Soluble bridge plug for fracturing

Abstract

The invention discloses a soluble bridge plug for fracturing, and relates to the technical field of oil field downhole tools. Flushing holes arranged up and down are formed in the lower portion of the outer circle of the blasting cleaning cylinder and evenly distributed along the circumference of the outer circle of the blasting cleaning cylinder, stepped holes with the reduced diameter are machined in the outer sides of the flushing holes, and glass sheets are bonded to the flushing holes in the inner sides of the stepped holes in a sealed mode. The blasting cleaning device has the beneficial effects that the blasting cleaning barrel is arranged on the lower side of the rubber barrel, blasting is triggered through the action of the propelling sleeve, blasting powder pushes a piston to descend at a high speed through high-pressure and high-impact waves, cleaning liquid is extruded to crush glass sheets, and the high-speed cleaning liquid flushes the inner wall of a sleeve; and then the rubber sleeve descends to the cleaned sleeve part, the rubber sleeve wipes the cleaned part while expanding, and through the technical means, the setting force of the soluble bridge plug is improved, the compression strength of the soluble bridge plug is improved, and smooth fracturing operation is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of oilfield downhole tools technology, and in particular to a soluble bridge plug for fracturing. Background Technology

[0002] Soluble bridge plugs are a technological innovation in the field of oil drilling. They are mainly used to control water flow in oil and gas wells, especially during hydraulic fracturing operations. Unlike traditional permanent bridge plugs, these bridge plugs can dissolve or disappear under certain conditions, thus providing a temporary sealing solution.

[0003] Fracturing for increased production is carried out in the later stages of oilfield production. Scale, rust and other impurities will accumulate on the inner wall of the casing downhole, causing the rubber sleeve to not fit tightly against the inner wall of the casing. It is difficult to achieve a complete seal by squeezing only the annular surface of the rubber sleeve. The dirty oil adhering to the inner wall of the casing is also not conducive to the sealing of the rubber sleeve, and the pressure resistance of the rubber sleeve is insufficient. Summary of the Invention

[0004] To address the problems of poor sealing and low pressure resistance of existing soluble bridge plugs used in fracturing for increased production, this invention provides a soluble bridge plug for fracturing.

[0005] The technical solution provided by this invention is: a soluble bridge plug for fracturing, comprising a guide tube, a central tube provided on the lower side of the guide tube, a guide shoe connected to the lower part of the central tube by a positioning pin, a push sleeve connected to the outer circle of the guide tube by a setting pin, a one-way toothed hole machined in the inner hole of the push sleeve, and a one-way toothed ring machined on the upper part of the central tube. The one-way toothed hole and one-way toothed ring cooperate to allow the propulsion sleeve to move only downwards. A trigger tube is sleeved on the outside of the central tube and is pressed under the lower part of the propulsion sleeve. The trigger tube is sleeved in sequence with an upper cone, a slip, a lower cone, a rubber tube, and a spacer ring on the lower side of the propulsion sleeve. A blasting cleaning cylinder is provided between the spacer ring and the pilot shoe. The blasting cleaning cylinder is sleeved on the outside of the central tube and has an annular hollow cylinder structure. An annular piston is provided inside the blasting cleaning cylinder. The piston and the blasting cleaning cylinder are fitted with a sealing ring. The space below the piston of the blasting cleaning cylinder is filled with cleaning fluid, and the space above the piston is filled with explosive powder. A through hole is opened on the upper end face of the blasting cleaning cylinder. The ignition cap is connected to the through hole through a limiting shear pin. The ignition cap is installed with firing powder. A firing pin is provided at the lower end of the trigger tube at the ignition cap.

[0006] The blasting cleaning cylinder has flushing holes arranged vertically at the lower part of its outer circumference. The flushing holes are evenly distributed along the circumference of the outer circumference of the blasting cleaning cylinder. The outer side of the flushing holes is machined with stepped holes of reduced diameter, and glass plates are sealed and bonded to the inside of the stepped holes.

[0007] The outer surface of the rubber tube is covered with a cleaning cloth. The cleaning cloth is elastic and is fixedly connected to the lower cone and spacer ring on both the upper and lower sides. The cleaning cloth is taut during installation. A shearing ring is vulcanized and fixed in the middle of the outer circle of the rubber tube. The inner side of the shearing ring has evenly distributed support pillars that extend to the inner hole of the rubber tube. The rubber tube has a groove at the shearing ring. A shearing ring is installed in the groove. The shearing ring extends into the groove and presses the cleaning cloth onto the shearing ring. The inner side of the shearing ring has a pointed structure. The shearing rings are open-ring spirals stacked together.

[0008] There are three slips. The outer surface of the lower vertebra has three guide grooves evenly distributed around its circumference. The inner side of the slips extends into the guide grooves, and the outer sides of the three slips are fitted with elastic straps.

[0009] The propulsion sleeve extends downwards from the outside of the trigger tube by a propulsion tube, and there is a distance between the propulsion tube and the upper vertebral body.

[0010] The blasting cleaning cylinder and the piston are connected by blasting shear pins.

[0011] The guide tube, propulsion sleeve, trigger tube, upper cone, slip, lower cone, diaphragm ring, blasting cleaning cylinder, guide shoe, shearing ring, shearing ring and support are all made of soluble metal, and the rubber sleeve is made of soluble rubber.

[0012] The beneficial effects of this invention are as follows: By setting a blasting cleaning cylinder on the lower side of the rubber sleeve, the invention utilizes the action of the propulsion sleeve to trigger a blast. The blasting explosive uses high pressure and high shock wave to push the piston down at high speed, squeezing the cleaning fluid to shatter the glass fragments. The high-speed cleaning fluid washes the inner wall of the casing. Then, the rubber sleeve descends to the cleaned casing area. While expanding, the rubber sleeve wipes the cleaned area. Through the above-mentioned technical means, the setting force of the soluble bridge plug is improved, the pressure resistance of the soluble bridge plug is improved, and the smooth progress of fracturing operations is ensured. The broken glass fragments can also play a role in sandblasting and rust removal on the inner wall of the casing, further improving the smoothness of the inner wall of the casing. Attached Figure Description

[0013] Appendix Figure 1 This is a schematic diagram of the structure of the present invention;

[0014] Appendix Figure 2 It is attached Figure 1 Enlarged view of point A;

[0015] Appendix Figure 3 It is attached Figure 1 Enlarged view of point B;

[0016] Appendix Figure 4 It is attached Figure 1 Enlarged view of point C;

[0017] Appendix Figure 5 The structure of the blasting cleaning cylinder is shown in the schematic diagram.

[0018] Appendix Figure 6 It is attached Figure 5 Enlarged view of point D;

[0019] Appendix Figure 7 This is a schematic diagram of the shear ring structure;

[0020] Appendix Figure 8 This is a schematic diagram of the lower vertebral body.

[0021] In the diagram, 1-guide tube, 101-center tube, 102-one-way toothed ring, 2-propulsion sleeve, 201-one-way toothed hole, 202-propulsion tube, 3-upper cone, 4-slipper, 5-elastic band, 6-lower cone, 601-guide groove, 7-rubber sleeve, 701-groove, 8-spacer ring, 9-blasting cleaning cylinder, 901-flushing hole, 902-step hole, 903-glass plate, 904-through hole, 10-guide shoe, 11-trigger tube, 12-positioning pin, 13-setting pin, 14-limiting shear pin, 15-blasting shear pin, 16-piston, 17-firing pin, 18-ignition cap, 19-firing powder, 20-shear ring, 21-cleaning cloth, 22-shear ring, 23-support column, 24-blasting powder. Detailed Implementation

[0022] like Figures 1-8 As shown, a soluble bridge plug for fracturing includes a guide tube 1, a central tube 101 on the lower side of the guide tube 1, a guide shoe 10 connected to the lower part of the central tube 101 by a positioning pin 12, and an advance sleeve 2 connected to the outer circumference of the guide tube 1 by a setting pin 13 to prevent premature setting. The inner hole of the advance sleeve 2 is machined with a one-way toothed hole 201, and the upper part of the central tube 101 is machined with a one-way toothed ring 102. The one-way toothed hole 201 and the one-way toothed ring 102 cooperate to allow the advance sleeve 2 to move only downwards. A trigger tube 11 is sleeved on the outer side of the central tube 101, pressing against the lower part of the advance sleeve 2. An upper cone 3, a slip 4, a lower cone 6, a rubber sleeve 7, and a spacer ring 8 are sequentially sleeved on the lower side of the advance sleeve 2 on the trigger tube 11. A blasting cleaning cylinder 9 is provided between the spacer ring 8 and the guide shoe 10, sleeved on the outer side of the central tube 101. The blasting cleaning cylinder 9 has an annular hollow cylinder structure. The device is equipped with an annular piston 16, which is fitted with a sealing ring through a gap. The space below the piston 16 in the explosive cleaning cylinder 9 is filled with cleaning fluid, and the space above the piston 16 in the explosive cleaning cylinder 9 is filled with explosive powder 24. A through hole 904 is opened on the upper end face of the explosive cleaning cylinder 9. A ignition cap 18 is connected to the through hole 904 through a limiting shear pin 14. A firing powder 19 is installed in the ignition cap 18. A firing pin 17 is provided at the lower end of the trigger tube 11 at the ignition cap 18.

[0023] The blasting cleaning cylinder 9 has flushing holes 901 arranged vertically on the lower part of its outer circle. The flushing holes 901 are evenly distributed along the circumference of the outer circle of the blasting cleaning cylinder 9. A stepped hole 902 with a reduced diameter is machined on the outer side of the flushing hole 901. A glass sheet 903 is sealed and bonded to the inside of the stepped hole 902.

[0024] The outer surface of the rubber sleeve 7 is covered with a cleaning cloth 21. The cleaning cloth 21 is elastic and is fixedly connected to the lower cone 6 and the spacer ring 8 on both the upper and lower sides. The cleaning cloth 21 is taut during installation. A shearing ring 22 is vulcanized and fixed in the middle of the outer circle of the rubber sleeve 7. The inner side of the shearing ring 22 is provided with circumferentially distributed support pillars 23. The support pillars 23 extend to the inner hole of the rubber sleeve 7. The rubber sleeve 7 has a groove 701 at the shearing ring 22. A shearing ring 20 is installed in the groove 701. The shearing ring 20 extends into the groove 701 and presses the cleaning cloth 21 onto the shearing ring 22. The inner side of the shearing ring 20 has a pointed structure. The shearing ring 20 has an open-ring spiral stacked structure.

[0025] There are three slips 4. The outer surface of the lower vertebra 6 has three circumferentially distributed guide grooves 601. The inner side of the slips 4 extends into the guide grooves 601. The outer sides of the three slips 4 are covered with elastic straps 5.

[0026] The push sleeve 2 extends downwards from the outside of the trigger tube 11 by a push tube 202, and there is a distance between the push tube 202 and the upper vertebral body 3.

[0027] The blasting cleaning cylinder 9 and the piston 16 are connected by blasting shears 15. The function of the blasting shears 15 is that when the blasting gunpowder 24 explodes, a certain blasting pressure is formed above the piston 16, and the piston 16 will shear the blasting shears 15. The blasting gunpowder 24 pushes the piston 16 down at high speed with high pressure and high shock wave, squeezing the cleaning fluid to break the glass shard 903. The high-speed cleaning fluid washes the inner wall of the casing. The broken glass shard 903 can also play a role in sandblasting and rust removal of the inner wall of the casing, further improving the smoothness of the inner wall of the casing.

[0028] The soluble bridge plug's blasting cleaning cylinder 9 is lowered into the sleeve section requiring setting. The setting tool pulls the guide shoe 10, simultaneously pushing the pusher sleeve 2 downwards. As the pusher sleeve 2 descends, the firing pin 17 descends and strikes the ignition powder 19. The ignition powder 19 ignites the blasting powder 24, causing an explosion. The blasting powder 24, with its high pressure and high shock wave, pushes the piston 16 downwards at high speed, squeezing the cleaning fluid to shatter the glass plate 903. The high-speed cleaning fluid washes the inner wall of the sleeve. Then, the soluble bridge plug's rubber sleeve 7 is lowered to the cleaned sleeve section. The pusher sleeve 2 continues to descend, compressing the upper cone 3 and lower cone 6. The slip 4 expands outwards, and the rubber sleeve 7 is compressed and expands outwards. After the rubber sleeve 7 expands, the inner wall of the sleeve compresses the shear ring 20, causing it to contract. Together with the shear ring 22, they cut the cleaning cloth 21 in the middle. The elastic cleaning cloth 21 contracts to the upper and lower sides, thus cleaning the setting surface and ensuring the sealing effect of the setting section.

[0029] This invention utilizes a blasting cleaning cylinder 9 located below the casing 7. The blasting is triggered by the movement of the propulsion sleeve 2, and the explosive charge 24, with its high pressure and high shock wave, pushes the piston 16 downwards at high speed, squeezing the cleaning fluid to shatter the glass shard 903. The high-speed cleaning fluid then washes the inner wall of the casing. The casing 7 is then lowered to the cleaned casing section. As the casing 7 expands, it simultaneously wipes the cleaned area. These techniques improve the setting force and pressure resistance of the soluble bridge plug, ensuring the smooth operation of fracturing.

[0030] The guide tube 1, propulsion sleeve 2, trigger tube 11, upper cone 3, slip 4, lower cone 6, spacer ring 8, blasting cleaning cylinder 9, guide shoe 10, shear ring 20, shear ring 22 and support column 23 are all made of soluble metal, and the rubber sleeve 7 is made of soluble rubber.

Claims

1. A soluble bridge plug for fracturing, comprising a guide tube (1), characterized in that: The guide tube (1) has a central tube (101) on its lower side. The lower part of the central tube (101) is connected to the guide shoe (10) by a positioning pin (12). The outer circle of the guide tube (1) is connected to the push sleeve (2) by a sealing pin (13). The inner hole of the push sleeve (2) is machined with a one-way toothed hole (201). The upper part of the central tube (101) is machined with a one-way toothed ring (102). The one-way toothed hole (201) and the one-way toothed ring (102) cooperate to allow the propulsion sleeve (2) to move only downwards. A trigger tube (11) is sleeved on the outside of the central tube (101). The trigger tube (11) is pressed against the lower part of the propulsion sleeve (2). The trigger tube (11) is sleeved on the lower side of the propulsion sleeve (2) in sequence with an upper cone (3), a slip (4), a lower cone (6), a rubber sleeve (7), and a spacer (8). A blasting cleaning cylinder (9) is provided between the spacer (8) and the guide shoe (10). The blasting cleaning cylinder (9) is sleeved on the outside of the central tube (101). The blasting cleaning cylinder (9) has an annular hollow cylinder structure. 9) An annular piston (16) is provided inside. The piston (16) and the blasting cleaning cylinder (9) are fitted with a sealing ring. The space below the piston (16) of the blasting cleaning cylinder (9) is filled with cleaning fluid, and the space above the piston (16) of the blasting cleaning cylinder (9) is filled with explosive powder (24). A through hole (904) is opened on the upper end face of the blasting cleaning cylinder (9). The ignition cap (18) is connected to the through hole (904) through a limiting shear pin (14). The ignition cap (18) is filled with firing powder (19). The lower end of the trigger tube (11) is provided with a firing pin (17) at the ignition cap (18). The blasting cleaning cylinder (9) has flushing holes (901) arranged vertically on the lower part of its outer circle. The flushing holes (901) are evenly distributed along the circumference of the outer circle of the blasting cleaning cylinder (9). A stepped hole (902) with a reduced diameter is machined on the outside of the flushing hole (901). A glass plate (903) is sealed and bonded to the inside of the stepped hole (902) of the flushing hole (9).

2. The soluble bridge plug for fracturing according to claim 1, characterized in that: The outer surface of the rubber tube (7) is covered with a cleaning cloth (21). The cleaning cloth (21) is elastic. The upper and lower sides of the cleaning cloth (21) are fixedly connected to the lower cone (6) and the spacer (8). The cleaning cloth (21) is taut during installation. A shearing ring (22) is vulcanized and fixed in the middle of the outer circle of the rubber tube (7). The inner side of the shearing ring (22) is provided with a circumferentially distributed support column (23). The support column (23) extends to the inner hole of the rubber tube (7). The rubber tube (7) has a groove (701) at the shearing ring (22). A shearing ring (20) is installed in the groove (701). The shearing ring (20) extends into the groove (701) and presses the cleaning cloth (21) onto the shearing ring (22). The inner side of the shearing ring (20) is a pointed structure. The shearing ring (20) is an open-ring spiral stacked structure.

3. The soluble bridge plug for fracturing according to claim 1, characterized in that: There are three slips (4). The outer surface of the lower vertebra (6) has three guide grooves (601) evenly distributed around the circumference. The inner side of the slip (4) extends into the guide groove (601). The outer sides of the three slips (4) are covered with elastic straps (5).

4. The soluble bridge plug for fracturing according to claim 1, characterized in that: The push sleeve (2) extends downwards from the trigger tube (11) by a push tube (202), and there is a distance between the push tube (202) and the upper vertebral body (3).

5. A soluble bridge plug for fracturing according to claim 1, characterized in that: The blasting cleaning cylinder (9) and the piston (16) are connected by blasting shears (15).

6. A soluble bridge plug for fracturing according to claim 1 or 2, characterized in that: The guide tube (1), propulsion sleeve (2), trigger tube (11), upper cone (3), slip (4), lower cone (6), diaphragm (8), blasting cleaning cylinder (9), guide shoe (10), shear ring (20), shear (ring 22) and support (23) are all made of soluble metal, and the rubber tube (7) is made of soluble rubber.

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