causing the filter tube 17 to fail, a gap should be reserved between the inner side of the upper end of the filter tube 17 and the first outer ring groove; the filter tube 17 is mainly used to filter large particles of impurities in the well washing fluid in the annulus.

[0026] As attached Figure 1 , 2As shown, the valve body 3 further includes a sealing ball 19, and a tapered groove 25 with a larger upper part and a smaller lower part is provided on the valve body 3 corresponding to the position between the third straight hole 12 and the fourth straight hole 13. The sealing ball 19 is provided in the tapered groove 25, and the upper end of the sealing ball 19 abuts against the lower end of the piston 4. Through such a configuration, a one-way valve with a spherical seal can be formed between the sealing ball 19 and the tapered groove 25, that is, the sealing ball 19 can only be pushed away from the lower end of the sealing ball 19, otherwise the sealing ball 19 will be firmly pressed in the tapered groove 25 to form a spherical seal; in addition, in order to prevent the surface of the sealing ball 19 from being corroded and to extend the service life of the sealing ball 19, the sealing ball 19 can use a steel ball with an anti-corrosion treatment (such as chrome plating) on ​​the surface, or can use a material with an anti-corrosion function, such as a chrome ball.

[0027] As attached Figure 1 As shown, it also includes a set screw 20. The lower end of the upper joint 1 is evenly distributed with at least one threaded hole that penetrates inside and outside. The valve body 3 corresponding to each threaded hole position is provided with a fixing hole opening outward, and each fixing hole is provided with a set screw 20 with the outer end located in the threaded hole. By setting in this way, the upper joint 1 and the housing can be prevented from being disengaged.

[0028] As attached Figure 1 As shown, it also includes a first sealing ring 21 and a second sealing ring 22. At least two groups of first sealing rings 21 are arranged between the outer side of the lower end of the piston 4 and the inner side of the fourth straight hole 13 at upper and lower intervals. The upper end of the fourth straight hole 13 is provided with an inner ring groove with the lower end located below the liquid groove 14. The outer side of the upper end of the piston 4 is provided with an outer ring platform 23 with the outer end located in the inner ring groove; at least two groups of second sealing rings 22 are arranged between the inner side of the lower end of the upper joint 1 and the outer side of the upper part of the valve body 3 at upper and lower intervals. Through such an arrangement, the first sealing ring 21 is used to prevent the liquid in the valve from seeping out through the gap between the piston 4 and the liquid groove 14. The outer ring platform 23 at the upper end of the piston 4 enables the piston 4 to be guided when it moves in the inner ring groove, that is, the piston 4 can only move up and down along the inner ring groove without deflecting or tilting. There is a certain gap between the lower end of the piston 4 and the inner ring groove, ensuring that the first sealing ring 21 will not be cut and worn by the upper and lower edges of the liquid groove 14 when the piston 4 moves up and down, so as to extend the service life of the first sealing ring 21; the second sealing ring 22 is mainly used to prevent the liquid in the valve from seeping out from the gap between the upper joint 1 and the valve body 3. In addition, in order to ensure that the surface of the second sealing ring 22 is not scratched by the thread when the second sealing ring 22 is installed, no thread may be provided between the upper joint 1 and the valve body 3 corresponding to the position of the second sealing ring 22.

[0029] The use process of the best embodiment of the present invention (taking the pumping of the production tubing string by a rod pump as an example):

[0030] First connect the lower end of the valve to the packer, then connect the upper end of the valve to the pump seat and ensure that the distance between the valve and the pump seat is not less than ten meters. Then use the oil pipe to lower the pump seat, the valve and the packer to the predetermined position in the pipe column, seal the packer, and then use the sucker rod to lower the rod-type oil pump and seat it in the pump seat.

[0031] During normal mechanical pumping production, the rod-type oil pump is turned on to pump the liquid in the oil pipe to the ground. At this time, the pressure in the valve is greater than the pressure in the annulus, and the piston 4 blocks the fourth straight hole 13 under the preload force of the compression spring 5. The first sealing ring 21 on the outer side of the lower end of the piston 4 forms a first seal with the fourth straight hole 13; the upper end of the sealing ball 19 is compressed by the liquid in the valve and is tightly pressed into the tapered groove 25, and a spherical seal (the second seal) is formed between the sealing ball 19 and the tapered groove 25; the use of double sealing can effectively prevent the liquid in the valve from leaking out.

[0032] During reverse circulation well washing, first lift the rod-type oil pump out of the pump seat, and then use a pump truck to pump hot well washing fluid into the annulus. At this time, the pressure in the annulus is greater than the pressure in the valve. The hot well washing fluid first passes through the filter tube 17 to filter out large particles of impurities, and then enters the third straight hole 12 through the liquid inlet 15. As the discharge volume of the hot well washing fluid in the annulus increases, the hot well washing fluid will push the sealing ball 19 upward, and then push the sealing ball 19 and the piston 4 to move the spring pad 16 upward and compress the compression spring 5 at the same time, until the second ring groove is opened to connect the valve hole 7 and the third straight hole 12, and then the hot well washing fluid enters the valve hole 7 and returns to the ground from the oil pipe through the through hole 9 and the connecting hole 6, completing the reverse circulation well washing.

[0033] After the reverse circulation well washing operation is completed, the well washing fluid pump on the pump truck is turned off, and the hot well washing fluid in the annulus gradually decreases until it stops flowing. At this time, the pressure in the annulus gradually decreases, and the piston 4 and the sealing ball 19 return to the initial position under the action of their own weight and the restoring force of the compression spring 5. The piston 4 blocks the fourth straight hole 13 again, and the sealing ball 19 and the tapered groove 25 form a spherical seal again, and the valve is closed; the rod pump is seated in the pump seat again to continue normal pumping production. When performing periodic reverse circulation well washing, you only need to repeat the above process.

[0034] By using this valve for periodic reverse circulation hot washing operations, it can be ensured that the valve can be effectively opened and closed multiple times, and the opening and closing process is reliable, fast, and easy to operate, and the automated closing process can improve work efficiency; it has a double sealing mechanism (sealing ring and spherical seal), high sealing reliability and long service life, and when one of the seals fails, it will not affect the normal operation of the valve.

[0035] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A reverse circulation valve that can be repeatedly opened and closed, characterized in that The valve body comprises an upper joint, a spring seat, a valve body, a piston and a compression spring. The upper joint is provided with a connecting hole, a first straight hole and a second straight hole from top to bottom, a spring seat is fixedly installed in the first straight hole, a valve body whose lower end is located below the upper joint is fixedly installed in the second straight hole, a valve hole that passes through from top to bottom is provided in the middle of the valve body, a through hole that passes through from top to bottom is provided on the spring seat corresponding to the position of the valve hole, an upper ring groove opening downward is provided at the lower end of the spring seat, at least one unloading hole that passes through from top to bottom is uniformly distributed along the circumference at the upper end of the spring seat corresponding to the position of the upper ring groove, a lower ring groove opening upward is provided at the upper end of the valve body corresponding to the position of the upper ring groove, a compression spring is provided between the upper ring groove and the lower ring groove, four groups of third straight holes and fourth straight holes that open upward and whose inner diameters increase successively from bottom to top are uniformly distributed along the circumference on the valve body corresponding to the position of the lower ring groove, the lower end of the third straight hole is located below the upper joint, and the spring seat corresponding to the position of the upper ring groove is provided with a through hole that passes through from top to bottom. A piston is arranged in the fourth straight hole at the lower side of the compression spring, a liquid-passing groove connecting the valve hole and each fourth straight hole is arranged on the valve body at the corresponding upper end of the piston, and a liquid inlet which is connected inside and outside and inclined downward is arranged on the valve body at the corresponding lower end of each third straight hole; a tapered groove which is larger at the top and smaller at the bottom is arranged on the valve body at the position between the third straight hole and the fourth straight hole, and a sealing ball whose upper end abuts against the lower end of the piston is arranged in the tapered groove; a spring pad is arranged in the lower ring groove at the position between the lower end of the compression spring and the upper end of the piston; at least two groups of first sealing rings are arranged at intervals between the outer side of the lower end of the piston and the inner side of the fourth straight hole, an inner ring groove whose lower end is located below the liquid-passing groove is arranged at the upper end of the fourth straight hole, and an outer ring platform whose outer end is located in the inner ring groove is arranged on the outer side of the upper end of the piston; at least two groups of second sealing rings are arranged at intervals between the inner side of the lower end of the upper joint and the outer side of the upper part of the valve body.

2. The reverse circulation valve that can be repeatedly opened and closed according to claim 1 is characterized in that It also includes a filter tube, which is fixedly installed on the outer side of the valve body corresponding to the liquid inlet, and a plurality of filter holes that penetrate inside and outside are evenly distributed along the circumference of the filter tube corresponding to the liquid inlet.

3. The reverse circulation valve that can be repeatedly opened and closed according to claim 1 or 2, characterized in that It also includes a locking screw. The lower end of the upper joint is evenly distributed on the circumference with at least one threaded hole that passes through the inside and outside. The valve body corresponding to the position of each threaded hole is provided with a fixing hole opening outward, and each fixing hole is provided with a locking screw with the outer end located in the threaded hole.

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