Soluble bridge plug

Abstract

The invention discloses a soluble bridge plug and relates to the technical field of oil field downhole tools. Comprising a center pipe, a boss is arranged on the upper portion of the center pipe, a tool hole used for setting is formed in the boss, a ball seat hole is formed in the boss, the center pipe is sequentially sleeved with a thrust sleeve, a rubber barrel, a propelling sleeve and a slip below the boss, the lower portion of the slip abuts against the upper portion of a guide shoe, and the guide shoe is connected with the center pipe through threads. The well wall soluble bridge plug has the beneficial effects that the fracturing pressure is utilized, after the slips are set, all the slips are driven to expand outwards, and the expansion degree depends on the fracturing pressure instead of being completed by a setting tool in a unified mode, so that the soluble bridge plug has the capacity of adapting to well walls of different specifications, is reliably anchored in the well walls, and is safe and reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oilfield downhole tools, in particular to a soluble bridge plug. BACKGROUND

[0002] The soluble bridge plug is a technical innovation in the field of oil drilling, which is mainly used for controlling water flow in oil and gas wells, especially during hydraulic fracturing operation. Unlike traditional permanent bridge plugs, the bridge plug can dissolve or disappear under certain conditions, thus providing a temporary plugging solution. After drilling, the roughness and irregularity of the well wall may affect the anchoring of the bridge plug's slips, which may not be fully anchored with the irregular well wall when the slips are opened, and the fixing effect may be affected, which may cause loosening or even falling off when the bridge plug bears subsequent pressure. The current soluble bridge plug has a complex structure, resulting in different dissolution efficiencies at different parts, especially the unsealed rubber tube, which causes liquid flow dead angle at the soluble rubber tube part of the bridge plug, and long dissolution time of the bridge plug. SUMMARY

[0003] To solve the problem of the current soluble bridge plug and the unstable anchoring of the drilling well wall, the present application provides a soluble bridge plug.

[0004] The technical scheme provided by the present application is: a soluble bridge plug, comprising a center pipe, a boss is arranged on the upper part of the center pipe, a tool hole for setting is arranged on the boss, a ball seat hole is arranged in the boss, a push sleeve, a rubber tube, a push sleeve and a slip are sequentially sleeved below the boss of the center pipe, the lower part of the slip abuts against the upper part of the guide shoe, and the guide shoe is connected with the center pipe through threads; An opening pin is arranged between the push sleeve and the center pipe, the push sleeve and the center pipe are connected through one-way teeth, the one-way teeth enable the push sleeve to descend along the outer circle of the center pipe and not to ascend, the push sleeve extends downward by a locking sleeve, the rubber tube is sleeved outside the locking sleeve, the locking sleeve extends downward and is inserted into the push sleeve, a step pin is arranged between the push sleeve and the locking sleeve, and the push sleeve is blocked below the rubber tube; A cone is arranged on the lower part of the push sleeve, the push sleeve is pressed on the upper part of the cone, the cone is three in number and is uniformly distributed along the circumference of the center pipe, three blind holes are uniformly distributed on the lower end face of the boss outside the ball seat hole, three circumferential notches are opened on the outer circle of the center pipe, a through hole is opened between the blind hole and the notch, a piston B is arranged in the blind hole, the piston B is gap-fitted with the blind hole through a sealing ring, a top rod is fixedly connected to the lower part of the piston B, and the top rod extends out of the through hole. A retaining ring extends downward from the propulsion sleeve. A large-diameter stepped hole D is opened in the inner hole of the vertebral body. The bottom of the stepped hole D has an annular end surface. A stopper is provided in the notch of the central tube. The outer side of the stopper blocks the annular end surface of the vertebral body. The upper part of the stopper is connected to the lever through the ear plate and the shaft hinge. The inner side of the lever is located at the lower end of the push rod, and the outer side of the lever is located below the retaining ring of the propulsion sleeve. The lower part of the vertebral body is a conical structure with a reduced diameter. The lower part of the vertebral body is inserted into the slips. There are three slips, which are arranged along the outer circumference of the central tube. The inner hole surrounded by the three slips has the same conical hole as the vertebral body. An elastic hoop is covered on the outside of the slips.

[0005] The lower end face of the boss is processed downwardly with a step hole A on the outside of the ball seat hole, and the lower part of the step hole A is processed with a step hole B with a smaller diameter than the step hole A, and the lower part of the step hole B is processed with a step hole C with a smaller diameter than the step hole B. A piston A is provided in the step hole A, and the piston A is clearance-matched with the step hole A through a sealing ring. A compression spring is provided between the piston A and the bottom of the step hole A. The lower part of the piston A is fixedly connected to the valve stem, and the lower part of the valve stem is a conical tip structure. The conical tip of the valve stem is sealed on the step ring surface between the step hole B and the step hole C. An internal opening connected to the inner hole of the center tube is provided on the inside of the step hole C, and an external opening connected to the outer circle of the center tube is provided on the outside of the step hole B. The external opening is located at the one-way tooth connection part between the locking sleeve and the center tube.

[0006] The outer circle of the guide shoe is processed with an annular groove, and a cleaning sleeve is sleeved in the annular groove of the guide shoe. The cleaning sleeve is made of water-absorbing and expanding material.

[0007] There are three circumferentially evenly distributed limiting grooves B on the bottom of the outer circle of the propulsion sleeve. The upper part of the vertebral body is inserted into the inner circumference of the limiting groove B for limiting position. There are three circumferentially evenly distributed limiting grooves A on the upper end face of the guide shoe. The lower part of the slip extends into the inner circumference of the limiting groove A for limiting position.

[0008] The central tube, guide shoe, slip, propulsion sleeve, cone, thrust sleeve, step pin, opening pin, valve stem, piston A, piston B, push rod, stopper, lever, ear plate and shaft are all made of soluble metal, and the elastic hoop and rubber sleeve are made of soluble rubber.

[0009] The beneficial effects of the present application are: 1. The opening pin is arranged, which can prevent the soluble bridge plug from being prematurely set, the rubber sleeve is arranged outside the thrust sleeve, the step pin is arranged between the thrust sleeve and the advancing sleeve, the step-by-step setting is realized, that is, the slip anchor is first anchored, and the rubber sleeve is set in the sequence of setting, so that the surface of the rubber sleeve is not damaged when the action is simultaneously performed, the sealing effect is affected, 2. By utilizing the pressure of fracturing, after the slip is set, each slip is driven to expand outward, and the advancing sleeve does not descend, so that the sealing performance of the rubber sleeve is not damaged, the expansion degree depends on the pressure of fracturing instead of being completed by the setting tool, so that the soluble bridge plug has the ability to adapt to the irregular well wall, is reliably anchored in the well wall, and is safe and reliable, 3. By arranging the switch channel on the wall of the central pipe, the channel between the central pipe and the outside is opened after the fracturing is completed, the liquid in the well flows into the one-way tooth part between the central pipe and the thrust sleeve, the structure size of the one-way tooth is very small, the soluble speed can be accelerated in a short time, the axial constraint between the thrust sleeve and the central pipe is released, each part outside the central pipe is in a free state, the rubber sleeve is retracted under the elasticity of the rubber sleeve, the oil jacket annulus outside the central pipe is filled with liquid, so that the dissolution speed of the whole soluble bridge plug is accelerated. BRIEF DESCRIPTION OF DRAWINGS

[0010] FIG. 1 is a structural schematic diagram of the present application; Figure 1 is a structural schematic diagram of the present application; FIG. 2 is a sectional view of the present application; Figure 2 is a sectional view of the present application; FIG. 3 is an enlarged view of A of the present application; Figure 3 is an enlarged view of A of the present application; Figure 2 FIG. 4 is an enlarged view of B of the present application; is an enlarged view of B of the present application; Figure 4 FIG. 5 is a structural schematic diagram of the central pipe of the present application; Figure 2 is a structural schematic diagram of the central pipe of the present application; is a perspective view of the central pipe of the present application; Figure 5 is a structural schematic diagram of the advancing sleeve of the present application; is a structural schematic diagram of the advancing sleeve of the present application; Figure 6 is a structural schematic diagram of the advancing sleeve of the present application; is a structural schematic diagram of the advancing sleeve of the present application; Figure 7 is a structural schematic diagram of the advancing sleeve of the present application; is a structural schematic diagram of the advancing sleeve of the present application; Figure 8 is a structural schematic diagram of the advancing sleeve of the present application.

[0011] In the figure, 1-center tube, 101-boss, 102-tool hole, 103-ball seat hole, 104-step hole A, 105-step hole B, 106-step hole C, 107-external opening, 108-internal opening, 109-blind hole, 1010-notch, 1011-through hole, 2-guide shoe, 201-limiting groove A, 3-slip, 4-rubber cylinder, 5-propelling sleeve, 501-limiting groove B, 502-retaining ring, 6-thrust sleeve, 601-locking sleeve, 7-stepping pin, 8-cleaning sleeve, 9-one-way tooth, 10-valve stem, 11-piston A, 12-elastic hoop, 13-vertebral body, 1301-step hole D, 1302-annular end face, 14-opening pin, 15-soluble ball, 16-piston B, 17-top rod, 18-stopper, 19-lever, 20-shaft, 21-ear plate. DETAILED DESCRIPTION

[0012] like Figures 1 to 8 As shown, a soluble bridge plug includes a center tube 1, a boss 101 is provided on the upper portion of the center tube 1, a tool hole 102 for setting the seal is provided on the boss 101, a ball seat hole 103 is provided in the boss 101, and a thrust sleeve 6, a rubber sleeve 4, a propulsion sleeve 5, and a slip 3 are sequentially mounted on the center tube 1 below the boss 101. The lower portion of the slip 3 abuts against the upper portion of the guide shoe 2, and the guide shoe 2 is connected to the center tube 1 via threads. An opening pin 14 is provided between the thrust sleeve 6 and the center tube 1 to prevent the soluble bridge plug from being set prematurely. The thrust sleeve 6 and the center tube 1 are connected by a one-way tooth 9, which allows the thrust sleeve 6 to descend along the outer circle of the center tube 1 but not to rise. The thrust sleeve 6 extends downward to form a locking sleeve 601. The rubber cylinder 4 is sleeved on the outside of the locking sleeve 601. The locking sleeve 601 extends downward to be inserted into the propulsion sleeve 5. A stepping pin 7 is provided between the propulsion sleeve 5 and the locking sleeve 601. The propulsion sleeve 5 is blocked under the rubber cylinder 4. A cone 13 is provided at the lower portion of the propulsion sleeve 5, and the propulsion sleeve 5 is pressed on the cone 13. There are three cones 13 evenly distributed along the circumference of the center tube 1. The lower end surface of the boss 101 is processed downwardly from the outer side of the ball seat hole 103 with three evenly distributed blind holes 109. The outer circle of the center tube 1 is opened with three evenly distributed notches 1010. A through hole 1011 is opened between the blind holes 109 and the notches 1010. A piston B16 is provided in the blind hole 109. The piston B16 is fitted into the blind hole 109 through a sealing ring clearance. The lower part of the piston B16 is fixedly connected to the push rod 17, and the push rod 17 extends out of the through hole 1011. The advancing sleeve 5 extends downwardly by a stop ring 502, the inner hole of the body 13 is provided with a stepped hole D1301 of large diameter, the bottom of the stepped hole D1301 is provided with an annular end face 1302, the notch 1010 of the central pipe 1 is provided with a stop block 18, the outer side of the stop block 18 is stopped on the annular end face 1302 of the body 13, the upper part of the stop block 18 is hingedly connected to the lever 19 through the ear plate 21 and the shaft 20, the inner side of the lever 19 is located below the lower end of the top rod 17, and the outer side of the lever 19 is located below the stop ring 502 of the advancing sleeve 5. The lower part of the body 13 is a conical structure with a reduced diameter, the body 13 is inserted into the slips 3, the number of the slips 3 is three, the slips 3 are arranged along the outer side of the central pipe 1, the inner hole surrounded by the three slips 3 has the same conical hole as the body 13, and the outer side of the slip 3 is sleeved with the elastic hoop 12.

[0013] When the soluble bridge plug is set, the setting tool limits the downward movement of the guide shoe 2, and the pushing sleeve 6 is pushed downward, the opening pin 14 is cut off, since the step pin 7 is arranged between the advancing sleeve 5 and the pushing sleeve 6, the advancing sleeve 5 and the pushing sleeve 6 cannot move up and down, the advancing sleeve 5 pushes the body 13 to move downward, the body 13 pushes the slip 3 to expand outward and anchor in the casing, the setting tool continues to press, the step pin 7 is cut off, the pushing sleeve 6 moves downward to be close to the advancing sleeve 5, the pushing sleeve 6 cannot rise again under the action of the one-way tooth 9, and the rubber cylinder 4 is pressed and expanded to be attached to the inner wall of the casing to be sealed.

[0014] The opening pin 14 is arranged to prevent the soluble bridge plug from being set too early, the rubber cylinder 4 is arranged outside the pushing sleeve 6, the step pin 7 is arranged between the pushing sleeve 6 and the advancing sleeve 5, the step-by-step setting is realized, that is, the slip 3 is anchored first, and the rubber cylinder 4 is set later, the sequence action is avoided, the surface of the rubber cylinder 4 is not pulled and damaged, and the sealing effect is affected.

[0015] After the soluble bridge plug is set, the soluble ball 15 is put into the soluble bridge plug, the soluble ball 15 falls on the ball seat hole 103 to be sealed, so as to separate the upper and lower parts of the soluble bridge plug, the pressure of fracturing makes the piston B16 move downward, the piston B16 and the top rod 17 move downward to press against the inner side of the lever 19, so that the stop block 18 moves downward, and the outer side of the lever 19 moves upward to stop the advancing sleeve 5 from moving downward, the stop block 18 moves downward to push the body 13 to move downward. Since one stop block 18 is arranged on each body 13, the pressure of fracturing can drive the stop block 18 to move downward to push the body 13 to move downward, when the anchoring force of the slip 3 to the well wall is not enough, the pressure of fracturing can push the body 13 to move downward to anchor the slip 3 to the well wall, by using the pressure of fracturing, after the slip 3 is set, each slip 3 is driven to expand outward, the expansion degree depends on the pressure of fracturing instead of being completed by the setting tool uniformly, so that the soluble bridge plug has the ability to adapt to the irregular well wall, and can be reliably anchored in the well wall, which is safe and reliable.

[0016] The lower end face of the boss 101 is downwardly machined with a stepped hole A 104 outside the ball seat hole 103, the lower part of the stepped hole A 104 is machined with a stepped hole B 105 smaller in diameter than the stepped hole A 104, the lower part of the stepped hole B 105 is machined with a stepped hole C 106 smaller in diameter than the stepped hole B 105, the stepped hole A 104 is provided with a piston A 11, the piston A 11 is in clearance fit with the stepped hole A 104 through a sealing ring, a compression spring is arranged between the piston A and the bottom of the stepped hole A 104, the lower part of the piston A 11 is fixedly connected with a valve rod 10, the lower part of the valve rod 10 is in conical pointed structure, the conical pointed head of the valve rod 10 is in sealing with the stepped annular surface between the stepped hole B 105 and the stepped hole C 106, the inner side of the stepped hole C 106 is provided with an inner through hole 108 in communication with the inner hole of the central pipe 1, the outer side of the stepped hole B 105 is provided with an outer through hole 107 in communication with the outer circle of the central pipe 1, and the outer through hole 107 is located at the connection position of the locking sleeve 601 and the one-way tooth 9 of the central pipe 1.

[0017] During fracturing, the pressure of fracturing makes the piston A 11 descend, the valve rod 10 closes the inner and outer passages of the central pipe 1, when the pressure above is released at the end of fracturing, no matter whether the soluble ball 15 is separated from the ball seat hole 103 or not, the piston A 11 rises under the action of the compression spring, the inner and outer passages of the central pipe 1 are opened, the liquid in the well flows into the one-way tooth 9 part between the central pipe 1 and the thrust sleeve 6, since the structure size of the one-way tooth 9 is very small, it can be dissolved in a short time, the upward and downward direction restraint between the thrust sleeve 6 and the central pipe 1 is released, each part outside the central pipe 1 is in free state, the rubber sleeve 4 is retracted under the elasticity of itself, the oil jacket annulus outside the central pipe 1 can be filled with liquid, thereby accelerating the dissolution speed of the whole soluble bridge plug The outer circle of the guide shoe 2 is machined with an annular groove, the guide shoe 2 is sleeved with a cleaning sleeve 8 in the annular groove, the cleaning sleeve 8 is made of water-absorbing and expanding material, can clean the inner wall of the casing, improve the anchoring force and sealing effect.

[0018] The outer circle of the thrust sleeve 5 is opened with three circumferentially distributed limiting grooves B 501 at the bottom, the upper part of the vertebra 13 is inserted into the circumferential limiting of the limiting grooves B 501, the upper end face of the guide shoe 2 is opened with three circumferentially distributed limiting grooves A 201, the lower part of the slip 3 is inserted into the circumferential limiting of the limiting grooves A 201.

[0019] The central pipe 1, the guide shoe 2, the slip 3, the thrust sleeve 5, the vertebra 13, the thrust sleeve 6, the step pin 7, the opening pin 14, the valve rod 10, the piston A 11, the piston B 16, the jacking rod 17, the stop block 18, the lever 19, the ear plate 21 and the shaft 20 are all made of soluble metal, and the elastic hoop 12 and the rubber sleeve 4 are made of soluble rubber.

Claims

1. A soluble bridge plug, comprising a central tube (1), characterized in that: A boss (101) is provided on the upper part of the center tube (1), a tool hole (102) for setting a seal is provided on the boss (101), a ball seat hole (103) is provided in the boss (101), and a thrust sleeve (6), a rubber sleeve (4), a propulsion sleeve (5) and a slip (3) are sequentially sleeved on the center tube (1) below the boss (101), the lower part of the slip (3) abuts against the upper part of the guide shoe (2), and the guide shoe (2) is connected to the center tube (1) through a thread. An opening pin (14) is provided between the thrust sleeve (6) and the center tube (1). The thrust sleeve (6) and the center tube (1) are connected via a one-way tooth (9). The one-way tooth (9) enables the thrust sleeve (6) to descend along the outer circle of the center tube (1) but not to ascend. The thrust sleeve (6) extends downward to form a locking sleeve (601). The rubber cylinder (4) is sleeved on the outside of the locking sleeve (601). The locking sleeve (601) extends downward to be inserted into the propulsion sleeve (5). A stepping pin (7) is provided between the propulsion sleeve (5) and the locking sleeve (601). The propulsion sleeve (5) is blocked below the rubber cylinder (4). The lower part of the propulsion sleeve (5) is provided with a cone (13), and the propulsion sleeve (5) is pressed on the cone (13). The cone (13) is evenly distributed along the circumference of the center tube (1). The lower end surface of the boss (101) is processed downwardly on the outer side of the ball seat hole (103) with three evenly distributed blind holes (109). The outer circle of the center tube (1) is provided with three evenly distributed notches (1010). A through hole (1011) is provided between the blind hole (109) and the notch (1010). A piston B (16) is provided in the blind hole (109). The piston B (16) is fitted with the blind hole (109) through the gap of the sealing ring. The lower part of the piston B (16) is fixedly connected to the push rod (17), and the push rod (17) extends out of the through hole (1011). The propulsion sleeve (5) extends downwardly through a retaining ring (502), the inner hole of the vertebral body (13) is provided with a stepped hole D (1301) with a large diameter, the bottom of the stepped hole D (1301) has an annular end surface (1302), a stopper (18) is provided in the notch (1010) of the central tube (1), the outer side of the stopper (18) is blocked on the annular end surface (1302) of the vertebral body (13), the upper part of the stopper (18) is hingedly connected to the lever (19) through the ear plate (21) and the shaft (20), the inner side of the lever (19) is located at the lower end of the push rod (17), and the outer side of the lever (19) is located below the retaining ring (502) of the propulsion sleeve (5); The lower part of the vertebral body (13) is a conical structure with a reduced diameter. The lower part of the vertebral body (13) is inserted into the slips (3). The number of the slips (3) is three. The slips (3) are arranged along the outer circumference of the central tube (1). The inner hole surrounded by the three slips (3) has the same conical hole as the vertebral body (13). The outer side of the slips (3) is covered with an elastic hoop (12).

2. The soluble bridge plug according to claim 1, characterized in that: The lower end surface of the boss (101) is processed downwardly with a step hole A (104) outside the ball seat hole (103), the lower part of the step hole A (104) is processed with a step hole B (105) with a smaller diameter than the step hole A (104), the lower part of the step hole B (105) is processed with a step hole C (106) with a smaller diameter than the step hole B (105), a piston A (11) is provided in the step hole A (104), the piston A (11) is clearance-matched with the step hole A (104) through a sealing ring, and a compression spring is provided between the piston A (11) and the bottom of the step hole A (104). The lower part of the piston A (11) is fixedly connected to the valve stem (10). The lower part of the valve stem (10) is a conical tip structure. The conical tip of the valve stem (10) is sealed on the step ring surface between the step hole B (105) and the step hole C (106). The inner side of the step hole C (106) is provided with an inner opening (108) connected to the inner hole of the center tube (1). The outer side of the step hole B (105) is provided with an outer opening (107) connected to the outer circle of the center tube (1). The outer opening (107) is located at the connection part of the one-way tooth (9) of the locking sleeve (601) and the center tube (1).

3. The soluble bridge plug according to claim 1, characterized in that: The outer circle of the guide shoe (2) is processed with an annular groove, and a cleaning sleeve (8) is sleeved in the annular groove of the guide shoe (2). The cleaning sleeve (8) is made of water-absorbing and expanding material.

4. The soluble bridge plug according to claim 1, characterized in that: The outer bottom of the propulsion sleeve (5) is provided with three circumferentially evenly distributed limiting grooves B (501), the upper part of the vertebral body (13) is inserted into the inner circumference of the limiting groove B (501) for limiting position, the upper end surface of the guide shoe (2) is provided with three circumferentially evenly distributed limiting grooves A (201), and the lower part of the slip (3) is extended into the inner circumference of the limiting groove A (201) for limiting position.

5. A soluble bridge plug according to claim 1, 2 or 3, characterized in that: The central tube (1), guide shoe (2), slip (3), propulsion sleeve (5), vertebral body (13), thrust sleeve (6), stepping pin (7), opening pin (14), valve stem (10), piston A (11), piston B (16), push rod (17), stopper (18), lever (19), ear plate (21) and shaft (20) are all made of soluble metal, and the elastic hoop (12) and rubber sleeve (4) are made of soluble rubber.

Images