An automatic retrieval type plug and method

Abstract

The application belongs to the technical field of oil production engineering in the petroleum industry, and particularly relates to an automatic recovery type plug and method, wherein the automatic recovery type plug comprises a clamping seat and a base, the upper portion of the clamping seat is provided with a first clamping groove, a soluble plug is connected with the lower portion of the base, a clamping block is movably arranged in the first clamping groove and is clamped to a tubing preset working barrel, a spring applies an inward biasing force to the clamping block, and a piston rod is connected with the base at the lower portion, is fixedly connected with the clamping seat through a fixing part, is provided with a third clamping groove at the upper portion, is provided with a throttling hole inside, and is pushed to go up and cut off the fixing part after the throttling pressure difference is generated by the reservoir liquid flowing into the throttling hole, so that the clamping block is squeezed into the third clamping groove, and the plug is automatically separated from the preset working barrel. The soluble plug and the piston rod are used to form a throttling pressure cavity, and the plug is pushed to go up by the thrust generated by the well pressure fluid going up, so that the automatic recovery purpose is achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil production engineering in the petroleum industry, and particularly relates to an automatic recovery type plug and method. BACKGROUND

[0002] In the process of stable production and efficiency improvement and comprehensive management in old oilfields, due to the influence of factors such as geological conditions and reservoir properties, the injection pressure of part of the oil-water wells is high, the pressure relief period is long when checking the pipe, and the energy recovery process is long after resuming injection; or the well is pressurized after using well killing fluid for operation; the production recovery of the oil well is slow after operation due to the influence of the washing fluid or well killing fluid; for the oilfield with water-sensitive and salt-sensitive reservoirs, the reservoir is easily polluted by well killing fluid, and the production decreases seriously after operation. Therefore, it is necessary to carry out operation under pressure during the operation process of the oil-water well, and a plug is usually used to block the pressure of the lower reservoir during the operation process under pressure.

[0003] The currently used plugs are usually non-recoverable plugs or downhole instrument throwing plugs, which have long operation period, high cost and high fishing risk.

[0004] For example, the patent document with Chinese patent application number CN110043214A discloses a tubing plug, which belongs to the field of oil well downhole operation tools. The tubing plug of the well includes a pipe body provided with oil passing cavities at both ends, and a one-way plug is arranged in the passage between the two oil passing cavities. During the operation, the well is passed to the designed position or the operator performs the washing operation at the bottom of the well, and after being lowered to the predetermined position, the oil pipe is pressurized by the pump of the cement truck on the ground, the pressure acts on the head, when the pressure reaches 7-8 MPa, the screw rod connected with the one-way plug is disconnected by cutting the screw rod, the plug falls down, forming a positive and negative washing circulation channel, and the well can be normally washed. At this time, the wellbore is active water, and blowout will not occur during the drilling operation, which can ensure that the well flow or blowout will not occur during the well operation process, and the well flow or blowout can be quickly controlled.

[0005] For example, the patent document with the patent application number CN1113982527A discloses a small-diameter tubing plug, which comprises a starting locking mechanism, the starting locking mechanism comprises a positioning pressure cap, a mandrel is provided in the positioning pressure cap, the mandrel is not completely out of the positioning pressure cap, and the head end of the positioning pressure cap is detachably connected with an elastic locking piece; the gas pressure energy storage power mechanism comprises a power pushing barrel arranged at the head end of the elastic locking piece, and the mandrel is fixed with a piston push head; the positioning mechanism comprises a wing plate assembly arranged at the head end of the power pushing barrel, the wing plate assembly is used for positioning the small-diameter tubing plug at the tubing coupling, the head end of the wing plate assembly is provided with a snap spring assembly, the snap spring assembly is used for allowing the mandrel to slide in one direction, and the head end of the snap spring assembly is provided with a plurality of hinge slips arranged in the circumferential direction; and the sealing mechanism comprises an elastic sealing piece, the elastic sealing piece is provided with extrusion pieces at both ends, and the mandrel penetrates through the two extrusion pieces and the elastic sealing piece. The outer diameter of the device is not greater than 38mm, which can meet the current construction requirements, has large plugging force, high pressure resistance, and high plugging success rate.

[0006] For example, the patent document with the patent application number CN114439415A discloses a double-barrier tubing plug device and method for well completion under pressure, which belongs to the technical field of special tools for oil wells. The device comprises a fixed ring arranged in the inner cavity of the body, which can fix the first rupture disc and the check valve. The check valve only allows fluid to pass from the first rupture disc to the direction of the first rupture disc, so that when the pressure on the upper side of the first rupture disc increases, the fluid can flow through the through hole and the check valve to the space between the first rupture disc and the second rupture disc, preventing a large pressure difference from being formed on both sides of the first rupture disc and avoiding rupture, so that the first rupture disc and the second rupture disc can work within a safe range, ensuring that the device can play a double insurance role and meet the requirements of high-pressure gas well completion under pressure. The technical scheme can also achieve the purpose of unblocking by simply pressing the oil pipe, simplifying the operation process, shortening the operation time, and saving the operation cost.

[0007] However, the plug mentioned in the above technical scheme has the problems of non-recyclability or recovery by lowering the instrument, long operation cycle, high cost, and high risk of fishing.

[0008] Therefore, the prior art still needs to be improved. SUMMARY

[0009] The purpose of the present application is to overcome the shortcomings of the prior art and provide an automatic recovery type plug and method. After the pipe string is lowered below the surface sleeve, a throttling pressure chamber is formed between the dissolvable plug and the piston rod, and the upward thrust generated by the well pressure fluid is used to push the plug upward, achieving the purpose of automatic recovery.

[0010] According to an aspect of the present application, there is provided an automatic recovery type plug, comprising: a seat and a base, which are fixedly connected, the seat being arranged on the upper portion of the base, the upper portion of the seat being provided with a first clamping groove; a soluble plug, which is fixedly connected with the lower portion of the base and used for plugging the base; a clamping block, which is movably arranged in the first clamping groove and clamped to a tubing preset working barrel through the first clamping groove, the outer side of the clamping block being provided with a spring groove; a spring, which is arranged in the spring groove and applies an inward biasing force to the clamping block; and a piston rod, the lower portion of which is movably connected with the base, the piston rod being fixedly connected with the seat through a fixing component, the upper portion of the piston rod being provided with a third clamping groove, the inside of the piston rod being provided with a throttling hole, the piston rod being pushed to ascend and cut off the fixing component when the throttling pressure difference generated by the reservoir fluid flowing into the throttling hole reaches a preset value, so that the clamping block is pressed into the third clamping groove, and the automatic recovery type plug is automatically separated from the preset working barrel.

[0011] In an embodiment of the present application, the clamping block is used for clamping to a second clamping groove on the tubing preset working barrel, so as to fix the automatic recovery type plug in the preset working barrel.

[0012] In an embodiment of the present application, the lower portion of the seat is provided with a limiting block, which is used for limiting the piston rod at a preset stroke position when the piston rod ascends.

[0013] In an embodiment of the present application, the clamping block coincides with the third clamping groove when the piston rod ascends to the preset stroke position, and enters the third clamping groove under the pushing of the spring, so as to separate the automatic recovery type plug from the preset working barrel.

[0014] In an embodiment of the present application, the base is provided with an O-shaped sealing ring, and the lower portion of the piston rod is movably connected with the base through the O-shaped sealing ring.

[0015] In an embodiment of the present application, the fixing component is a shear pin, the upper portion of the seat is correspondingly provided with a shear pin hole, the upper portion of the piston rod is provided with a shear pin groove, the shear pin passes through the shear pin hole and is inserted into the shear pin groove, and the shear pin is used for fixing the piston rod.

[0016] In an embodiment of the present application, the seat and the base are connected in a thread connection mode, and the soluble plug and the base are connected in a thread connection mode.

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

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

[0019] In the embodiment of the present application, the plurality of chamfered expanding blades movably connected with the guide shell and the hanging expanding cone are arranged circumferentially.

[0020] According to another aspect of the present application, there is provided a plug automatic recovery method, which comprises the following steps performed by the automatic recovery plug according to any one of the above technical solutions: S1, placing the automatic recovery plug with a soluble plug of a preset size into a well, waiting until the soluble plug is automatically dissolved, and then allowing reservoir fluid to flow into the throttle hole of the piston rod; S2, after the throttle pressure difference reaches a preset value, pushing the piston rod to move upward and extruding the clamping block into the third clamping groove, so as to force the automatic recovery plug to separate from the preset working barrel; S3, opening the wellhead tubing channel to discharge, so that the automatic recovery plug returns to the wellhead under the upward thrust of the tubing working pressure difference, thereby realizing automatic recovery.

[0021] The automatic recovery function of the soluble plug is realized by using the upward and downward throttle pressure difference of the piston rod and the well pressure in the tubing, which effectively reduces the operation cycle, the cost of pressure operation and the fishing risk of the plug, and provides technical support for the safe operation of the oilfield. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A cross-sectional schematic view of an automatic recovery plug according to an embodiment of the present application is shown;

[0023] Figure 2 A structural view of an automatic recovery plug according to an embodiment of the present application is shown; and

[0024] Figure 3 A flowchart of a plug automatic recovery method according to an embodiment of the present application is shown.

[0025] BRIEF DESCRIPTION OF DRAWINGS

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

[0027] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application are further described in detail below with reference to the drawings.

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0029] According to one aspect of the present application, an automatic recovery type plug is provided, as shown in Figure 1 and 2 It comprises a card seat 1 and a base 5, the card seat 1 and the base 5 are fixedly connected, the card seat 1 is arranged on the upper part of the base 5, and the upper part of the card seat 1 is provided with a first clamping groove; a soluble plug 7 is fixedly connected with the lower part of the base 5 and used for plugging the base 5; a clamping block 3 is movably arranged in the first clamping groove and clamped to the tubing preset working barrel through the first clamping groove, and the outer side of the clamping block 3 is provided with a spring groove; a spring 4 is arranged in the spring groove and applies an inward biasing force to the clamping block 3; and a piston rod 6 is movably connected with the base 5 at the lower part, the piston rod 6 is fixedly connected with the card seat 1 through a fixing part, the upper part of the piston rod 6 is provided with a third clamping groove, and the inside of the piston rod 6 is provided with a throttling hole; when the throttling pressure difference generated by the reservoir fluid flowing into the throttling hole reaches a preset value, the piston rod 6 is pushed to go up and cut off the fixing part, so that the clamping block 3 is extruded into the third clamping groove, and the plug is automatically separated from the preset working barrel.

[0030] In the embodiment of the present application, the tubing preset working barrel is provided with a second clamping groove, the clamping block 3 is used for clamping to the second clamping groove on the tubing preset working barrel, so as to fix the automatic recovery type plug in the preset working barrel, and after the clamping is completed, the tubing string is lowered into the well together.

[0031] In the embodiment of the present application, the lower part of the card seat 1 is provided with a limiting block, the limiting block is used for limiting the piston rod 6 at a preset stroke position when the piston rod 6 goes up, so as to prevent the piston rod 6 from exceeding the preset stroke range in the upstroke process and causing the device to malfunction.

[0032] In the embodiment of the present application, after the soluble plug 7 is dissolved, the piston rod 6 is pushed to go up and cut off the shear pin 2 under the up-down throttling pressure difference, the clamping block 3 coincides with the third clamping groove when the piston rod 6 goes up to the preset stroke position, and the clamping block 3 enters the third clamping groove under the pushing of the spring 4, so as to separate the automatic recovery type plug from the preset working barrel.

[0033] In the embodiment of the present invention, an O-ring is provided on the base 5. The upper outer portion of the base 5 is sealedly connected to the pre-set working cylinder via the O-ring, and the lower outer portion of the piston rod 6 is movably connected to the base 5 via the O-ring. To ensure the durability of the device, the O-ring is made of an insoluble material.

[0034] In this embodiment of the present invention, the fixing component is a shear pin 2. A corresponding shear pin hole is provided on the upper portion of the retaining base 1, and a shear pin groove is provided on the upper portion of the piston rod 6. The shear pin 2 passes through the shear pin hole and is inserted into the shear pin groove to secure the piston rod 6. When the throttling pressure differential generated by the reservoir fluid flowing into the throttling hole reaches a preset value, the piston rod 6 is pushed upward to shear the shear pin 2, forcing the retaining block 3 into the third retaining groove, automatically separating the plug from the pre-set working cylinder.

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

[0036] In an embodiment of the present invention, the size of the soluble plug 7 is set according to a preset dissolution time and material. The soluble plug 7 will automatically dissolve after a certain period of time underground. In order to ensure that the dissolution time meets the expected time, 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 readily 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. Place the automatically retrievable plug with a soluble plug 7 of preset size into the well, and wait until the soluble plug 7 automatically dissolves and the reservoir fluid flows into the throttle 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 card block 3 is squeezed into the third card slot, forcing the automatic recovery plug to separate from the preset working cylinder;

[0041] S3. Open the wellhead oil pipe channel to drain the fluid, 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 means of specific examples:

[0043] The automatic recovery type plug is fixed in the preset working barrel during the field construction process, and is lowered into the well together with the tubing string, plugs the tubing, and plays the role of plugging the tubing internal pressure during operation, when the pressure operation is completed and the soluble plug 7 is dissolved, the piston rod 6 is pushed up by the internal up and down throttling pressure difference to cut the shear pin 2, the piston rod 6 continues to go up to the limiting block of the clamping seat 1, at this time the biasing force of the spring 4 will press the clamping block 3 into the third clamping groove on the upper part of the piston rod 6, so that the plug is separated from the preset working barrel, at this time the wellhead pressure is observed to be increased, the wellhead tubing channel is opened to use the uplink thrust of the up and down working pressure difference in the tubing to return to the wellhead to make the plug automatically recover, and the whole pressure operation process is completed.

[0044] The automatic recovery type plug and method provided by the embodiment of the application have reasonable structure design and innovative principle, after the soluble plug is automatically dissolved, the periodic automatic recovery function is realized by using the up and down throttling pressure difference of the piston rod and the well pressure in the tubing, and the operation cycle, the pressure operation cost and the fishing risk of the plug are effectively reduced.

[0045] Those skilled in the art should understand that the above discussion of any embodiment is only exemplary, and is not intended to imply that the scope (including claims) of the embodiments of the application is limited to these examples; under the idea of the embodiments of the application, the above embodiments or technical features in different embodiments can also be combined, and there are many other changes of different aspects of the embodiments of the application as above. In order to be brief, they are not provided in details. Therefore, any omission, modification, equivalent replacement, improvement, etc. made in the spirit and principle of the embodiments of the application should be included in the protection scope of the embodiments of the application.

Claims

1. An automatic-recovery-type plug, characterized by comprising: The application relates to an automatic recovery type plug. The application comprises a card seat and a base, the card seat and the base are fixedly connected, the card seat is arranged on the upper part of the base, and the upper part of the card seat is provided with a first clamping groove; A soluble plug is fixedly connected with the lower part of the base and used for plugging the base; A clamping block is movably arranged in the first clamping groove and clamped to a tubing preset working barrel through the first clamping groove, and the outer side of the clamping block is provided with a spring groove; A spring is arranged in the spring groove and applies an inward biasing force to the clamping block; and A piston rod is movably connected with the base at the lower part of the piston rod, the piston rod is fixedly connected with the card seat through a fixing component, the upper part of the piston rod is provided with a third clamping groove, the inside of the piston rod is provided with a throttling hole, and the piston rod is pushed to go up and cut off the fixing component when the throttling pressure difference generated by the reservoir liquid flowing into the throttling hole reaches a preset value, so that the clamping block is extruded into the third clamping groove, and the automatic recovery type plug is automatically separated from the preset working barrel.

2. The automatic-recovery-type plug according to claim 1, characterized by The clamping block is used for clamping the second clamping groove on the tubing preset working barrel, so that the automatic recovery type plug is fixed in the preset working barrel.

3. The automatic-recovery-type plug according to claim 1, characterized by The lower part of the card seat is provided with a limiting block, the limiting block is used for limiting the piston rod at a preset stroke position when the piston rod goes up.

4. The automatic-recovery-type plug according to claim 3, characterized by The clamping block coincides with the third clamping groove when the piston rod goes up to the preset stroke position, and the clamping block enters the third clamping groove under the pushing of the spring, so that the automatic recovery type plug is separated from the preset working barrel.

5. The automatic-retrieving plug of claim 1, wherein An O-shaped sealing ring is arranged on the base, and the lower part of the piston rod is movably connected with the base through the O-shaped sealing ring.

6. The automatic-retrieving plug of claim 1, wherein The fixing component is a shear pin, the upper part of the card seat is correspondingly provided with a shear pin hole, the upper part of the piston rod is provided with a shear pin groove, the shear pin passes through the shear pin hole and is inserted into the shear pin groove, and the shear pin is used for fixing the piston rod.

7. The automatic-retrieving plug of claim 1, wherein The connection mode of the card seat and the base is thread connection, and the connection mode of the soluble plug and the base is thread connection.

8. The automatic-retrieving plug of claim 1, wherein The size of the soluble plug is set according to a preset dissolving time and material.

9. The automatic-retrieving plug of claim 8, wherein The material of the soluble plug is polylactic acid and / or epoxy resin.

10. A method of automatic plug retrieval, the method comprising: The application further discloses a method for using the automatic recovery type plug. S1, the automatic recovery type plug with a soluble plug with a preset size is placed into a well, and reservoir liquid flows into the throttling hole of the piston rod after the soluble plug is automatically dissolved; S2, the piston rod is pushed to go up and the clamping block is extruded into the third clamping groove after the throttling pressure difference reaches a preset value, so that the automatic recovery type plug is separated from the preset working barrel; S3, a tubing channel of a wellhead is opened to discharge, and the automatic recovery type plug returns to the wellhead under the upward thrust of the tubing working pressure difference, so that the automatic recovery is realized.

Images