Automatic recovery type blanking plug and method

Abstract

The invention belongs to the technical field of oil production engineering in the petroleum industry, and particularly relates to an automatic recovery type blanking plug and a method thereof.The automatic recovery type blanking plug comprises a clamping base and a base, and a first clamping groove is formed in the upper portion of the clamping base; the soluble screwed plug is connected with the lower part of the base; the clamping block is movably arranged in the first clamping groove and connected to the oil pipe preset working barrel in a clamped mode. The spring is used for applying inward bias force to the clamping block; the lower portion of the piston rod is connected with the base, the piston rod is fixedly connected with the clamping base through a fixing part, a third clamping groove is formed in the upper portion of the piston rod, a throttling hole is formed in the piston rod, and reservoir liquid flows into the throttling hole to generate throttling pressure difference and then is pushed to move upwards to cut off the fixing part, so that the clamping block is extruded into the third clamping groove. And the blanking plug is automatically separated from the preset working barrel. A throttling pressure cavity is formed by the soluble screwed plug and the piston rod, meanwhile, the plug is pushed to move upwards through thrust generated by well pressure fluid moving upwards, and the purpose of automatic recycling is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production engineering in the petroleum industry, and in particular relates to an automatic recovery plugging device and a method. Background Art

[0002] In the process of stabilizing production and improving efficiency and comprehensive management of old oil fields, due to the influence of geological conditions and reservoir properties, some oil and water wells have high water injection pressure, long pressure relief cycle during inspection, and long energy replenishment process after water injection restoration; or use well killing hydraulic wells for operation; oil wells have slow production recovery after operation due to the influence of well washing fluid or well killing fluid; for oil fields with water-sensitive and salt-sensitive reservoirs, the reservoirs are easily contaminated by well killing fluid and the production drops seriously after operation. Therefore, it is necessary to carry out pressure operation during oil and water well operation, and plugs are usually used to block the pressure of the lower reservoir during pressure on-site construction.

[0003] The plugs currently used are usually non-recoverable plugs or instrument-inserted plugs, which have long operation cycles, high costs and high salvage risks.

[0004] For example, the patent document with Chinese patent application number CN110043214A discloses an oil pipe plug, which belongs to the field of oil well pressure operation tools. The oil pipe plug includes a pipe body with oil holes at both ends, and a one-way plug is provided in the channel between the two oil holes. When the well-clearing operation is required to reach the designed position or the operator performs well washing operation at the bottom of the well, after going down to the predetermined position, the oil pipe is pressurized by the pump of the cement truck on the ground, and the pressure acts on the head. When the pressure reaches 7-8 MPa, the screw connected to the one-way plug is disconnected by shearing the screw, and the plug falls, forming a forward and reverse washing circulation channel, and the well can be washed normally. At this time, there is active water in the wellbore, and no blowout will occur during the drilling operation, which can ensure that there will be no well gust or blowout in the well-clearing operation process, and can achieve rapid control of well gust or blowout.

[0005] For example, the patent document with Chinese patent application number CN1113982527A discloses a small-diameter oil pipe plug, which includes a starting locking mechanism, which includes a positioning pressure cap, the positioning pressure cap is penetrated by a core shaft, the core shaft does not completely escape from the positioning pressure cap, and the head end of the positioning pressure cap is detachably connected with an elastic locking piece: the air pressure storage power mechanism includes a power push cylinder arranged at the head end of the elastic locking piece, and the core shaft is fixed with a piston push head: the positioning mechanism includes a wing plate assembly arranged at the head end of the power push cylinder, the wing plate assembly is used to position the small-diameter oil pipe plug at the oil pipe coupling, the head end of the wing plate assembly is provided with a retaining spring assembly, the retaining spring assembly is used to make the core shaft slide in one direction, and the head end of the retaining spring assembly is provided with a plurality of hinge slips arranged along the circumferential direction; the sealing mechanism includes an elastic sealing piece, and extrusion pieces are arranged at both ends of the elastic sealing piece, and the core shaft passes through two extrusion pieces and the elastic sealing piece. The outer diameter of the device is not more than 38 mm, which can meet the current construction requirements, and has a large sealing force, strong pressure resistance, and a high sealing success rate.

[0006] For example, the patent document with Chinese patent application number CN114439415A discloses a double-barrier oil pipe plugging device and method for pressure completion operation. The device and method belong to the technical field of special tools for oil wells. By setting a fixing ring in the inner cavity of the body, both the first rupture disk and the check valve can be fixed. The check valve can only allow the fluid to pass from the first rupture disk to the first rupture disk. When the pressure on the upper side of the first rupture disk increases, the fluid can flow through the through hole and the check valve to between the first rupture disk and the second rupture disk, so that a large pressure difference will not be formed on both sides of the first rupture disk to avoid rupture, thereby ensuring that the first rupture disk and the second rupture disk are both within the safe working range, ensuring that the device can play a double insurance role and meet the requirements of high-pressure gas well pressure operation. The technical solution can also rupture the first rupture disk and the second rupture disk by simply pressing the oil pipe, so as to achieve the purpose of unblocking, simplify the operation process, shorten the operation time, and save the operation cost.

[0007] However, the plugs mentioned in the above technical solutions have the problems of being non-recoverable or requiring instruments to be lowered for recovery, long operation cycle, high cost and high salvage risk.

[0008] Based on this, the existing technology still needs to be improved. Summary of the invention

[0009] The purpose of the present invention is to address the deficiencies of the prior art and provide an automatically recoverable plug and method. After the tubing is lowered below the surface sleeve, a throttling pressure chamber is formed by a dissolvable wire plug and a piston rod, and the thrust generated by the upward well pressure fluid is used to push the plug upward, thereby achieving the purpose of automatic recovery.

[0010] According to one aspect of the present invention, there is provided an automatic retractable plug, which comprises: a holder and a base, the holder and the base are fixedly connected, the holder is arranged at the upper part of the base, and a first slot is arranged at the upper part of the holder; a soluble thread plug, the soluble thread plug is fixedly connected to the lower part of the base and is used to block the base; a block, the block is movably arranged in the first slot and is connected to the oil pipe pre-set working cylinder through the first slot, and a spring slot is arranged on the outer side of the block; a spring, the spring is arranged in the spring slot and applies an inward biasing force to the block; and a piston rod, the lower part of the piston rod is movably connected to the base, the piston rod is fixedly connected to the holder through a fixing component, the upper part of the piston rod is provided with a third slot, and a throttling hole is arranged inside the piston rod, and when the throttling pressure difference generated by the reservoir liquid flowing into the throttling hole reaches a preset value, the piston rod is pushed upward to cut off the fixing component, so that the block is squeezed into the third slot, so that the automatic retractable plug is automatically separated from the pre-set working cylinder.

[0011] In an embodiment of the present invention, the clamping block is used to clamp into a second clamping groove on the preset working cylinder of the oil pipe, so as to fix the automatic retractable plugging device in the preset working cylinder.

[0012] In an embodiment of the present invention, a limit block is provided at the lower portion of the clamping seat, and the limit block is used to limit the piston rod at a preset stroke position when the piston rod moves upward.

[0013] In an embodiment of the present invention, the blocking block overlaps with the third blocking groove when the piston rod moves upward to the preset stroke position, and enters the third blocking groove under the push of the spring to separate the automatic retractable plugger from the preset working cylinder.

[0014] In an embodiment of the present invention, an O-ring is provided on the base, and the lower portion of the piston rod is movably connected to the base via the O-ring.

[0015] In an embodiment of the present invention, the fixing component is a shear nail, a shear nail hole is correspondingly provided on the upper part of the base, a shear nail groove is provided on the upper part of the piston rod, the shear nail passes through the shear nail hole and is inserted into the shear nail groove to fix the piston rod.

[0016] In an embodiment of the present invention, the connection between the holder and the base is a threaded connection, and the connection between the soluble thread plug and the base is a threaded connection.

[0017] In an embodiment of the present invention, the size of the soluble wire plug is set according to a preset dissolution time and material.

[0018] In an embodiment of the present invention, the soluble wire plug is made of polylactic acid and / or epoxy resin.

[0019] In an embodiment of the present invention, a plurality of chamfered expansion pieces movably connected to the guide housing and the suspended expansion cone are arranged along the circumference.

[0020] According to another aspect of the present invention, there is provided a method for automatic recovery of a plug, which comprises the following steps performed based on the automatic recovery plug described in any one of the above technical solutions: S1, placing the automatic recovery plug having a soluble thread plug of a preset size into the well, waiting until the soluble thread plug automatically dissolves and the reservoir liquid flows into the throttling hole of the piston rod; S2, after the throttling pressure difference reaches a preset value, pushing the piston rod upward and squeezing the block into the third slot, forcing the automatic recovery plug to separate from the preset working cylinder; S3, opening the wellhead oil pipe channel to drain the flow, so that the automatic recovery plug returns to the wellhead under the upward thrust of the upper and lower working pressure differences in the oil pipe, thereby realizing automatic recovery.

[0021] After the soluble wire plug of the present invention automatically dissolves, the throttling pressure difference between the upper and lower parts of the piston rod and the well pressure in the oil pipe are used to realize the periodic automatic recovery function, which effectively reduces the operation cycle, the cost of pressure operation and the risk of salvaging the plug, and provides technical support for the safe operation of the oil field. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic cross-sectional view of an automatic retractable plugging device according to an embodiment of the present invention is shown;

[0023] Figure 2 A structural diagram of an automatic retractable plugging device according to an embodiment of the present invention is shown; and

[0024] Figure 3 A schematic flow chart of an automatic plug recovery method according to an embodiment of the present invention is shown.

[0025] Description of reference numerals:

[0026] 1- holder; 2- shear pin; 3- block; 4- spring; 5- base; 6- piston rod; 7- soluble thread plug. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0028] In the description of the present invention, it should be understood that the terms: "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0029] According to one aspect of the present invention, there is provided an automatic retractable plugging device, such as Figure 1 and 2 As shown, it includes: a holder 1 and a base 5, the holder 1 and the base 5 are fixedly connected, the holder 1 is arranged at the upper part of the base 5, and the upper part of the holder 1 is provided with a first slot; a soluble thread plug 7, the soluble thread plug 7 is fixedly connected to the lower part of the base 5 and is used to block the base 5; a block 3, the block 3 is movably arranged in the first slot and passes through the first slot to be clamped to the preset working cylinder of the oil pipe, and a spring slot is arranged on the outer side of the block 3; a spring 4, the spring 4 is arranged in the spring slot and applies an inward biasing force to the block 3; and a piston rod 6, the lower part of the piston rod 6 is movably connected to the base 5, the piston rod 6 is fixedly connected to the holder 1 through a fixing component, the upper part of the piston rod 6 is provided with a third slot, and a throttling hole is arranged inside the piston rod 6. When the throttling pressure difference generated by the reservoir liquid flowing into the throttling hole reaches a preset value, the piston rod 6 is pushed upward to shear off the fixed component, so that the block 3 is squeezed into the third slot, and the plug is automatically separated from the preset working cylinder.

[0030] In an embodiment of the present invention, a second slot is provided on the tubing pre-set working cylinder, and the clamping block 3 is used to clamp into the second slot on the tubing pre-set working cylinder to fix the automatic retrievable plug in the preset working cylinder, and after clamping, it is lowered into the well together with the tubing string.

[0031] In an embodiment of the present invention, a limit block is provided at the lower portion of the holder 1, and the limit block is used to limit the piston rod 6 at a preset stroke position when the piston rod 6 moves upward, so as to prevent the piston rod 6 from exceeding the preset stroke range during the upward process and causing the device to malfunction.

[0032] In an embodiment of the present invention, after the soluble wire plug 7 is dissolved, the piston rod 6 moves upward under the push of the upper and lower throttling pressure difference to shear the shear nail 2, and the blocking block 3 coincides with the third blocking groove when the piston rod 6 moves upward to the preset stroke position, and enters the third blocking groove under the push of the spring 4, so that the automatic recovery plug is separated from the preset working cylinder.

[0033] In the embodiment of the present invention, an O-ring is provided on the base 5, the upper outer side of the base 5 is sealedly connected to the preset working cylinder through the O-ring, and the lower outer side of the piston rod 6 is movably connected to the base 5 through the O-ring. In order to ensure the durability of the device, the material of the O-ring is insoluble.

[0034] In the embodiment of the present invention, the fixing component is a shear nail 2, a shear nail hole is correspondingly provided on the upper part of the holder 1, a shear nail groove is provided on the upper part of the piston rod 6, and the shear nail 2 passes through the shear nail hole and is inserted into the shear nail groove to fix the piston rod 6. When the throttling pressure difference generated by the reservoir liquid flowing into the throttling hole reaches a preset value, the piston rod 6 is pushed upward to shear the shear nail 2, so that the block 3 is squeezed into the third groove, so that the plugging device is automatically separated from the preset working cylinder.

[0035] In the embodiment of the present invention, the connection between the card holder 1 and the base 5 is threaded connection, and the connection between the soluble thread plug 7 and the base 5 is threaded connection. The threaded connection has the advantages of being able to withstand high pressure and having good sealing performance, and is cheap and easy to obtain, and can facilitate the installation and removal of various components.

[0036] In the embodiment of the present invention, the size of the soluble plug 7 is set according to the preset dissolution time and material. The soluble plug 7 will automatically dissolve after a certain time in the well. In order to ensure that the dissolution time meets expectations, the size of the soluble plug 7 is set according to the preset dissolution time and material.

[0037] In the embodiment of the present invention, the material of the soluble wire plug 7 is polylactic acid and / or epoxy resin. Polylactic acid and epoxy resin are biodegradable materials, cheap and easily available and widely used in various fields, and are suitable as raw materials for the soluble wire plug 7.

[0038] According to another aspect of the present invention, a method for automatically recovering a plug is provided. Figure 1 and 2 As shown, it includes the following steps of performing the automatic retractable plugging device according to any one of the above technical solutions:

[0039] S1, placing the automatically recoverable plugging device with a soluble plug 7 of preset size into the well, and waiting until the soluble plug 7 automatically dissolves and the reservoir liquid flows into the throttling hole of the piston rod 6;

[0040] S2, after the throttling pressure difference reaches the preset value, the piston rod 6 is pushed upward and the block 3 is squeezed into the third slot, forcing the automatic recovery plug to separate from the preset working cylinder;

[0041] S3. Open the wellhead oil pipe channel to drain the flow, so that the plug returns to the wellhead under the upward thrust of the upper and lower working pressure differences in the oil pipe, realizing automatic recovery.

[0042] The present invention is further described below by specific examples:

[0043] During the on-site construction process, the automatic recoverable plug will be fixed in the preset working cylinder and lowered into the well together with the oil pipe string to block the oil pipe, thereby sealing the pressure in the oil pipe during operation. When the pressurized operation is completed and the soluble wire plug 7 is dissolved, the piston rod 6 moves upward to shear the shear nail 2 under the push of the internal upper and lower throttling pressure difference. The piston rod 6 continues to move upward to the limit block of the holder 1. At this time, the biasing force of the spring 4 presses the block 3 into the third groove on the upper part of the piston rod 6, separating the plug from the preset working cylinder. At this time, the wellhead pressure is observed to increase, and the wellhead oil pipe channel is opened to use the upward thrust of the upper and lower working pressure difference in the oil pipe to return to the wellhead so that the plug is automatically recovered, completing the entire pressurized operation process.

[0044] The embodiment of the present invention provides an automatic recoverable plug and method. The automatic recoverable plug has a reasonable structural design and innovative principle. After the soluble wire plug is automatically dissolved, the throttling pressure difference between the upper and lower parts of the piston rod and the well pressure in the oil pipe are used to realize the periodic automatic recovery function, which effectively reduces the operation cycle, the cost of pressure operation and the risk of salvaging the plug.

[0045] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. An automatic retractable plugging device, characterized in that: include: A card holder and a base, wherein the card holder and the base are fixedly connected, the card holder is arranged on the upper part of the base, and a first card slot is arranged on the upper part of the card holder; A soluble thread plug, which is fixedly connected to the lower part of the base and is used to seal the base; A clamping block, the clamping block is movably arranged in the first clamping slot and passes through the first clamping slot to be clamped to the oil pipe presetting working cylinder, and a spring groove is arranged on the outer side of the clamping block; a spring disposed in the spring slot and applying an inward biasing force to the block; and A piston rod, wherein the lower portion of the piston rod is movably connected to the base, the piston rod is fixedly connected to the holder via a fixing component, a third slot is provided at the upper portion of the piston rod, a throttling hole is provided inside the piston rod, and when the throttling pressure difference generated by the reservoir liquid flowing into the throttling hole reaches a preset value, the piston rod is pushed upward to shear off the fixing component, so that the block is squeezed into the third slot, and the automatic recovery plug is automatically separated from the preset working cylinder.

2. The automatic retractable plugging device according to claim 1, characterized in that: The clamping block is used to clamp into the second clamping groove on the preset working cylinder of the oil pipe so as to fix the automatic recovery plugger in the preset working cylinder.

3. The automatic retractable plugging device according to claim 1, characterized in that: A limit block is arranged at the lower part of the clamping seat, and the limit block is used to limit the piston rod at a preset stroke position when the piston rod moves upward.

4. The automatic retractable plugging device according to claim 3, characterized in that: The clamping block overlaps with the third clamping groove when the piston rod moves upward to the preset stroke position, and enters the third clamping groove under the push of the spring, so that the automatic recovery plugging device is separated from the preset working cylinder.

5. The automatic retractable plugging device according to claim 1, characterized in that: An O-type sealing ring is arranged on the base, and the lower part of the piston rod is movably connected to the base through the O-type sealing ring.

6. The automatic retractable plugging device according to claim 1, characterized in that: The fixing component is a shear nail, a shear nail hole is correspondingly arranged on the upper part of the clamping seat, a shear nail groove is arranged on the upper part of the piston rod, and the shear nail passes through the shear nail hole and is inserted into the shear nail groove to fix the piston rod.

7. The automatic retractable plugging device according to claim 1, characterized in that: The connection mode of the holder and the base is threaded connection, and the connection mode of the soluble thread plug and the base is threaded connection.

8. The automatic retractable plugging device according to claim 1, characterized in that: The size of the soluble wire plug is set according to the preset dissolution time and material.

9. The automatic retractable plugging device according to claim 8, characterized in that: The material of the soluble wire plug is polylactic acid and / or epoxy resin.

10. A method for automatically recovering a plug, characterized in that: The method comprises performing the following steps based on the automatic retractable plug according to any one of claims 1 to 9: S1, placing the automatically recoverable plugging device with a soluble plug of preset size into the well, and waiting until the soluble plug is automatically dissolved and the reservoir liquid flows into the throttling hole of the piston rod; S2, after the throttling pressure difference reaches the preset value, the piston rod is pushed upward and the card block is squeezed into the third card slot, forcing the automatic recovery plug to separate from the preset working cylinder; S3, opening the wellhead oil pipe channel to release the flow, so that the automatic recovery plug returns to the wellhead under the upward thrust of the upper and lower working pressure differences in the oil pipe, thereby realizing automatic recovery.

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