Shale gas casing variable diameter well staged fracturing 65 mm outside diameter expanded to 114.3 mm bridge plug slip

Abstract

The application discloses a bridge plug slip of 65mm outer diameter expansion to 114.3mm for shale gas casing deformation well segmented fracturing, which comprises a tailstock, double-inclined-plane push block groups, a slip base, a slip push block, a slip tooth, a center rod, a fixed pin, a starting pin, a thrust block and a limiter. In the anchoring process, the two groups of double-inclined-plane push block groups are symmetrically arranged on the left and right sides of the slip base, the slip push block moves downward along the center rod, drives the two groups of double-inclined-plane push block groups to produce radial displacement, when the wedge-shaped block in the double-inclined-plane push block reaches the maximum displacement in the wedge-shaped groove of the slip base, the slip base and the right double-inclined-plane push block group simultaneously displace downward, drives the slip base to produce radial displacement, until the slip tooth is anchored stably with the casing, the limiting elastic block is bounced into the center rod, preventing the slip base from rebounding. The bridge plug slip is expanded from the initial outer diameter of 65mm to a large range of 114.3mm, the anchoring of the slip is stable and reliable, and the bridge plug can smoothly pass through when the casing is severely deformed in the fracturing operation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of downhole tools for oil and gas, shale gas fracturing, in particular to a 65mm outer diameter expanded 114.3mm bridge plug slip for shale gas casing deformation well staged fracturing. BACKGROUND

[0002] Shale gas, as a kind of unconventional natural gas, is widely distributed and has great development potential. Compared with conventional oil and gas resources, it is difficult to exploit and has low exploitation efficiency. At present, large-scale volume fracturing is mainly used to achieve the purpose of yield improvement. At the same time, due to the large scale of fracturing, casing deformation frequently occurs. Bridge plug is one of the important tools for fracturing operation. Compared with traditional bridge plug, soluble bridge plug can be used for temporary plugging of oil, gas and water layers, and is used for multilayer fracturing of horizontal wells and vertical wells. Advanced degradable metal and rubber materials are used to realize complete degradation of the bridge plug, help users reduce the use risk, and do not need to drill the plug with coiled tubing, thereby reducing the cost of coiled tubing operation. At present, the minimum outer diameter of soluble bridge plug is only 83mm. In the horizontal well fracturing or after fracturing, when the casing is severely deformed due to shrinkage, the bridge plug cannot pass through the casing deformation position, and cannot be pumped to the predetermined design position for effective staged reconstruction, which seriously hinders the rapid production of gas wells. SUMMARY

[0003] The purpose of the present application is to design a 65mm outer diameter expanded 114.3mm bridge plug slip for shale gas casing deformation well staged fracturing, so that it can smoothly pass through the casing when the casing is severely deformed due to shrinkage, and can be stably anchored on the casing after the slip is greatly deformed and expanded. At the same time, after the fracturing operation is completed, the bridge plug can be completely dissolved, and the wellbore full bore can be rapidly put into production.

[0004] The technical scheme of the present application is: the bridge plug slip of the shale gas casing variable diameter well staged fracturing is expanded from 65mm to 114.3mm, which comprises a tailstock, a double-bevel push block group, a slip group, a slip push block, a slip tooth, a center rod, a fixed pin, a starting pin, a thrust block, a limiting spring block and a limiting top cover. The center rod is provided with a limiting groove in the middle part and a starting pin hole in the right part, and the tailstock is connected with the center rod by bolts. The slip tooth is embedded in the slip group, and the two double-bevel push block groups are symmetrically arranged on the left and right sides of the slip group. The tailstock, the left double-bevel push block group, the right double-bevel push block group and the slip push block are all connected by protruding wedge blocks and wedge grooves and are seated on the center rod. Each wedge groove is provided with a thrust block at the top and is connected and fixed by a fixed pin shaft. The tailstock is provided with a starting pin, which is inserted into the slip push block and the center rod before anchoring to limit the axial movement of the tailstock and prevent the slip from anchoring too early. The limiting spring block and the limiting top cover are arranged in the same plane with the starting pin in the tailstock. Before the slip is anchored, the limiting spring block is compressed in the center rod and the limiting top cover. The limiting top cover is axially connected with the tailstock by bolts. When the starting pin in the slip push block is cut off, the slip push block moves downward along the center rod, drives the two double-bevel push block groups to produce radial displacement and drives the slip group to produce partial radial displacement. When the wedge block in the double-bevel push block reaches the maximum displacement in the wedge groove of the slip group, the slip group and the right double-bevel push block group are displaced downward at the same time, which drives the slip group to continue to produce radial displacement until the slip tooth is anchored stably with the casing. The limiter spring is inserted into the limiting groove on the center rod to prevent the slip group from rebounding, realizing the large-range variable-diameter expansion of the anchoring device from the initial outer diameter of 65mm to 114.3mm. After the fracturing operation is completed, the metal part of the slip is dissolved.

[0005] The left end of the center rod is a threaded part, which is connected with the tailstock to fix the tailstock on the center rod and limit the circumferential rotation of the bridge plug anchoring device. The middle part is provided with a rectangular limiting groove, and the right part is provided with a starting pin hole. The starting pin is inserted into the hole before anchoring to prevent the slip from anchoring too early.

[0006] The slip group is a split single slip structure. Since the outer diameter of the bridge plug is 65mm, the slip is distributed in the axial direction for four times. The slip is long and is matched with the wedge blocks on the center rod through the wedge blocks on the two sides of the slip group and the wedge grooves of the double-bevel push blocks on the two sides. The slip push block moves downward, drives the double-bevel push blocks on the left and right sides and the slip group to move downward and produce radial displacement, and quickly engages into the casing wall to complete anchoring. The slip group is composed of magnesium-aluminum soluble alloy material, and the slip teeth are uniformly embedded on the left and right sides. The slip teeth are designed in a sheet-shaped tooth structure and are made of ceramic material, which can improve the reliability of the slip anchoring and facilitate flowback.

[0007] The tail seat and the slip push block are made of magnesium-aluminum soluble alloy material, the tail seat is connected with the central rod by screw thread, is stable and reliable, can constrain the circumferential rotation of the whole anchoring device, and the tail seat and the slip push block have four inclined surfaces and wedge grooves on one side, so that the two-side double-inclined push block can be stably moved on the inclined surface, the wedge groove end is equipped with a thrust block and is fixed by a fixed pin, the double-inclined push block group is prevented from being separated, the tail seat end is a hexagonal boss, which is convenient for assembly, the starting pin is assembled in the slip push block by interference fit, the slip is prevented from being anchored in advance, the limiting elastic block and the limiting top cover are arranged in the tail seat and are in the same plane with the starting pin, before the slip is anchored, the limiting elastic block is compressed in the central rod and the limiting top cover, and the limiting top cover is connected with the tail seat by axial bolt.

[0008] The double-inclined push block group has four on the left and right sides respectively, the cooperation surface with the slip group is a wedge groove, and the cooperation surface with the tail seat and the slip push block is a protruding wedge block, and the wedge groove end is equipped with a thrust block and a fixed pin.

[0009] The beneficial effects of the present application are:

[0010] 1) The bridge plug slip of the present application has an outer diameter of 65mm, which is smaller than the existing soluble bridge plug, and does not need to consider the continuous oil pipe, so that the technical problem of no available separation tool due to serious casing deformation in the fracturing operation can be effectively solved.

[0011] 2) The slip group designed in the present application is a split type single slip group structure, since the bridge plug has an outer diameter of 65mm, the slip is distributed in the axial direction for 4, the slip length is relatively long, and the wedge block on the two sides of the slip group is matched with the wedge groove of the two-side double-inclined push block on the central rod, the slip push block descends, drives the left and right two-side double-inclined push block and the slip group to descend and generate radial displacement, and quickly engages into the casing wall to complete anchoring. The slip group is made of magnesium-aluminum soluble alloy material, and the left and right are uniformly embedded with slip teeth, the slip teeth are designed as a sheet-shaped tooth structure, and are made of ceramic material, which can improve the reliability of the slip anchoring and facilitate flowback.

[0012] 3) The bridge plug slip of the present application does not need to drill the plug, saves the time and cost caused by bridge plug drilling and grinding, is easy to flow back, and can quickly put into production after the dissolution is completed. BRIEF DESCRIPTION OF DRAWINGS

[0013] The present application will be described by means of the accompanying drawings, in which:

[0014] Figure 1 is a schematic diagram of the overall structure of the bridge plug slip with an outer diameter of 65mm after expansion to 114.3mm for the shale gas casing deformation well staged fracturing.

[0015] Figure 2It is the overall structure sectional view of the bridge plug slip of shale gas casing variable well staged fracturing of the present application with the outer diameter of 65mm after expansion of 114.3mm

[0016] Figure 3 It is Figure 1 The structure schematic diagram of the anchor of the middle slip group.

[0017] In the figure, 1 is a tail seat, 2 is a fixed pin, 3 is a thrust block, 4 is a center rod, 41 is a threaded joint, 42 is a limiting groove, 43 is a starting pin hole, 5 is a right side double bevel push block, 51 is a wedge-shaped protrusion, 52 is a wedge-shaped groove, 6 is a slip group, 61 is a wedge-shaped protrusion, 7 is a slip tooth, 8 is a left side double bevel push block, 9 is a slip push block, 10 is a starting pin, 11 is a limiting top cover, 12 is a limiting elastic block, and 13 is an M4 internal hexagonal bolt. DETAILED DESCRIPTION

[0018] The present application is further described below in combination with the drawings and examples.

[0019] As Figure 1 , Figure 2 , Figure 3 shown, the bridge plug slip of shale gas casing variable well staged fracturing of the present application with the outer diameter of 65mm after expansion of 114.3mm, comprising a tail seat 1, a left side double bevel push block group 5, a right side double bevel push block group 8, a slip group 6, a slip push block 9, also comprising a slip tooth 7, a center rod 4, a fixed pin 2, a starting pin 10, a thrust block 3, and a limiting elastic block 12 and a limiting top cover 11. The center rod 4 is provided with a limiting groove 42 in the middle part, and a starting pin hole 43 is provided at the right side part. The tail seat 1 is connected with the center rod 4 by a bolt, the slip tooth 7 is embedded into the slip group 6, and the two groups of double bevel push blocks are symmetrically arranged on the left and right sides of the slip group. The tail seat, the left side double bevel push block group, the left side double bevel push block group, the slip group, the slip group, the right side double bevel push block group, and the right side double bevel push block group are all connected and seated on the center rod 4 by the cooperation of the protruding wedge-shaped protrusions 51 and the wedge-shaped grooves 52. Each wedge-shaped groove is provided with a thrust block 3 at the top and is connected and fixed by a fixed pin shaft 2. The tail seat is provided with a starting pin 10. Before anchoring, the starting pin 10 is radially inserted into the slip push block 9 and the center rod 4, limiting the axial movement of the tail seat 1 and preventing the slip from anchoring in advance. The limiting elastic block 12 and the limiting top cover 11 are also provided in the tail seat 1 in the same plane as the starting pin 10. Before the slip is anchored, the limiting elastic block 12 is compressed in the center rod 4 and the limiting top cover 11. The limiting top cover 11 is connected with the tail seat 1 by an axial M4 internal hexagonal bolt 13.

[0020] The working principle of the bridge plug slip of the shale gas casing variable well staged fracturing of the present application with the outer diameter of 65 mm expanded to 114.3 mm is that, in use, the bridge plug is pumped to the predetermined position by the cable, the high-pressure gas is filled in the combustion chamber by igniting the fire powder through the cable, the setting push cylinder is pushed by the high-pressure gas in the setting tool, the starting pin 10 in the slip block 6 is sheared off, the slip block 6 moves downward along the center rod 4, the radial displacement of the two groups of double-inclined-surface push block groups 5 and 8 is generated and the partial radial displacement of the slip block groups 6 and 7 is generated, when the wedge-shaped protrusions 51 in the double-inclined-surface push block groups 5 and 8 reach the maximum displacement amount in the wedge-shaped grooves 52 of the slip block groups, the slip block group 6 and the right double-inclined-surface push block group 5 are displaced downward at the same time, the radial displacement of the slip block group 6 is continuously generated, until the slip teeth 7 are anchored stably with the casing, the limiting elastic block 12 is in the limiting groove 42 on the center rod 4, the slip block group 6 is prevented from rebounding, the anchoring device is expanded from the initial outer diameter of 65 mm to the large-range variable-diameter expansion of 114.3 mm, and the bridge plug metal part is dissolved after the fracturing operation is completed. The anchoring device metal part is completely dissolved after the fracturing operation is completed.

[0021] Embodiment:

[0022] As shown in Figure 1 , Figure 2 , the bridge plug slip of the shale gas casing variable well staged fracturing of the present application with the outer diameter of 65 mm expanded to 114.3 mm comprises a tail seat 1, a left double-inclined-surface push block group 5, a right double-inclined-surface push block group 8, a slip block group 6, a slip block 9, a slip tooth 7, a center rod 4, a fixed pin 2, a starting pin 10, a thrust block 3, a limiting elastic block 12 and a limiting top cover 11. The center rod 4 is provided with the limiting groove 42 in the middle part and the starting pin hole 43 in the right side part, the tail seat 1 is connected with the center rod 4 by bolts, the slip tooth 7 is embedded in the slip block group 6, the two groups of double-inclined-surface push block groups are symmetrically arranged on the left and right sides of the slip block group, the tail seat, the left double-inclined-surface push block group, the left double-inclined-surface push block group and the slip block group, the slip block group and the right double-inclined-surface push block group, and the right double-inclined-surface push block group and the slip block are all connected by the protruding wedge-shaped protrusions 51 and the wedge-shaped grooves 52 and are seated on the center rod 4, each wedge-shaped groove is provided with the thrust block 3 at the top and is connected and fixed by the fixed pin shaft 2, the starting pin 10 is arranged in the tail seat and is radially inserted into the slip block 9 and the center rod 4 before anchoring, the axial movement of the tail seat 1 is limited, the slip block is prevented from being anchored in advance, the limiting elastic block 12 and the limiting top cover 11 are arranged in the tail seat 1 and are in the same plane with the starting pin 10, the limiting elastic block 12 is compressed in the center rod 4 and the limiting top cover 11 before the slip block is anchored, and the limiting top cover 11 is connected with the tail seat 1 by the axial M4 internal hexagonal bolt 13.

[0023] As shown in Figure 1 , Figure 3As shown, the tailstock 1, the slip pusher 9, and the double-sloped slip pushers 5 and 8 are all made of magnesium-aluminum soluble alloy. The tailstock 1 is connected to the center rod 4 by a thread, which is stable and reliable and can constrain the circumferential rotation of the overall anchoring device. The tailstock 1 and the slip pusher 9 each have four slopes and wedge grooves 52 on one side, which allows the double-sloped pushers on both sides to move stably on the slopes. The ends of the wedge grooves are equipped with thrust blocks 3 and fixed with fixing pins 2 to prevent the double-sloped pusher assemblies 5 and 8 from disengaging. The end of the tailstock 1 is a hexagonal boss for easy assembly. The starting pin 10 is assembled in the slip pusher 9 by an interference fit to prevent the slip from anchoring prematurely. The limiting spring block 12 and the limiting top cover 11 are also set in the tailstock 1 on the same plane as the starting pin 10. Before the slip is anchored, the limiting spring block 12 is compressed in the center rod 4 and the limiting top cover 11. The limiting top cover 11 is connected to the tailstock 1 by an axial M4 internal hex bolt 13. Tailstock 1 can be machined with threaded bosses or threaded holes to connect with the actual sealing device, depending on the working conditions.

[0024] like Figure 3 As shown, the slip assembly is a segmented single slip assembly structure. Since the bridge plug outer diameter is 65mm, four slips are distributed axially. The slips are relatively long and are connected to the central rod via wedge-shaped protrusions 51 on both sides of the slip assembly 6 and wedge-shaped grooves 52 on the double-sloping push blocks on both sides. When the slip push block 9 moves downwards, it drives the double-sloping push blocks 5 and 8 on both sides and the slip assembly 6 downwards, generating radial displacement and quickly engaging the sleeve wall to complete anchoring. The slip assembly is made of a magnesium-aluminum soluble alloy material, with slip teeth evenly embedded on both sides. The slip teeth are designed as a plate-like tooth structure made of ceramic material, which improves the reliability of slip anchoring and facilitates re-extraction.

[0025] The ingenious aspect of this technology lies in the fact that the outer diameter of the bridge plug slip is 65mm, allowing it to pass smoothly even when the casing undergoes severe diameter reduction deformation during fracturing operations, without needing to consider the installation of coiled tubing. The slip assembly is a segmented single slip assembly structure with a relatively long length. Slip assembly 6 engages with the left and right double-inclined push block assemblies 5 and 8 via a wedge groove 52. The left and right double-inclined push blocks 5 and 8 also engage with the tailstock 1 and slip push block 9 via wedge grooves 52 and wedge protrusions 51, respectively. Through compression, the double-inclined push blocks 5 and 8 are displaced on the inclined surface of slip push block 9, causing partial radial displacement of the slip assembly. When the double-inclined push blocks 5 and 8 reach their maximum displacement on the inclined surface of the slip push block, they continue to drive slip assembly 6, causing it to displace on the other inclined surface of the double-inclined push block, and finally, slip assembly 6 reaches its maximum radial displacement and is stably anchored to the casing. The anchoring device design allows for a wider range of diameter changes in the slips, while also providing the reliability and stability of rivets. It eliminates the need for drilling plug operations, saving time and costs associated with bridge plug drilling and grinding. It is easy to return the slips to the wellbore and allows for rapid production across the entire bore after dissolution.

[0026] In the description of the application, it should be understood that if there are orientation or positional relationships indicated by terms such as top, bottom, left, right, inner, outer, radial, etc., the orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary description, and cannot be understood as a limitation on the patent.

[0027] The above-described embodiments only express the specific implementation of the present application, which is described in detail, but cannot be understood as a limitation on the protection scope of the present application. It should be pointed out that for ordinary skilled persons in the art, without departing from the technical concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application.

Claims

1. A bridge plug slip for shale gas casing collar variable well staged fracturing with an outer diameter of 65 mm after expansion to 114.3 mm, comprising a tailstock (1), two sets of double-bevel push block groups (5, 8), a slip group (6), a slip push block (9), further comprising a slip tooth (7), a center rod (4), a fixed pin (2), a starting pin (10), a thrust block (3), a limiting elastic block (12) and a limiting top cover (11); the center rod (4) is provided with a limiting groove (42) in the middle part and a starting pin hole (43) in the right part, the tailstock (1) is connected with the center rod (4) by bolts, the slip tooth (7) is embedded into the slip group (6), the two sets of double-bevel push block groups are symmetrically arranged on the left and right sides of the slip group, the tailstock (1), the left double-bevel push block group (5), the slip group, the right double-bevel push block group (8) and the slip push block (9) are all connected by wedge-shaped blocks (51) and wedge-shaped grooves (52) and are seated on the center rod (4), each wedge-shaped groove is provided with a thrust block (3) at the top and is connected and fixed by a fixed pin (2), the tailstock (1) is provided with a starting pin (10), before anchoring, the starting pin (10) is radially inserted into the slip push block (9) and the center rod (4) to limit the axial movement of the tailstock (1) and prevent the slip from anchoring too early, the limiting elastic block (12) and the limiting top cover (11) are also arranged in the same plane with the starting pin (10) in the tailstock (1), before the slip is anchored, the limiting elastic block (12) is compressed in the center rod (4) and the limiting top cover (11), the limiting top cover (11) is connected with the tailstock (1) by an axial M4 internal hexagonal bolt (13); as the starting pin (10) in the slip push block (9) is cut off, the slip push block (9) moves downward along the center rod (4), drives the two sets of double-bevel push block groups to produce radial displacement and drives the slip group to produce partial radial displacement, when the wedge-shaped blocks in the double-bevel push block groups reach the maximum displacement in the wedge-shaped grooves of the slip group (6), the slip group (6) and the right double-bevel push block group (8) are displaced downward at the same time, which drives the slip group (6) to continue to produce radial displacement until the slip tooth (7) is anchored stably with the casing, the limiting elastic block (12) is elastically inserted into the limiting groove (42) on the center rod (4) to prevent the slip group (6) from rebounding, realizing the large-range variable expansion of the slip from the initial outer diameter of 65 mm to 114.3 mm, and the metal part of the slip is dissolved after the fracturing operation is completed; the slip group (6) is a split single slip group structure, as the outer diameter of the bridge plug slip is 65 mm, the slip is distributed in four parts along the axial direction, the slip length is relatively long, the slip push block (9) moves downward, drives the left and right double-bevel push block groups and the slip group (6) to move downward and produce radial displacement, and quickly engages into the casing wall to complete anchoring; the slip group (6) is composed of magnesium-aluminum soluble alloy material, the slip teeth are evenly embedded on the left and right sides, the slip tooth (7) is designed in a sheet-shaped tooth structure and is made of ceramic material.

2. The 65 mm outer diameter expanded to 114.3 mm bridge plug slip of a staged fracturing of a shale gas casing change well according to claim 1, characterized in that, The tail seat (1), two groups of double-inclined surface pushing block groups (5, 8) and the wedge-shaped groove top of the slip pushing block (9) are provided with a thrust block (3) and are connected and fixed by a fixed pin (2), so that the bridge plug slip has stability as a whole.

3. The 65 mm OD expanded to 114.3 mm bridge plug slip of the staged fracturing of shale gas cased well according to claim 1, characterized in that, The limiting elastic block (12) is connected with a rectangular spring, the elastic force meets the requirement of the elastic block being elastically inserted into the center rod limiting groove, the bridge plug slip is prevented from rebounding after anchoring, and the anchoring of the bridge plug slip is reliable and stable.

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