Large diameter closable staged fracturing sliding sleeve

Abstract

The invention relates to the technical field of fracturing construction, specifically a large-diameter closable segmented fracturing sliding sleeve, comprising a shell and a closable sliding sleeve arranged in the shell, the end front of the connecting section is provided with a back-stop lock ring with an outer diameter larger than the inner diameter of the connecting section, the inner wall of the back-stop lock ring is provided with an internal thread, and the closable sliding sleeve is provided with an outer sleeve, an inner sleeve and a soluble valve core in sequence from the outside to the inside, the lower part of the outer sleeve is provided with an outer thread matching the internal thread, the middle part of the inner wall is provided with a key groove circumferentially, one end of the inner sleeve is provided with a plurality of evenly distributed U-shaped gaps circumferentially, and the outer wall is provided with a key block matching the key groove, the soluble valve core comprises a push rod, both ends of the push rod are provided with a top block and a slider respectively, the end of the push rod close to the slider is provided with a locking ring, a shear pin is provided between the lock ring and the push rod, and the inner wall of the end of the inner sleeve with the U-shaped gap is provided with a clamping groove for clamping the locking ring.

Description

Technical Field

[0001] The invention relates to the technical field of fracturing construction, in particular to a large-diameter closable segmented fracturing sliding sleeve. Background Art

[0002] At present, oil resources are becoming increasingly scarce, and improving the "cost-effectiveness" of a well has gradually become the direction of oil production. Therefore, fracturing construction is needed to achieve the oil output of a single well. As drilling continues to go deeper, the formation structure becomes more and more complex, which can easily cause downhole accidents. This puts forward new requirements for construction technology and downhole tools.

[0003] Currently, most of the existing integrated completion and fracturing construction methods use layered and casing-in-bridge plugging technology.

[0004] Existing layered construction methods employ intermittent, segmented construction, resulting in long construction cycles for individual layers. After completion, the ground capacity is significantly lost, preventing the desired design targets from being achieved. Bridge plug construction requires independent surface delivery, increasing the investment in surface equipment and requiring separate handling for subsequent well retention tools. Summary of the Invention

[0005] In response to the above problems, the present invention provides a large-diameter closable staged fracturing sliding sleeve, which solves the problems existing in the construction process and downhole tools in the background technology.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a large-diameter closable segmented fracturing sleeve, comprising a shell and a closable sleeve arranged in the shell, wherein the two ends of the shell are respectively provided with a detachable upper connector and a lower connector, and the end of the shell close to the upper connector is circumferentially provided with a plurality of evenly distributed fracturing sand interception holes, and the lower connector comprises a cut-off section and a connecting section connected to the shell, wherein the inner diameter of the cut-off section is smaller than the inner diameter of the connecting section, and a back-stop lock ring with an outer diameter larger than the inner diameter of the connecting section is provided at the front end of the connecting section, and the inner wall of the back-stop lock ring is provided with an internal thread, The closable sleeve is provided with an outer sleeve, an inner sleeve and a soluble valve core in sequence from the outside to the inside. The lower part of the outer sleeve is provided with an outer thread matching the inner thread, and a key groove is circumferentially provided in the middle part of the inner wall. One end of the inner sleeve is circumferentially provided with a plurality of evenly distributed U-shaped gaps, and the outer wall is provided with a key block matching the key groove. The soluble valve core includes a push rod, and the two ends of the push rod are respectively provided with a top block and a slider. A locking ring is provided at one end of the push rod close to the slider, and a shear pin is provided between the lock ring and the push rod. The inner wall of the end of the inner sleeve with the U-shaped gap is provided with a groove for clamping the lock ring.

[0007] As an optimization, the outer sleeve and the inner sleeve are both provided with a plurality of straight grooves evenly distributed in the circumferential direction, and the straight grooves on the inner sleeve are in the shape of through holes running through the inside and outside.

[0008] As an optimization, a slope angle is provided inside the end of the outer sleeve with the straight groove.

[0009] As an optimization, the outer wall of the inner sleeve is provided with a spiral groove.

[0010] As an optimization, sealing grooves are provided on the outer sliding sleeve and the inner sliding sleeve, and sealing rings are provided in the sealing grooves.

[0011] As an optimization, a wear-resistant layer is provided at the fracturing sand interception hole.

[0012] As an optimization, the outer sliding sleeve and the inner sliding sleeve are both made of highly elastic materials.

[0013] As an optimization, the locking ring is C-shaped.

[0014] As an optimization, the upper connector and the lower connector are both threadedly connected to the shell.

[0015] The beneficial effects of the present invention are as follows: the large-diameter closable segmented fracturing sleeve provided by the present invention has an outer wall of a fracturing sand intercepting hole provided with a wear-resistant layer to prevent high-speed fluid from eroding the intercepting hole of the tool; the C-type stop lock ring can realize the downward step locking of the closable sleeve, and the closable sleeve can be rotated to realize the closure of the intercepting hole; the straight grooves on the outer sleeve and the inner sleeve can prevent sand blockage, and the slope angle setting at the end of the outer sleeve is intended to flush out the solid matter retained in the straight groove by displacing liquid to prevent the straight groove from failing; the U-shaped gap of the inner sleeve is intended to increase elasticity and facilitate the squeezing of the lock ring, and the outer wall has a spiral groove to carry away mud and sand during the lowering process, reduce the amount of mud and sand deposition, and at the same time increase elasticity and can shrink in diameter after being subjected to downward pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 It is a schematic diagram of the cross-sectional structure of the present invention;

[0018] Figure 3 This is a schematic diagram of the inner sleeve structure of the present invention;

[0019] Figure 4 This is a schematic diagram of the outer sleeve structure of the present invention;

[0020] Figure 5 This is a schematic diagram of the soluble valve core structure of the present invention;

[0021] Figure 6 This is a schematic diagram of the connection method and the lowering sequence structure of the present invention;

[0022] Figure 7 This is a schematic diagram of the upper limit position structure of the present invention;

[0023] Figure 8 This is a schematic diagram of the lower limit position structure of the present invention;

[0024] Figure 9 This is a schematic diagram of the inner sleeve sand flushing design structure of the present invention;

[0025] Figure 10 This is a schematic diagram of the outer sleeve sand flushing design structure of the present invention.

[0026] Wherein: 1. Shell, 2. Upper connector, 3. Lower connector, 4. Fracturing sand cutoff hole, 5. Cut-off section, 6. Connecting section, 7. Outer sleeve, 8. Inner sleeve, 9. Soluble valve core, 10. Keyway, 11. U-shaped gap, 12. Key block, 13. Push rod, 14. Top block, 15. Slider, 16. Locking ring, 17. Shear pin, 18. Slot, 19. Straight groove, 20. Slope angle, 21. Spiral groove, 22. Sealing groove. DETAILED DESCRIPTION

[0027] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0030] like Figure 1-5As shown, a large-diameter closable segmented fracturing sleeve comprises a shell 1 and a closable sleeve arranged in the shell 1. The two ends of the shell 1 are respectively provided with a detachable upper connector 2 and a lower connector 3. The upper connector 2 and the lower connector 3 are both threadedly connected to the shell 1. A plurality of evenly distributed fracturing sand intercepting holes 4 are circumferentially provided at one end of the shell 1 close to the upper connector 2. The fracturing sand intercepting holes 4 are provided with a wear-resistant layer to prevent high-speed fluid from eroding the fracturing sand intercepting holes 4. The lower connector 3 comprises a cut-off section 5 and a connecting section 6 connected to the shell 1. The cut-off section 5 and the connecting section 6 are connected in one piece. The inner diameter of the cut-off section 5 is smaller than the inner diameter of the connecting section 6, and a back-stop lock ring 16 with an outer diameter larger than the inner diameter of the connecting section 6 is provided at the front end of the connecting section 6. The back-stop lock ring 16 is C-shaped, which can realize the downward step locking of the closable sleeve, and the closable sleeve is rotated to realize the closure of the intercepting hole; the inner wall of the back-stop lock ring 16 is provided with an internal thread; the closable sleeve is provided with an outer sleeve 7, an inner sleeve 8 and a soluble valve core 9 in sequence from the outside to the inside, and the axial lengths of the outer sleeve 7 and the inner sleeve 8 are the same; the lower part of the outer sleeve 7 is provided with an external thread matching the internal thread, and the thread form is a non-reversible type to prevent it from going down to the bottom In order to prevent the outer sleeve 7 from slipping out after being in position or slipping in before starting to work, the outer sleeve 7 can be pressed down to expand the C-type anti-retraction lock ring 16, thereby inserting the outer sleeve 7, or the outer sleeve 7 can be rotated to insert the outer sleeve 7 along the thread. Due to the non-reversible thread form, it cannot be retreated after being in position; a key groove 10 is circumferentially provided on the middle part of the inner wall of the outer sleeve 7, and a plurality of evenly distributed U-shaped gaps 11 are circumferentially provided on one end of the inner sleeve 8, the purpose is to increase the elasticity and facilitate the squeezing of the lock ring 16, and a key block 12 matching the key groove 10 is provided on the outer wall to clamp the inner sleeve 8, and a spiral groove 21 is provided on the outer wall of the inner sleeve 8. During the lowering process, the silt is removed, reducing the amount of silt deposited. It also increases elasticity and can shrink in diameter when subjected to downward pressure. The soluble valve core 9 includes a push rod 13, with a top block 14 and a slider 15 at each end. A lock ring 16 is sleeved on the end of the push rod 13 near the slider 15. A shear pin 17 is provided between the lock ring 16 and the push rod 13. When the hydraulic end applies pressure, the soluble valve core 9 descends, driving the inner sleeve 8 into the outer sleeve 7, pushing the outer sleeve 7 downward to open the fracturing sand intercepting hole 4. Continued pressure causes the push rod 13 to shear the shear pin, separating the push rod 13 from the lock ring 16. A slot 18 for retaining the lock ring 16 is provided on the inner wall of the end of the inner sleeve 8 with the U-shaped gap 11. During use, the inner sleeve 8 is dropped from the wellhead and pushed into the inner cavity of the preset outer sleeve 7 by high-pressure pumping on the ground. The maximum outer diameter axial length of the inner sleeve 8 is consistent with the axial length of the inner cavity of the outer sleeve 7, and it can pass through the casing without obstacles.

[0031] Both the outer sleeve 7 and the inner sleeve 8 are equipped with a number of straight grooves 19 evenly distributed around the circumference. The straight grooves 19 on the inner sleeve 8 are through-holes extending from the inside to the outside. The end of the outer sleeve 7 with the straight grooves 19 is internally provided with a slope angle 20 to flush out solid matter trapped within the straight grooves 19 with displacement fluid, thus preventing the straight grooves 19 from failing. Both the outer sleeve 7 and the inner sleeve 8 are provided with sealing grooves 22, each containing a sealing ring. Both the outer sleeve 7 and the inner sleeve 8 are made of highly elastic material, allowing them to shrink and expand in response to external forces, and quickly return to their original state upon release. When the maximum diameter of the staged fracturing sleeve is reached, hydraulic thrust enters the inner cavity, compressing the outer diameter and then continuing downward until release.

[0032] Working principle: The large diameter closable segmented fracturing sleeve provided by the present invention can be used. Figure 6 As shown, the outer sleeve 7 is placed in a suitable position inside the housing, the soluble valve core 9 is inserted into the groove 18 end of the inner sleeve 8, and the soluble valve core 9 and the inner sleeve 8 are lowered into the inner cavity of the outer sleeve 7; after being lowered, as shown in FIG. Figure 7 As shown, at this time, the key block 12 of the inner sleeve 8 is just stuck in the key groove 10 of the outer sleeve 7, achieving self-locking. Continue to pressurize the push rod 13 on the soluble valve core 9, and the shear pin 17 is sheared off due to the resistance of the lock ring 16 in the groove 18. The push rod 13 is separated from the lock ring 16 and moves downward until it reaches the position shown in FIG. Figure 8 At the position shown, push rod 13 continues downward, driving outer sleeve 7 downward until it strikes cutoff section 5 on lower connector 3. The shutoff orifice opens, and the system enters operation. The inner sleeve 8 and outer sleeve 7 remain fixed together. The above illustrates the workflow for a single, large-diameter, closable, staged fracturing sleeve, one for each layer.

[0033] In addition, if the fracturing sleeve channel of a fracturing layer section needs to be fully opened during fracturing construction, it is only necessary to lower a soluble valve core 9 and an inner sleeve 8. After lowering the soluble valve core 9 and the inner sleeve 8, the outer sleeve 7 is pushed in to open the intercepting hole. The hydraulic end continues to apply pressure, the inner sleeve 8 shrinks in diameter, slides out of the key groove 10 of the outer sleeve 7, rushes out of the shell, and goes to the next level. In this way, after all the intercepting holes are opened one after another, it falls on the last level, realizing a multi-cluster in one section.

[0034] like Figure 9-10The sand cleaning design shown is as follows: during the lowering of the large-diameter closable staged fracturing sleeve, a large amount of mud and sand will accumulate on the pipe wall. In order to allow the mud and sand to flow out smoothly, a spiral groove 21 is designed on the outer wall of the inner sleeve 8. The mud and sand will be discharged smoothly along the spiral groove 21, which will greatly reduce the mud and sand remaining inside the sleeve after it is in place. After it is in place, some of the mud and sand will be deposited in the key groove 10. In order to discharge the deposited mud and sand, a straight groove 19 is designed on the inner wall of the outer sleeve 7. The hydraulic end cooperates with the straight groove 19 to take the mud and sand away from the inside of the sleeve, thereby greatly reducing the amount of mud and sand accumulation.

[0035] The above-mentioned specific embodiments are only specific cases of the present invention. The patent protection scope of the present invention includes but is not limited to the product form and style of the above-mentioned specific embodiments. Any appropriate changes or modifications made to them by ordinary technicians in the relevant technical field in accordance with the claims of the present invention shall fall within the patent protection scope of the present invention.

Claims

1. Large diameter closable staged fracturing sliding sleeve, characterized by: The invention comprises a shell and a closable sliding sleeve arranged in the shell, wherein the two ends of the shell are respectively provided with a detachable upper connecting head and a lower connecting head, and the shell is circumferentially provided with a plurality of evenly distributed fracturing sand intercepting holes at one end close to the upper connecting head, and the lower connecting head comprises a cut-off section and a connecting section connected to the shell, the inner diameter of the cut-off section is smaller than the inner diameter of the connecting section, and a stop lock ring with an outer diameter larger than the inner diameter of the connecting section is provided at the front end of the connecting section, and the inner wall of the stop lock ring is provided with an internal thread, and the closable sliding sleeve is provided with an outer sliding sleeve, an inner sliding sleeve and a soluble valve core in sequence from the outside to the inside, the lower part of the outer sliding sleeve is provided with an external thread matching the internal thread, and the middle part of the inner wall is circumferentially provided with a stop lock ring with an outer diameter larger than the inner diameter of the connecting section. A keyway is provided, and one end of the inner sleeve is provided with a plurality of evenly distributed U-shaped gaps in the circumference, and a key block matching the keyway is provided on the outer wall. The soluble valve core includes a push rod, and the two ends of the push rod are respectively provided with a top block and a slider. The end of the push rod close to the slider is provided with a locking ring, and a shear pin is provided between the locking ring and the push rod. The inner wall of the end of the inner sleeve with the U-shaped gap is provided with a groove for clamping the locking ring; the outer sleeve and the inner sleeve are both provided with a plurality of evenly distributed straight grooves in the circumference, and the straight grooves on the inner sleeve are through-holes running through the inside and outside; the end of the outer sleeve with the straight grooves is provided with a slope angle inside; the outer wall of the inner sleeve is provided with a spiral groove.

2. The large-diameter closable staged fracturing sliding sleeve according to claim 1, characterized in that: The outer sliding sleeve and the inner sliding sleeve are both provided with sealing grooves, and sealing rings are both provided in the sealing grooves.

3. The large-diameter closable staged fracturing sliding sleeve according to claim 1, characterized in that: A wear-resistant layer is provided at the fracturing sand interception hole.

4. The large-diameter closable staged fracturing sliding sleeve according to claim 1, characterized in that: The outer sliding sleeve and the inner sliding sleeve are both made of highly elastic materials.

5. The large-diameter closable staged fracturing sliding sleeve according to claim 4 is characterized in that: The locking ring is C-shaped.

6. The large-diameter closable staged fracturing sliding sleeve according to claim 5, characterized in that: The upper connector and the lower connector are both threadedly connected to the shell.

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