A compensator with bidirectional compensation function for deep well

Abstract

The present application relates to the technical field of compensator, especially to a compensator with bidirectional compensation function for deep well, which comprises an outer sleeve, fixed rings symmetrically distributed are installed in the outer sleeve, graphite sealing rings are arranged between the fixed rings symmetrically distributed, an inner sleeve is jointly and slidably connected to the fixed rings symmetrically distributed, the outer sleeve and the inner sleeve are in sealing contact with the graphite sealing rings, the outer sleeve is provided with a sliding cylinder, the inner sleeve is provided with a limiting ring, a barrier cloth is fixedly connected between the sliding cylinder and the limiting ring, and the barrier cloth is used for blocking sand and gravel. The present application forms a physical barrier upstream of the graphite sealing ring in the direction of the sand-containing fluid entering, blocks sand and gravel outside the sealing area, reduces the wear contact of sand and gravel with the graphite sealing ring between the graphite sealing ring and the inner sleeve, and reduces the wear rate of the graphite sealing ring.

Description

Technical Field

[0001] This invention relates to the field of compensator technology, and in particular to a compensator for deep wells with bidirectional compensation function. Background Technology

[0002] In reservoir development, the downhole tubing is subjected to periodic alternation of injection pressure, formation temperature, and produced fluid load, resulting in bidirectional expansion and contraction deformation. If the deformation cannot be absorbed, the tubing will directly apply the force generated by the deformation to the packer, causing the packer to be squeezed. In severe cases, the packer may break, making reservoir production impossible and affecting the production progress. Therefore, it is necessary to install a compensator with bidirectional compensation function between the packer and the tubing. Its main function is to absorb the axial expansion and contraction of the tubing, offset the stress, and protect the integrity of the packer. The compensator consists of an outer sleeve connected to the packer and an inner sleeve connected to the tubing. A deformable sealing cavity is formed between the outer sleeve and the inner sleeve. A sealing ring is installed in the sealing cavity to achieve a sealing state when the two slide relative to each other.

[0003] In the development of loose sandstone oil reservoirs, the produced fluids from the well carry a large amount of sand and gravel. The sand and gravel enter the sealing cavity through the sliding gap between the outer casing and the inner casing. The sand and gravel adhere to the wall of the outer casing. When the outer casing moves due to the alternation of injection and production, the sealing ring will be continuously rubbed by the sand and gravel, which aggravates the wear of the sealing ring. As a result, the sealing life of the sealing ring is shortened due to the wear of the sand and gravel, the maintenance frequency is high, and the extraction operation cost is high. Summary of the Invention

[0004] The purpose of this invention is to provide a compensator with bidirectional compensation function for deep wells, so as to solve the shortcomings mentioned in the background above.

[0005] The technical implementation of the present invention is as follows: A compensator for deep wells with bidirectional compensation function includes an outer tube, a symmetrically distributed fixing ring installed inside the outer tube, a graphite sealing ring disposed between the symmetrically distributed fixing rings, and an inner sleeve slidably connected to the symmetrically distributed fixing rings. Both the outer tube and the inner sleeve are in sealing contact with the graphite sealing ring. The outer tube is provided with a sliding cylinder, and the inner sleeve is provided with a limiting ring. A barrier cloth is fixed between the sliding cylinder and the limiting ring, and the barrier cloth is used to block gravel. A reciprocating drive assembly is provided inside the outer tube, and the reciprocating drive assembly is used to drive the limiting ring to rotate. The reciprocating drive assembly includes a fixing member, which is fixed inside the outer tube and slidably connected to the inner sleeve. The inner sleeve is rotatably connected to the sliding ring, and the sliding ring is fixed to a circumferentially distributed limiting plate. The inner sleeve is slidably connected to all the limiting plates, and the limiting plates are provided with guide grooves. The fixing member slides along the guide grooves of all the limiting plates.

[0006] As an improvement to the above solution, one end of the barrier cloth is fixedly connected to the side of the limiting ring near the graphite sealing ring, and the other end of the barrier cloth is fixedly connected to the side of the sliding cylinder near the graphite sealing ring.

[0007] As an improvement to the above solution, a circumferentially distributed elastic strip is fixed between the sliding cylinder and the limiting ring. The circumferentially distributed elastic strip is fixed to the barrier cloth, and the elastic strip is used to enhance the structural strength of the barrier cloth.

[0008] As an improvement to the above solution, the cross-section of the barrier fabric and the cross-section of all the elastic strips are wavy.

[0009] As an improvement to the above solution, the guide groove on the limiting plate is wavy.

[0010] As an improvement to the above solution, it also includes uniformly distributed guide ring frames, all of which are fixed inside the sliding cylinder. The guide ring frames are used to collect and guide the sand and gravel.

[0011] As an improvement to the above solution, a guide portion is provided on the guide ring frame at a position away from the sliding cylinder, and the inner diameter of the guide portion of the guide ring frame gradually increases from the side closer to the limiting ring to the side farther away from the limiting ring.

[0012] As an improvement to the above solution, the limiting ring is slidably connected to a compression ring, the compression ring is fixedly connected to a circumferentially distributed blocking block, the limiting ring is provided with a circumferentially distributed limiting block, the limiting block and the limiting ring are connected by an elastic sheet, the blocking block and the limiting block correspond one-to-one, and the blocking block is used to limit the corresponding limiting block, and the limiting block is used to limit the sliding ring.

[0013] As an improvement to the above solution, a blocking ring is fixedly connected to the sliding cylinder. The blocking ring is made of composite expansion material and is used to compress the inner sleeve.

[0014] Beneficial effects: This invention forms a physical barrier upstream of the graphite sealing ring in the direction of sand-containing fluid entry by using a barrier cloth, which blocks sand and gravel outside the sealing area, reduces the wear contact between sand and gravel and the graphite sealing ring and the inner sleeve, and reduces the wear rate of the graphite sealing ring.

[0015] By using a wavy design for both the barrier cloth and the circumferentially distributed elastic strips, the effective adhesion area of ​​sand and gravel on the barrier cloth surface is reduced, making it easier for sand and gravel to fall off under the action of gravity or fluid. When the elastic strips deform due to the compression of the tubing, the fixing components limit all the limiting plates, causing all the limiting plates to drive the barrier cloth and all the elastic strips to rotate through the sliding ring. This gives the barrier cloth a self-cleaning function, allowing it to be cleaned without additional power.

[0016] By setting circumferentially distributed guide rings on the sliding cylinder, the gravel is guided to an area away from the graphite sealing ring, reducing the adhesion of the gravel to the barrier cloth.

[0017] By pressing the corresponding limit block with the blocking block, the sliding cylinder and the limit ring can be detachably installed and removed from the limit plate through the limit block, which simplifies the maintenance process and reduces maintenance time and operating costs. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a three-dimensional structural diagram of the graphite sealing ring and fixing ring of the present invention; Figure 3 This is a three-dimensional structural diagram of the limiting ring and the barrier cloth of the present invention; Figure 4 This is a three-dimensional structural diagram of the fixing component, sliding ring, and limiting plate of the present invention; Figure 5 This is a three-dimensional structural diagram of the barrier fabric and elastic strip of the present invention; Figure 6 This is a three-dimensional cross-sectional view of the limiting plate and the extrusion ring of the present invention; Figure 7 For the present invention Figure 6 Enlarged 3D structural diagram at point A.

[0019] The components in the attached diagram are labeled as follows: 1-outer sleeve, 2-graphite sealing ring, 3-fixing ring, 4-inner sleeve, 5-sliding cylinder, 6-limiting ring, 7-barrier cloth, 201-elastic strip, 301-fixing component, 302-sliding ring, 303-limiting plate, 401-guide ring frame, 501-compression ring, 502-blocking block, 503-limiting block, 601-blocking ring. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0021] Example 1 During reservoir development, gravel can infiltrate between the outer and inner casings, causing the sealing rings to be continuously rubbed by the gravel as the outer casing moves, thus affecting the sealing life of the sealing rings.

[0022] A compensator with bidirectional compensation function for deep wells, such as Figures 1-3 and Figures 5-7 As shown, it includes an outer tube 1, inside which are symmetrically distributed fixing rings 3, and graphite sealing rings 2 are arranged between the symmetrically distributed fixing rings 3. The symmetrically distributed fixing rings 3 are slidably connected to an inner sleeve 4. Both the outer tube 1 and the inner sleeve 4 are in sealing contact with the graphite sealing rings 2. The outer tube 1 is provided with a sliding cylinder 5, and the inner sleeve 4 is provided with a limit ring 6. A barrier cloth 7 is fixed between the sliding cylinder 5 and the limit ring 6. The barrier cloth 7 is used to block sand and gravel. The outer tube 1 is provided with a reciprocating drive assembly, which is used to drive the limit ring 6 to rotate. One end of the barrier cloth 7 is fixedly connected to the side of the limit ring 6 near the graphite sealing ring 2, and the other end of the barrier cloth 7 is fixedly connected to the side of the sliding cylinder 5 near the graphite sealing ring 2.

[0023] In the above scheme, the outer sleeve 1 has an upper flange, which is bolted to the packer. The inner sleeve 4 has a lower flange and four vertical grooves, which are bolted to the pipe column. In this embodiment, the outer sleeve 1 and the sliding cylinder 5 are considered to be fixedly connected, and the inner sleeve 4 and the limiting ring 6 are considered to be rotatably connected. The limiting ring 6 is used to drive the barrier cloth 7 to move. The barrier cloth 7 forms a physical barrier upstream of the graphite sealing ring in the direction of sand-containing fluid entry, blocking the sand and gravel outside the sealing area, reducing the wear contact between the sand and gravel entering the graphite sealing ring 2 and the inner sleeve 4 and the graphite sealing ring 2, and reducing the wear rate of the graphite sealing ring 2.

[0024] like Figures 5-7 As shown, a circularly distributed elastic strip 201 is fixed between the sliding cylinder 5 and the limiting ring 6. All the circularly distributed elastic strips 201 are fixed to the barrier cloth 7. The elastic strips 201 are used to enhance the structural strength of the barrier cloth 7. The cross section of the barrier cloth 7 and the cross section of all the elastic strips 201 are wavy.

[0025] In the above scheme, four elastic strips 201 are shown. The number of elastic strips 201 can be set according to specific circumstances. The elastic strips 201 are located inside the barrier cloth 7. Initially, the barrier cloth 7 is wavy under the action of the four elastic strips 201, so that when the barrier cloth 7 moves, it can push the sand and gravel on the barrier cloth 7, making it easier for the sand and gravel to fall off under the action of gravity or fluid. When the elastic strips 201 deform due to the extrusion of the tube column, they drive the barrier cloth 7, so that the barrier cloth 7 can clean itself without additional power, which is highly reliable.

[0026] like Figures 2-7 As shown, the reciprocating drive assembly includes a fixing member 301, which is fixedly connected to the outer sleeve 1. The fixing member 301 is slidably connected to the inner sleeve 4. The inner sleeve 4 is rotatably connected to a sliding ring 302. The sliding ring 302 is fixedly connected to circumferentially distributed limiting plates 303. The inner sleeve 4 is slidably connected to all the limiting plates 303. The limiting plates 303 are provided with guide grooves. The fixing member 301 slides along the guide grooves of all the limiting plates 303. The guide grooves on the limiting plates 303 are wavy.

[0027] In the above scheme, the fixing member 301 has a ring and four protruding rods. The protruding rods of the fixing member 301 correspond one-to-one with the vertical grooves of the inner sleeve 4. The sliding ring 302 is located at the upper part of the inner sleeve 4. There are four limiting plates 303, each with a guide groove. The limiting plates 303 correspond one-to-one with the protruding rods of the fixing member 301. The protruding rods of the fixing member 301 slide in the guide grooves of the corresponding limiting plates 303. When the inner sleeve 4 moves up and down, all the limiting plates 303 drive the barrier cloth 7 and all the elastic strips 201 to swing through the sliding rings 302, thereby improving the cleaning effect of the barrier cloth 7 itself.

[0028] Working principle: When the tubing is lowered into the well, the operator connects the lower flange of the inner sleeve 4 to the tubing with bolts, and the upper flange of the outer sleeve 1 to the packer with bolts, thus completing the installation of the downhole compensator. After drilling begins, the downhole produced fluid is transported to the surface through the tubing, downhole compensator, and packer. When the downhole produced fluid reaches the downhole compensator, it first contacts the inner sleeve 4, and then is discharged through the inner wall of the sliding cylinder 5. When the downhole produced fluid passes the upper end of the inner sleeve 4, some of the sand and gravel in the downhole produced fluid will enter between the inner sleeve 4 and the sliding cylinder 5. At this time, the barrier cloth 7 blocks the sand and gravel that have entered between the inner sleeve 4 and the sliding cylinder 5, keeping the sand and gravel outside the sealing area between the inner sleeve 4 and the graphite sealing ring 2, reducing the wear contact between the graphite sealing ring 2 and the sand and gravel, and reducing the wear rate of the graphite sealing ring 2.

[0029] During drilling and pumping operations, when the downhole tubing is affected by factors such as injection pressure and formation temperature, it experiences bidirectional expansion and contraction (taking upward expansion and contraction due to heat as an example). The tubing compresses the inner sleeve 4, causing it to move upward. The inner sleeve 4 then moves the limiting ring 6, sliding ring 302, and all the limiting plates 303 upward together. During this process, the limiting ring 6 moves the upper ends of the barrier cloth 7 and all the elastic strips 201 upward, stretching the barrier cloth 7 and all the elastic strips 201. The graphite sealing ring 2 and the fixing element 301 slide relative to the inner sleeve 4. The sliding ring 302 reciprocates under the interaction of the guide groove of the limiting plate 303 and the protrusion of the corresponding fixing member 301. The sliding ring 302 drives the limiting ring 6 to reciprocate as well. All the limiting plates 303 and the inner sleeve 4 rotate relative to each other. At this time, the barrier cloth 7 and all the elastic strips 201 are stretched and reciprocate, so that the sand and gravel adhering to the surface of the barrier cloth 7 are removed under the action of the swing and the fluid. At the same time, the reciprocating rotation and stretching of the barrier cloth 7 gives the barrier cloth 7 a self-cleaning function, and the barrier cloth 7 can be cleaned without additional power.

[0030] Example 2 Based on Example 1, such as Figure 2 , Figure 3 and Figure 5 As shown, it also includes uniformly distributed guide ring frames 401, which are all fixed inside the sliding cylinder 5. The guide ring frames 401 are used to collect and guide the gravel. A guide part is provided on the guide ring frame 401 away from the sliding cylinder 5. The inner diameter of the guide part of the guide ring frame 401 gradually increases from the side closer to the limiting ring 6 to the side away from the limiting ring 6.

[0031] In the above scheme, six guide ring frames 401 are shown. The number of guide ring frames can be set according to specific circumstances. The guide ring frames 401 are located on the outside of the barrier cloth 7. When the barrier cloth 7 is moved up and down by the inner sleeve 4, the guide ring frames 401 guide the sand and gravel that fall off the barrier cloth 7 to an area away from the graphite sealing ring 2, so as to facilitate the collection of sand and gravel.

[0032] like Figure 1 and Figures 5-7 As shown, the limiting ring 6 is slidably connected to the compression ring 501, and the compression ring 501 is fixedly connected to the circumferentially distributed blocking blocks 502. The limiting ring 6 is provided with circumferentially distributed limiting blocks 503. The limiting blocks 503 and the limiting ring 6 are connected by elastic sheets. The blocking blocks 502 and the limiting blocks 503 correspond one-to-one, and the blocking blocks 502 are used to limit the corresponding limiting blocks 503. The limiting blocks 503 are used to limit the sliding ring 302. The sliding cylinder 5 is fixedly connected to the blocking ring 601, which is made of composite expansion material and is used to compress the inner sleeve 4.

[0033] In the above scheme, there is friction between the limiting ring 6 and the compression ring 501. When the limiting ring 6 is in normal working condition, the limiting ring 6 and the compression ring 501 are relatively stationary. There are four blocking blocks 502 and four limiting blocks 503. The upper side of the limiting block 503 is provided with an inclined surface. The blocking block 502 is used to compress the inclined surface of the corresponding limiting block 503. At this time, the spring plate is in a charged state. The sliding ring 302 has four grooves. In this embodiment, the limiting block 503 is inserted into the groove of the sliding ring 302 for limiting. The sliding cylinder 5 is bolted to the outer sleeve 1 (not shown in the figure). After the sliding cylinder 5 is installed, the upper side of the upper fixing ring 3 is connected to the outer sleeve 1. Contact improves the stability of the sliding cylinder 5. The inner sleeve 4 and the limiting ring 6 are detachably connected, and the limiting ring 6 can rotate along the inner sleeve 4. During maintenance, the blocking block 502 can be removed from the limiting block 503 by moving the squeezing ring 501 upward, thereby making the limiting ring 6 and the limiting plate 303 unfixed. The detachable installation of the sliding cylinder 5 and its parts simplifies the maintenance process and greatly reduces maintenance time and operating costs. The blocking ring 601 expands after contacting liquid and contacts the inner sleeve 4. The contact position between the graphite sealing ring 2 and the inner sleeve 4 is pre-cleaned to reduce the wear of the graphite sealing ring 2.

[0034] Working principle: When the inner sleeve 4 moves the upper ends of the barrier cloth 7 and all the elastic strips 201 upward, the barrier cloth 7 deforms, causing the sand and gravel on the barrier cloth 7 to fall off. The fallen sand and gravel are guided outward through the guide ring frame 401 and guided to the area away from the graphite sealing ring.

[0035] After the produced fluid in the well comes into contact with the blocking ring 601, the blocking ring 601 expands and comes into contact with the inner sleeve 4. When the inner sleeve 4 moves up and down, the blocking ring 601 cleans the contact position of the inner sleeve 4 in advance, reducing the friction between the graphite sealing ring 2 and the inner sleeve 4.

[0036] When this device requires maintenance, the operator pulls the compression ring 501 upwards. The compression ring 501 moves all the blocking blocks 502 upwards together, and the blocking blocks 502 lose contact with the corresponding limiting blocks 503. All the elastic sheets release their elasticity, and all the limiting blocks 503 lose their limiting position with the sliding ring 302. As the compression ring 501 continues to be pulled upwards, it moves the limiting ring 6 upwards. The limiting ring 6 moves the corresponding limiting blocks 503 together through all the elastic sheets. The limiting ring 6 moves the barrier cloth 7 and all the elastic strips 201 upwards together. The barrier cloth 7 and all the elastic strips 201 together move the sliding cylinder 5 upwards together. The sliding cylinder 5 loses contact with the upper fixing ring 3. The sliding cylinder 5 moves the blocking ring 601 and all the guide ring frames 401 together. During this process, the sliding cylinder 5 slides relative to the outer tube 1. Then, the sliding cylinder 5 loses contact with the outer tube 1, completing the removal of the compression ring 501 and its parts.

[0037] After removing the parts from the compression ring 501, the worker installs the unused compression ring 501 and its parts. The worker moves the unused compression ring 501 and its parts downwards, and the sliding cylinder 5 contacts the outer sleeve 1 until the sliding cylinder 5 contacts the upper side of the upper fixing ring 3. At this time, the limiting block 503 contacts the sliding ring 302. Then the worker continues to lower the compression ring 501, so that the blocking block 502 squeezes the inclined surface of the corresponding limiting block 503. The limiting block 503 enters the groove of the sliding ring 302 for limiting, so that the sliding cylinder 5 and the limiting ring 6 and its parts can be detachably installed and removed from the limiting plate 303 through the limiting block 503, simplifying the maintenance process and reducing maintenance time and operating costs.

[0038] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A compensator for deep wells with bidirectional compensation function, comprising an outer sleeve (1), wherein symmetrically distributed fixing rings (3) are installed inside the outer sleeve (1), and graphite sealing rings (2) are disposed between the symmetrically distributed fixing rings (3), and the symmetrically distributed fixing rings (3) are slidably connected to an inner sleeve (4), wherein both the outer sleeve (1) and the inner sleeve (4) are in sealing contact with the graphite sealing rings (2), characterized in that: The outer sleeve (1) is provided with a sliding cylinder (5), the inner sleeve (4) is provided with a limiting ring (6), and a barrier cloth (7) is fixed between the sliding cylinder (5) and the limiting ring (6). The barrier cloth (7) is used to block sand and gravel. A reciprocating drive assembly is provided inside the outer sleeve (1). The reciprocating drive assembly is used to drive the limiting ring (6) to rotate. The reciprocating drive assembly includes a fixing member (301), which is fixedly connected to the outer sleeve (1). The fixing member (301) is slidably connected to the inner sleeve (4). The inner sleeve (4) is rotatably connected to a sliding ring (302). The sliding ring (302) is fixedly connected to circumferentially distributed limiting plates (303). The inner sleeve (4) is slidably connected to all the limiting plates (303). The limiting plates (303) are provided with guide grooves. The fixing member (301) slides along the guide grooves of all the limiting plates (303).

2. The compensator with bidirectional compensation function for deep wells according to claim 1, characterized in that: One end of the barrier cloth (7) is fixedly connected to the side of the limiting ring (6) near the graphite sealing ring (2), and the other end of the barrier cloth (7) is fixedly connected to the side of the sliding cylinder (5) near the graphite sealing ring (2).

3. A compensator with bidirectional compensation function for deep wells according to claim 2, characterized in that: A circularly distributed elastic strip (201) is fixed between the sliding cylinder (5) and the limiting ring (6). The circularly distributed elastic strip (201) is fixed to the barrier cloth (7). The elastic strip (201) is used to enhance the structural strength of the barrier cloth (7).

4. A compensator with bidirectional compensation function for deep wells according to claim 3, characterized in that: The cross-section of the barrier fabric (7) and all the cross-sections of the elastic strips (201) are wavy.

5. A compensator with bidirectional compensation function for deep wells according to claim 1, characterized in that: The guide groove on the limiting plate (303) is wavy.

6. A compensator with bidirectional compensation function for deep wells according to claim 1, characterized in that: It also includes uniformly distributed guide ring frames (401), which are all fixed inside the sliding cylinder (5). The guide ring frames (401) are used to collect and guide the gravel.

7. A compensator with bidirectional compensation function for deep wells according to claim 6, characterized in that: The guide ring frame (401) is provided with a guide part at a position away from the sliding cylinder (5), and the inner diameter of the guide part of the guide ring frame (401) gradually increases from the side close to the limiting ring (6) to the side away from the limiting ring (6).

8. A compensator with bidirectional compensation function for deep wells according to claim 3, characterized in that: The limiting ring (6) is slidably connected to a compression ring (501), and the compression ring (501) is fixedly connected to a circumferentially distributed blocking block (502). The limiting ring (6) is provided with a circumferentially distributed limiting block (503). The limiting block (503) and the limiting ring (6) are connected by an elastic sheet. The blocking block (502) and the limiting block (503) correspond one-to-one. The blocking block (502) is used to limit the corresponding limiting block (503), and the limiting block (503) is used to limit the sliding ring (302).

9. A compensator with bidirectional compensation function for deep wells according to claim 6, characterized in that: A blocking ring (601) is fixedly connected to the sliding cylinder (5). The blocking ring (601) is made of composite expansion material and is used to compress the inner sleeve (4).

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