CN-121993080-A - Backwashable well oil pipe plugging device for water well and use method

CN121993080ACN 121993080 ACN121993080 ACN 121993080ACN-121993080-A

Abstract

The invention discloses a plugging device for a backwashable well oil pipe and a use method thereof, comprising an outer working cylinder and a plugging core, wherein the plugging core comprises a one-way valve and a locking claw which are sequentially connected from top to bottom, the outer wall of the one-way valve is a stepped outer wall, the outer working cylinder comprises a cylindrical shell, a central channel is arranged in the cylindrical shell, the central channel is provided with a diameter-reducing step, the diameter-reducing step can be matched with the stepped outer wall, and the locking claw can be clamped with the bottom of the cylindrical shell to realize axial bidirectional positioning of the plugging core. The device adopts split design, the outer working cylinder is driven into the well along with the pipe column, the plugging core is put into the well at any time according to the later pipe column leakage condition, and the construction is convenient and simple.

Inventors

ZHANG FENG
WANG PENGFEI
ZHANG WEIWEI
LUO YANG
HUANG ZHIHONG
ZHANG ZITAN
XIAN GUOQI
ZHANG KAI
ZHANG XIAOMEI

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司胜利油田分公司

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

1. The plugging device for the backwashable oil pipe for the water well comprises an outer working cylinder and is characterized by further comprising a plugging core, wherein the plugging core comprises a one-way valve and a locking claw which are sequentially connected from top to bottom, and the outer wall of the one-way valve is a stepped outer wall; the outer working cylinder comprises a cylindrical shell, a central channel is arranged in the cylindrical shell, and the central channel is provided with a diameter-reducing step; the diameter-reducing step can be matched with the outer wall of the step, and the locking claw can be clamped with the bottom of the cylindrical shell to realize axial bidirectional positioning of the plugging core.
2. The device for plugging a backwashable well oil pipe for a well according to claim 1, wherein the check valve comprises an outer pipe and an inner pipe, the outer wall of the upper end of the inner pipe is in threaded connection with the inner wall of the lower end of the outer pipe, the lower end of the inner pipe is connected with a locking claw, a backwashable well channel is formed inside the inner pipe, and the outer pipe and the inner pipe form a stepped outer wall; The inner wall of the upper end of the outer tube is provided with an inner convex ring, the upper end of the inner tube is provided with a valve ball seat, a spring and a valve ball are sequentially arranged between the inner convex ring and the valve ball seat from top to bottom, and the spring presses the valve ball on the valve ball seat.
3. The device for plugging the backwashable oil pipe for the water well according to claim 2, wherein an upper baffle ring is arranged between the spring and the inner convex ring, and a lower baffle ring is arranged between the spring and the valve ball; the lower baffle ring is in sliding connection with the upper baffle ring through a center rod, the upper baffle ring and the lower baffle ring are hollow rings, and liquid can pass through the upper baffle ring and the lower baffle ring.
4. The apparatus for plugging a backwashable well pipe of claim 3, wherein said valve ball is made of titanium carbide, said valve ball seat is made of tungsten carbide, and said upper and lower retainer rings are cross-shaped retainer rings.
5. The device for plugging the oil pipe of the backwashable well of claim 2, wherein the outer wall of the inner pipe is provided with a first sealing ring to realize the sealing of the plugging core and the outer working cylinder, and the outer pipe and the inner pipe are sealed by using a second sealing ring.
6. The device for plugging a backwashable well tubing of claim 2, wherein said locking claw comprises at least three claw bars, gaps between said claw bars allow said claw bars to bend inwardly, and claw teeth are provided at the bottom of said claw bars; the claw teeth adopt a trapezoid structure, and conical surfaces are arranged on the outer sides of the bottom of the claw teeth, so that the claw teeth can be pressed and contracted conveniently.
7. The device for plugging the oil pipe of the backwashable well for the water well according to claim 6, wherein the corner in the diameter-reducing step is smoothly transited by using a conical surface, two stages of diameter-reducing steps are arranged in the central channel, and a large-diameter inner wall, a middle-diameter inner wall and a small-diameter inner wall are formed in the central channel from top to bottom; the large-diameter inner wall is matched with the inner wall of the outer tube, the middle-diameter inner wall is matched with the outer wall of the inner tube, and the small-diameter inner wall is matched with an outer diameter circle formed by the grabbing rod; the bottom of the central channel is a right angle, and the claw teeth are clamped with the bottom of the central channel at right angles.
8. The device for plugging a backwashable oil pipe for a water well according to claim 1, wherein an upper joint is provided at an upper end of the cylindrical housing, and a lower joint is provided at a lower end of the cylindrical housing.
9. The device for plugging a backwashable well oil pipe of claim 9, wherein the upper joint and the cylindrical shell are integrally formed, the lower joint is connected with the cylindrical shell through threads, and a third sealing ring is arranged at the joint of the lower joint and the cylindrical shell.
10. The use method of the backwashable oil pipe plugging device for the water well is characterized in that the backwashable oil pipe plugging device for the water well comprises the following steps: S1, when a well is completed, arranging a primary or multi-stage plugging device on a water injection pipe column according to actual well condition requirements and injection water quality conditions, connecting an outer working cylinder on a tool pipe string, and entering the well in advance; S2, when the plugging is needed, the plugging core is put into an oil pipe from a wellhead, the plugging core moves downwards to an outer working cylinder under the action of gravity, a locking claw is opened after passing through a diameter reduction step, and a claw tooth of the locking claw is fixed at the lower end of a central channel, so that the plugging core is fixed, and further underground sealing is completed; S3, when the water injection well is normally injected, water injection pressure from top to bottom enters the inside of the plugging core from a well flushing channel of the plugging core, the one-way valve realizes the internal sealing of the plugging device, and the first sealing ring realizes the external pressure-bearing sealing effect; s4, during back flushing, flushing fluid flows upwards from the bottom of the oil pipe, water injection pressure is increased from bottom to top, the flushing fluid enters the plugging core from the back flushing channel, flows upwards into the upper oil pipe through the one-way valve, and flows back to the ground.

Description

Backwashable well oil pipe plugging device for water well and use method Technical Field The invention relates to the technical field of oilfield water injection, in particular to a backwashable well oil pipe plugging device for a well and a use method thereof. Background In the process of water injection well layered water injection, the phenomenon that oil pipe corrosion perforation or well flushing valve ball valve seat sealing is not tight can appear in the influence of water injection oil pipe receiving corrosion, impurity and scale deposit etc. to lead to the tubular column to leak, and then influence each layer water injection quantity, lead to not reaching the injection allocation requirement, also can lead to packer sealing not tight, cause whole injection tubular column to become invalid. The existing plugging device is mostly suitable for construction of pressurized operation wells, can not back wash the well, belongs to temporary plugging measures, and is as follows: CN115126454a discloses an oil pipe plug, which comprises a delivery device, a sealing device, a locking device and an unsealing device, wherein the delivery device is connected with a working cylinder at a reference position of a downhole tubular column through a steel wire, and when the reference position is reached, the locking device locks the position of the oil pipe plug to prevent the oil pipe plug from moving up and down. The sealing device of the oil pipe plug seals the gap between the working cylinder and the oil pipe plug by using the pressure of underground liquid, and the sealing performance is enhanced along with the rise of the stratum pressure. The oil pipe blanking plug can be unlocked and sealed by using the unlocking device, so that the recovery and repeated input of the oil pipe blanking plug are realized. The blanking plug is mainly suitable for underground operation under pressure, is put into the process when underground liquid and pressure need to be sealed, and cannot meet the requirements of separate injection and backwashing after the separate injection pipe column is plugged. The publication No. CN113047804A discloses a casting-fishing type double-acting blanking plug, which comprises a preset working cylinder and a blanking plug. In the use, with presetting the working cylinder 1 access well tubular column in, follow into the well tubular column and go into in the oil gas well down, throw into the plugging device from the well head or use the steel wire to go into the well tubular column with the plugging device down, through setting up two-way seal assembly between presetting the working cylinder and top connection, realize the upper and lower two-way shutoff to oil pipe. The blanking plug is mainly suitable for underground pressurized operation construction, realizes disposable blocking, and cannot meet the requirements of separate injection and backwashing of the separated-layer water injection pipe column after blocking. The utility model discloses a CN114439423A discloses a pumping type oil pipe blocking valve and a short joint matched with the same, which is used for directly throwing in a wellhead, opening an elastic sheet after freely falling or pumping to a diameter-changing position of a seat joint to realize bidirectional limiting of a tool, realizing bidirectional separation of upper pressure and lower pressure in a pipe column through a self-sealing piece, and at the later stage, pressing down a shrinkage elastic sheet through a special salvaging tool, lifting a mandrel to shear pins, communicating the upper pressure and the lower pressure of the oil pipe blocking valve, and salvaging out a well. The blocking valve is suitable for temporarily sealing an existing operation pipe column and an opened reservoir, and can not meet the requirements of separate injection and backwashing after the separate injection pipe column is blocked. The publication number is CN216043627U, which discloses a washable well oil pipe plug, adopting a leather cup and ball seat structure. The leather cup comprises an internal metal framework and a rubber vulcanization layer vulcanized outside the metal framework, and the back flushing well is realized through ball seats connected in series inside. The patent relies on the leather cup to seal, is carried to the bottom of the well through well head pumping pressure, is only applicable to the jam of leaking to the well flushing valve in the bottom of the well, and to the leakage that appears in other places in the tubular column, the device can not realize leaking stoppage. The publication No. CN113982527A discloses a small-diameter oil pipe plug, belongs to an oil pipe blocking tool under pressure, and mainly aims at pipe column blocking under pressure operation, and is not suitable for the requirements of separate injection and backwashing after the blocking of a separate injection pipe column. For the leakage of the water injection pipe column, the requirements of lon