Multi-stage staged fracturing sliding sleeve and fracturing tubular column

Abstract

The invention relates to the technical field of oil field staged fracturing, and discloses a multi-stage staged fracturing sliding sleeve and a fracturing tubular column, the multi-stage staged fracturing sliding sleeve comprises a plurality of outer sleeves, the outer sleeves are sequentially connected, and spraying holes are formed in the outer sides of the outer sleeves at equal intervals in a surrounding mode. When the spraying hole opening device is used, redundant fracturing fluid does not need to be consumed to push the inner sleeve to move to open the spraying hole, on one hand, the fracturing fluid is saved, on the other hand, due to the fact that the spraying hole is opened without consuming the fracturing fluid, the time for consuming the redundant fracturing fluid is saved, and the fracturing work efficiency is improved; the whole circular plate composed of the semicircular plates can block fracturing fluid, the fracturing fluid is prevented from entering the circular hole to make contact with the outer sleeve, therefore, the inner sleeve cannot be blocked by the fracturing fluid in the rotating process, it is guaranteed that the inner sleeve can smoothly rotate till the circular hole is aligned with the spraying hole, the semicircular plates can be automatically separated, the spraying hole can be automatically opened, and the working efficiency is improved. And fracturing operation can be carried out.

Description

Technical Field

[0001] The invention belongs to the technical field of oil field staged fracturing, and in particular relates to a multi-stage staged fracturing sliding sleeve and a fracturing pipe column. Background Art

[0002] Horizontal well multi-stage fracturing production enhancement technology plays an important role in improving the development effect of low permeability and low porosity oil and gas reservoirs, increasing single well production and ultimate recovery rate. It is one of the effective means to increase oil field production and injection. It has the advantages of fewer downhole tools, strong targeted operations, and low construction costs. Various downhole sliding sleeve tools connected to the oil casing are used in the horizontal well staged fracturing process. Its purpose is to use packers and sliding sleeves to isolate the horizontal well section into several sections according to the needs of oil and gas reservoir development. During fracturing construction, the sliding sleeve is opened by throwing a ball to carry out targeted construction.

[0003] The sliding sleeve includes an outer sleeve and an inner sleeve arranged inside the outer sleeve. The outer sleeve and the inner sleeve are provided with holes for spraying fracturing fluid. The holes on the outer sleeve and the inner sleeve are not aligned in the initial state. During actual construction, when the inserted sealing ball collides with the base on the corresponding inner sleeve, the fracturing fluid is continuously injected, and the sealing ball is pushed by the fracturing fluid to push the inner sleeve so that the hole on the inner sleeve is aligned with the hole on the outer sleeve. Subsequently, the fracturing fluid is sprayed out from the hole for fracturing. However, a part of the fracturing fluid needs to be wasted in the whole process to push the sealing ball and the inner sleeve to move, so as to align the holes. This wastes the fracturing fluid and increases the engineering time for fracturing.

[0004] Therefore, it is necessary to invent a multi-stage segmented fracturing sleeve and a fracturing string to solve the above problems. Summary of the invention

[0005] In view of the above problems, the present invention provides a multi-stage fracturing sleeve and a fracturing string to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A multi-stage fracturing sleeve comprises a plurality of outer sleeves, which are connected in sequence, the outer side of the outer sleeve is equidistantly surrounded by spray holes, the inner side of the outer sleeve is provided with an inner sleeve, the inner side of the inner sleeve is provided with a circular hole corresponding to the outer sleeve, one end of the inner sleeve is provided with a base, the inner diameters of the plurality of bases decrease in sequence from left to right, an arc groove is provided on the top wall of the outer sleeve, sliding rods are symmetrically fixedly installed in the arc groove, arc blocks are slidably installed on the outside of two sliding rods, the arc blocks are fixedly connected to the inner sleeve, the outer side of the sliding rod is sleeved with a first spring, and the outer side of the arc block is provided with a positioning component for positioning it.

[0007] Furthermore, the positioning assembly includes a positioning hole opened on the top wall of the arc groove, and a slide corresponding to the positioning hole is opened on the inner sleeve and the arc block, a positioning rod cooperating with the positioning hole is slidably installed in the slide, a cavity is opened on the inner wall of the slide, a piston is slidably arranged in the cavity, the piston is fixedly sleeved outside the positioning rod, and a driving assembly for driving it to descend is provided on the outside of the piston.

[0008] Furthermore, the driving assembly includes an annular groove opened on the top of the piston, sodium bicarbonate is arranged in the annular groove, an airbag is fixedly installed on the inner wall of the inner sleeve, a flow channel is opened on the arc block and the inner sleeve, the two ends of the flow channel are respectively connected with the airbag and the annular groove, a vertical rod is fixedly installed on the inner wall of the flow channel, a closing block for closing the flow channel is sleeved on the outside of the vertical rod, a second spring is sleeved on the outside of the vertical rod, the two ends of the second spring are respectively fixedly connected with the closing block and the inner wall of the flow channel, the airbag is an annular rubber airbag, and acetic acid is arranged inside the airbag.

[0009] Furthermore, a slope is provided on the top of the positioning rod, and the positioning hole matches the positioning rod.

[0010] Furthermore, the elastic forces of the plurality of second springs decrease sequentially from left to right.

[0011] Furthermore, a boss is fixedly installed on the inner wall of the circular hole, a pair of semicircular plates are provided inside the circular hole and between the boss and the outer sleeve, grooves are provided on opposite sides of the two semicircular plates, a third spring is provided between the two opposite grooves, and an accommodating groove for accommodating the semicircular plates is provided on the inner wall of the spray hole.

[0012] Furthermore, an inner wall of the accommodating groove on one side away from the inner sleeve is provided with a curved surface.

[0013] Furthermore, the amount of carbon dioxide generated by the reaction of sodium bicarbonate and acetic acid in the annular groove is sufficient to push the piston to move downward with the positioning rod.

[0014] A fracturing pipe string comprises the multi-stage fracturing sliding sleeve as described above.

[0015] Technical effects and advantages of the present invention: 1. The present invention does not need to consume excess fracturing fluid to push the inner casing to open the spray hole when in use, which saves fracturing fluid. Secondly, since no fracturing fluid needs to be consumed to open the spray hole, the time for consuming excess fracturing fluid is saved, thereby improving the efficiency of the fracturing work. 2. The present invention uses a whole circular plate composed of semicircular plates to block the fracturing fluid, preventing the fracturing fluid from entering the circular hole and contacting the outer casing, so that the inner casing will not be hindered by the fracturing fluid during the rotation of the inner casing, ensuring that the inner casing can be smoothly rotated to align the circular hole with the spray hole, and can automatically separate the semicircular plates to open the spray hole so that fracturing operations can be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram showing the structure of a multi-stage fracturing sliding sleeve according to an embodiment of the present invention is shown; Figure 2 A schematic cross-sectional structure diagram of a multi-stage fracturing sleeve according to an embodiment of the present invention is shown; Figure 3 The embodiment of the present invention is shown Figure 2 The enlarged structural diagram at A in the middle; Figure 4 The embodiment of the present invention is shown Figure 1 AA cross-sectional structure diagram; Figure 5 The embodiment of the present invention is shown Figure 4 The enlarged structural diagram at B in the middle; Figure 6 The embodiment of the present invention is shown Figure 1 Schematic diagram of the cross-sectional structure of the middle BB; Figure 7 The embodiment of the present invention is shown Figure 6 The enlarged structural diagram at C in the middle; Figure 8 A schematic diagram of the combined structure of the inner sleeve and the arc block according to an embodiment of the present invention is shown.

[0017] In the figure: 1, outer sleeve; 2, spray hole; 3, inner sleeve; 4, round hole; 5, base; 6, arc block; 7, positioning hole; 8, positioning rod; 9, piston; 10, ring groove; 11, air bag; 12, flow channel; 13, vertical rod; 14, second spring; 15, closing block; 16, sliding rod; 17, first spring; 18, boss; 19, semicircular plate; 20, third spring; 21, receiving groove; 22, arc surface. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0019] The present invention provides a multi-stage fracturing sliding sleeve, such as Figures 1 to 8As shown, it includes multiple outer sleeves 1, which are connected in sequence. The connection method between the multiple outer sleeves 1 is consistent with the connection method between the staged fracturing sleeves in the prior art. The outer side of the outer sleeve 1 is equidistantly surrounded by spray holes 2, the inner side of the outer sleeve 1 is provided with an inner sleeve 3, the inner side of the inner sleeve 3 is provided with a circular hole 4 corresponding to the outer sleeve 1, and one end of the inner sleeve 3 is provided with a base 5. The inner diameters of the multiple bases 5 decrease from left to right. An arc groove is provided on the top wall of the outer sleeve 1, and sliding rods 16 are symmetrically fixedly installed in the arc groove. An arc block 6 is slidably installed on the outside of the two sliding rods 16. The arc block 6 is fixedly connected to the inner sleeve 3, and a first spring 17 is sleeved on the outside of the sliding rod 16. A positioning component for positioning the arc block 6 is provided on the outside.

[0020] When in use, sealing balls of different sizes are put into the inner sleeve 3 in order from small to large. After the sealing ball passes through multiple bases 5, it stops moving after contacting with the base 5 that matches it. When the sealing ball is about to contact with the base 5, the positioning assembly will be cancelled. At this time, the arc block 6 can move along the arc groove, and the compressed first spring 17 releases the force to rotate the arc block 6 and the inner sleeve 3, so that the circular hole 4 on the inner sleeve 3 is rotated to align with the spray hole 2. Finally, the arc block 6 contacts the inner wall of the arc groove and stops, and the sealing ball contacts the corresponding base 5. The sealing ball and the base 5 are the base and sealing ball in the fracturing sleeve in the prior art. The sealing ball and the corresponding After the base 5 is in conflict with the inner casing 3, the fracturing fluid is injected into the inner casing 3, and the fracturing fluid is finally injected into the soil from the circular hole 4 and the spray hole 2 for fracturing. The remaining sealing balls are in conflict with the corresponding base 5 according to the above principle to inject fracturing fluid, which can realize multi-stage segmented fracturing of the soil. In the whole process, when the sealing ball is in conflict with the base 5, the fracturing fluid can be injected and sprayed, and there is no need to consume excess fracturing fluid to push the inner casing 3 to move and open the spray hole 2. On the one hand, fracturing fluid is saved, and on the other hand, since there is no need to consume fracturing fluid to open the spray hole 2, the time of consuming excess fracturing fluid is saved, which improves the efficiency of the fracturing work.

[0021] like Figures 3 to 5 As shown, the positioning assembly includes a positioning hole 7 opened on the top wall of the arc groove, a slideway corresponding to the positioning hole 7 is opened on the inner sleeve 3 and the arc block 6, a positioning rod 8 cooperating with the positioning hole 7 is slidably installed in the slideway, a cavity is opened on the inner wall of the slideway, a piston 9 is slidably arranged in the cavity, the piston 9 is fixedly sleeved outside the positioning rod 8, and a driving assembly for driving it to descend is provided on the outside of the piston 9.

[0022] When the sealing ball passes through the inner sleeve 3, the trigger driving assembly drives the piston 9 to bring the positioning rod 8 down, so that the positioning rod 8 leaves the positioning hole 7. At this time, the positioning of the arc block 6 is cancelled, and the arc block 6 can move in the arc groove.

[0023] like Figures 4 to 5As shown, the driving assembly includes an annular groove 10 opened on the top of the piston 9, and sodium bicarbonate is arranged in the annular groove 10. An airbag 11 is fixedly installed on the inner wall of the inner sleeve 3. A flow channel 12 is opened on the arc block 6 and the inner sleeve 3. The two ends of the flow channel 12 are respectively connected with the airbag 11 and the annular groove 10. A vertical rod 13 is fixedly installed on the inner wall of the flow channel 12. The outer part of the vertical rod 13 is provided with a closing block 15 for closing the flow channel 12. The outer part of the vertical rod 13 is provided with a second spring 14. The two ends of the second spring 14 are respectively fixedly connected with the closing block 15 and the inner wall of the flow channel 12. The airbag 11 is an annular rubber airbag, and acetic acid is arranged inside the airbag 11.

[0024] The sealing ball squeezes the airbag 11 to squeeze the acetic acid inside it outward, and the acetic acid squeezes the closing block 15 through the flow channel 12, overcomes the elastic force of the second spring 14, and pushes the closing block 15 down, so that the flow channel 12 is opened, and the acetic acid enters the annular groove 10 to react with sodium bicarbonate to generate a large amount of carbon dioxide, which pushes the piston 9 to make it go down, thereby bringing the positioning rod 8 down.

[0025] like Figure 5 As shown, the top of the positioning rod 8 is provided with an inclined surface, and the positioning hole 7 matches the positioning rod 8.

[0026] When the positioning rod 8 is located in the positioning hole 7 , the area other than the inclined surface also contacts the inner wall of the positioning hole 7 . The existence of the inclined surface makes it easier for the positioning rod 8 to escape from the positioning hole 7 when it descends.

[0027] like Figure 5 As shown, the elastic forces of the plurality of second springs 14 decrease sequentially from left to right.

[0028] When the small sealing ball thrown in first passes through the airbag 11 that does not correspond to it, it cannot rely on its own weight to squeeze the airbag 11 to squeeze out the acetic acid and overcome the elastic force of the second spring 14 to bring the closing block 15 down to open the flow channel 12. Only when the sealing ball of corresponding weight squeezes the corresponding airbag 11, it can squeeze out the acetic acid and overcome the elastic force of the second spring 14 to bring the closing block 15 down to open the flow channel 12.

[0029] like Figure 6 to Figure 7 As shown, a boss 18 is fixedly mounted on the inner wall of the circular hole 4, a pair of semicircular plates 19 are provided inside the circular hole 4 and between the boss 18 and the outer sleeve 1, grooves are provided on opposite sides of the two semicircular plates 19, a third spring 20 is provided between the two opposite grooves, and a receiving groove 21 for accommodating the semicircular plates 19 is provided on the inner wall of the spray hole 2.

[0030] The injected fracturing fluid is different according to the actual situation. Since the injected pressure fluid is viscous and has high friction resistance, when a fracturing fluid with high viscosity and high friction resistance is injected, part of the fracturing fluid will enter the circular hole 4 on the remaining non-rotating inner casing 3. When the inner casing 3 rotates, the fracturing fluid contacts the inner wall of the outer casing 1 to hinder the rotation of the inner casing 3. Therefore, the entire circular plate composed of the semicircular plates 19 can block the fracturing fluid to prevent the fracturing fluid from entering the circular hole 4 and contacting the outer casing 1, so that the fracturing fluid will not be hindered during the rotation of the inner casing 3, ensuring that the inner casing 3 can be smoothly rotated to align the circular hole 4 with the spray hole 2. When the circular hole 4 is aligned with the spray hole 2, as the fracturing fluid is continuously injected, it moves outward against the semicircular plate 19. When the semicircular plate 19 moves to the receiving groove 21, the compressed third spring 20 releases the force to separate the pair of semicircular plates 19, so that the semicircular plates 19 enter the receiving groove 21, open the spray hole 2, and discharge the fracturing fluid normally.

[0031] like Figure 6 As shown, a curved surface 22 is provided on the inner wall of the receiving groove 21 away from the inner sleeve 3 .

[0032] After the semicircular plate 19 contacts the arc surface 22 , it can be guided along the arc surface 22 into the receiving groove 21 .

[0033] The amount of carbon dioxide generated by the reaction of sodium bicarbonate and acetic acid in the annular groove 10 is sufficient to push the piston 9 and move it downward with the positioning rod 8.

[0034] The present invention also provides a fracturing pipe string, comprising the multi-stage fracturing sliding sleeve as described above.

[0035] Working principle: When in use, different sizes of sealing balls are put into the inner sleeve 3 in order from small to large. After the sealing ball passes through multiple bases 5, it stops moving after contacting with the base 5 that matches it. When the sealing ball is about to contact with the base 5, the sealing ball passes through the airbag 11 to squeeze the airbag 11 to squeeze the acetic acid inside it outward. The acetic acid passes through the flow channel 12 to squeeze the closing block 15, overcomes the elastic force of the second spring 14, and pushes the closing block 15 down, so that the flow channel 12 is opened. When the small sealing ball that is put in first passes through the airbag 11 that does not correspond to it, there is no The method relies on its own weight to squeeze the airbag 11 to squeeze out the acetic acid, overcome the elastic force of the second spring 14, and bring the closing block 15 down to open the flow channel 12. Only when the sealing ball of the corresponding weight can squeeze the corresponding airbag 11, squeeze out the acetic acid, overcome the elastic force of the second spring 14, and bring the closing block 15 down to open the flow channel 12. The acetic acid enters the annular groove 10 and reacts with the sodium bicarbonate to generate a large amount of carbon dioxide, which pushes the piston 9 to make it descend, thereby bringing the positioning rod 8 down, so that the positioning rod 8 leaves the positioning hole 7. At this time, the piston 9 is pushed down and the positioning rod 8 is moved down. The arc block 6 is positioned, and the arc block 6 can move in the arc groove. The compressed first spring 17 releases the force to rotate the arc block 6 and the inner sleeve 3, so that the circular hole 4 on the inner sleeve 3 is rotated to align with the spray hole 2. Finally, the arc block 6 stops in contact with the inner wall of the arc groove, and the sealing ball is in contact with the corresponding base 5. The sealing ball and the base 5 are the base and sealing ball in the fracturing sleeve in the prior art. After the sealing ball is in contact with the corresponding base 5, the fracturing fluid is injected into the inner sleeve 3 at this time, and the fracturing fluid finally flows out from the circular hole 4 and the spray hole 2. Injected into the soil for fracturing, the remaining sealing balls are in conflict with the corresponding base 5 in the same principle as above, and the fracturing fluid is injected, which can realize multi-stage fracturing of the soil. In the whole process, when the sealing ball conflicts with the base 5, the fracturing fluid can be injected and sprayed, and there is no need to consume excess fracturing fluid to push the inner casing 3 to move and open the spray hole 2. On the one hand, fracturing fluid is saved, and on the other hand, since there is no need to consume fracturing fluid to open the spray hole 2, the time of consuming excess fracturing fluid is saved, which improves the efficiency of the fracturing work;The injected fracturing fluid is different according to the actual situation. Since the injected pressure fluid is viscous and has high friction resistance, when a fracturing fluid with high viscosity and high friction resistance is injected, part of the fracturing fluid will enter the circular hole 4 on the remaining non-rotating inner casing 3. When the inner casing 3 rotates, the fracturing fluid contacts the inner wall of the outer casing 1 to hinder the rotation of the inner casing 3. Therefore, the entire circular plate composed of the semicircular plates 19 can block the fracturing fluid to prevent the fracturing fluid from entering the circular hole 4 and contacting the outer casing 1, so that the fracturing fluid will not be hindered during the rotation of the inner casing 3, ensuring that the inner casing 3 can be smoothly rotated to align the circular hole 4 with the spray hole 2. When the circular hole 4 is aligned with the spray hole 2, as the fracturing fluid is continuously injected, it moves outward against the semicircular plate 19. When the semicircular plate 19 moves to the receiving groove 21, the compressed third spring 20 releases the force to separate the pair of semicircular plates 19, so that the semicircular plates 19 enter the receiving groove 21, open the spray hole 2, and discharge the fracturing fluid normally. ;

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. A multi-stage fracturing sliding sleeve, comprising a plurality of outer casings (1), characterized in that: A plurality of outer sleeves (1) are connected in sequence, and the outer side of the outer sleeve (1) is equidistantly surrounded by spray holes (2). An inner sleeve (3) is provided inside the outer sleeve (1), and a circular hole (4) corresponding to the outer sleeve (1) is provided on the inner side of the inner sleeve (3). A base (5) is provided at one end of the inner sleeve (3), and the inner diameters of the plurality of bases (5) decrease from left to right. An arc groove is provided on the top wall of the outer sleeve (1), and slide bars (16) are symmetrically fixedly installed in the arc groove. An arc block (6) is slidably installed on the outside of two slide bars (16), and the arc block (6) is fixedly connected to the inner sleeve (3). A first spring (17) is sleeved on the outside of the slide bar (16), and a positioning component for positioning the arc block (6) is provided on the outside.

2. The multi-stage fracturing sleeve according to claim 1, characterized in that: The positioning assembly comprises a positioning hole (7) formed on the top wall of the arc-shaped groove, a slideway corresponding to the positioning hole (7) formed on the inner sleeve (3) and the arc-shaped block (6), a positioning rod (8) cooperating with the positioning hole (7) being slidably mounted in the slideway, a cavity being formed on the inner wall of the slideway, a piston (9) being slidably mounted in the cavity, the piston (9) being fixedly sleeved outside the positioning rod (8), and a driving assembly for driving the piston (9) to descend being provided on the outside.

3. The multi-stage fracturing sleeve according to claim 2, characterized in that: The driving assembly comprises an annular groove (10) formed on the top of the piston (9), wherein sodium bicarbonate is arranged in the annular groove (10), an air bag (11) is fixedly mounted on the inner wall of the inner sleeve (3), a flow channel (12) is formed on the arc block (6) and the inner sleeve (3), the two ends of the flow channel (12) are respectively connected to the air bag (11) and the annular groove (10), a vertical rod (13) is fixedly mounted on the inner wall of the flow channel (12), a closing block (15) for closing the flow channel (12) is sleeved on the outside of the vertical rod (13), a second spring (14) is sleeved on the outside of the vertical rod (13), the two ends of the second spring (14) are respectively fixedly connected to the closing block (15) and the inner wall of the flow channel (12), the air bag (11) is an annular rubber air bag, and acetic acid is arranged inside the air bag (11).

4. The multi-stage fracturing sleeve according to claim 3, characterized in that: The top of the positioning rod (8) is provided with an inclined surface, and the positioning hole (7) matches the positioning rod (8).

5. The multi-stage fracturing sleeve according to claim 3, characterized in that: The elastic forces of the plurality of second springs (14) decrease sequentially from left to right.

6. The multi-stage fracturing slide according to claim 1, characterized in that: A boss (18) is fixedly mounted on the inner wall of the circular hole (4); a pair of semicircular plates (19) are provided inside the circular hole (4) and between the boss (18) and the outer sleeve (1); grooves are provided on opposite sides of the two semicircular plates (19); a third spring (20) is provided between the two opposite grooves; and a receiving groove (21) for receiving the semicircular plates (19) is provided on the inner wall of the spray hole (2).

7. The multi-stage fracturing sleeve according to claim 6, characterized in that: An inner wall of the receiving groove (21) at a side away from the inner sleeve (3) is provided with a curved surface (22).

8. The multi-stage fracturing sleeve according to claim 7, characterized in that: The amount of carbon dioxide generated by the reaction of sodium bicarbonate and acetic acid in the annular groove (10) is sufficient to push the piston (9) and move it downward with the positioning rod (8).

9. A fracturing string, characterized in that: It comprises the multi-stage fracturing sliding sleeve as described in any one of claims 1 to 8.

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