A safe connection device for repairing casing damaged and leaking wells

Abstract

The utility model relates to a casing damage and casing leakage well repair pipe string safety connection device, which relates to the field of oil and gas development technology, and specifically to a casing damage and casing leakage well repair pipe string safety connection device, which includes an oil pipe and a safety nipple, and is characterized in that one end of the oil pipe extends into the safety nipple, and the end of the oil pipe is sealed and connected to the safety nipple through a seal sleeved on the end of the oil pipe; the safety nipple is connected to the oil pipe thread through an internal thread arranged on the top of the safety nipple; the safety nipple is provided with a pressurized channel connected to the outside, and a safety valve is provided on the pressurized channel. The utility model has a simple structure and low manufacturing cost; the construction operation is simple, safe and efficient, highly reliable, and has low construction risks; the liquid column in the oil pipe does not enter the casing, and no additional pressure is added; when a flagpole insertion accident occurs underground, the construction pipe string and the safety nipple can be quickly separated, and the upper pipe string can be safely lifted out, effectively preventing the underground accident of the construction pipe string being buried.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas development, and in particular to a safe connection device for a casing damage and casing leakage well repair pipe string. Background Art

[0002] During the long-term development of oil and gas wells, due to formation factors such as plastic deformation of the formation, engineering factors such as poor cementing and completion quality, thread loss, perforation misfire, corrosion, casing wear and other factors, the casing is damaged and failed, and the casing is lost, which greatly reduces the production of oil and gas wells, causes production layer pollution, and even causes the scrapping of oil and gas wells. These problems seriously affect the normal production of oil and gas fields, and casing damage and leakage wells must be repaired. Chemical casing repair technology is a commonly used and effective casing repair technology. Chemical casing repair technology is to inject high-strength repair agent into the damaged part of the casing. After solidification, the repaired and reinforced part has high compressive strength and good sealing. It has good chemical stability and balanced mechanical properties. The repaired casing does not shrink or change diameter. The high-strength repair agent used in the chemical casing repair technology needs to be injected into the damaged part by tools to achieve it.

[0003] Invention patent CN108798579A reports a special tool for the construction of casing repair reinforcement agent and its use method. The patent relates to a casing repair reinforcement agent construction device and its use method. The device includes three parts connected in sequence: upper, middle and lower. The middle part is a cylinder body, a piston is provided in the cylinder body, and an outlet hole is provided on the surface of the side of the cylinder body away from the lower part. The outer surfaces of the upper and lower parts are provided with packers. The piston and the packer are provided with driving devices matching them. The driving devices are connected and controlled by the electrical signal control device on the ground through cables. This patent is mainly a special tool and use method for the construction of chemical casing repair reinforcement agent to repair casing. The process does not require drilling plugs after the construction is completed, and the construction time is short. However, the equipment used in this process is relatively complex, the equipment cost is high, and the equipment is difficult to control underground. If the casing repair material solidifies prematurely, the injection tool equipment is easy to be stuck underground (commonly known as inserting a flagpole), and there is a certain risk of construction accidents. Utility Model Content

[0004] In view of the problem that the current casing repair agent injection device is easily stuck in the well and causes underground accidents, the utility model provides a casing damage and casing leakage well repair pipe string safety connection device with simple structure, simple and easy construction and operation, low cost, strong reliability, safety and high efficiency, and low construction risk. When the casing repair agent solidifies prematurely in the well and a flagpole insertion accident occurs, the device can quickly separate the oil pipe and the safety short joint injected with the casing repair agent, safely lift the upper pipe string out of the wellbore, and leave the safety short joint in the wellbore, which can be subsequently disposed of by drilling and grinding, so as to avoid the injection tool and equipment being stuck in the well when a flagpole insertion accident occurs, thereby reducing the risk of underground construction accidents.

[0005] The utility model discloses a casing damage and casing leakage well repair pipe string safety connection device, comprising an oil pipe and a safety nipple, one end of the oil pipe extends into the safety nipple, and the end of the oil pipe is sealed and connected to the safety nipple through a sealing member sleeved on the end of the oil pipe;

[0006] The safety nipple is connected to the oil pipe thread through an internal thread arranged on the top of the safety nipple;

[0007] The safety nipple is provided with a pressurized passage communicating with the outside, and the pressurized passage is provided with a safety valve;

[0008] The oil pipe is also fixedly connected to the safety short joint through a shearable pin.

[0009] Preferably, it further comprises a metal ball, a sliding sleeve is arranged in the oil pipe, the sliding sleeve is connected to the oil pipe through an elastic reset device, and a ball seat for limiting the metal ball is fixedly arranged at one end of the sliding sleeve close to the safety nipple;

[0010] When the metal ball is located at the ball seat and squeezes the metal ball seat, the sliding sleeve is driven to move, and the sliding sleeve squeezes the shear pin, and the shear pin moves radially along the oil pipe.

[0011] Preferably, the internal thread is a left-hand thread.

[0012] Preferably, two shear pins are provided, and the two shear pins are centrally symmetrically arranged about the central axis of the oil pipe.

[0013] Or preferably, the elastic reset device is a reset spring, which is sleeved on the sliding sleeve, with one end of the spring fixedly connected to the sliding sleeve and the other end of the spring fixedly connected to the oil pipe.

[0014] The utility model has a simple structure and low manufacturing cost; the construction operation is simple, safe and efficient, the reliability is strong, and the construction risk is small; the liquid column in the oil pipe does not enter the casing, and no additional pressure is added; when an underground flagpole insertion accident occurs, the construction pipe string and the safety short section can be quickly separated, and the upper pipe string can be safely pulled out, effectively preventing underground accidents in which the construction pipe string is buried.

[0015] The utility model adopts left-handed threads and shearable pins to connect the safety nipple with the oil pipe. Once the repair agent solidifies prematurely and the downhole pipe string is buried, the safety nipple can be quickly separated from the oil pipe, the upper pipe can be strung out of the wellbore, and the safety nipple can be left in the wellbore and subsequently processed by drilling and grinding, thereby avoiding construction accidents in which injection tools and equipment are stuck in the well. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the utility model.

[0017] Figure numerals: 1-metal ball, 2-oil pipe, 3-sleeve, 4-return spring, 5-left-hand thread, 6-shearable pin, 7-seal, 8-safety nipple, 9-safety valve. DETAILED DESCRIPTION

[0018] The utility model discloses a casing damage and leakage well repair pipe string safety connection device, comprising an oil pipe 2 and a safety nipple 8, one end of the oil pipe 2 extends into the safety nipple 8, and the end of the oil pipe 2 is sealed and connected to the safety nipple 8 through a sealing member 7 sleeved on the end of the oil pipe 2;

[0019] The safety nipple 8 is threadedly connected to the oil pipe 2 via an internal thread provided at the top of the safety nipple 8;

[0020] The safety nipple 8 is provided with a pressurized passage communicating with the outside, and the pressurized passage is provided with a safety valve 9;

[0021] The oil pipe 2 is also fixedly connected to the safety nipple 8 via a shearable pin 6 .

[0022] It also includes a metal ball 1, a sleeve 3 is arranged in the oil pipe 2, the sleeve 3 is connected to the oil pipe 2 through an elastic reset device, and a ball seat for limiting the metal ball 1 is fixedly arranged at one end of the sleeve 3 close to the safety nipple 8;

[0023] When the metal ball 1 is located on the ball seat and squeezes the ball seat of the metal ball 1 , the sliding sleeve 3 is driven to move, and the sliding sleeve 3 squeezes the shear pin 6 , and the shear pin 6 moves radially along the oil pipe 2 .

[0024] The internal thread is a left-hand thread 5.

[0025] There are two shear pins 6 , and the two shear pins 6 are centrally symmetrically arranged about the central axis of the oil pipe 2 .

[0026] The elastic reset device is a reset spring 4, which is sleeved on the sliding sleeve 3, and one end of the spring is fixedly connected to the sliding sleeve 3, and the other end of the spring is fixedly connected to the oil pipe 2. The sealing member 7 is a rubber ring.

[0027] like Figure 1As shown, before the casing repair agent is used to repair casing damage and leakage, the utility model is connected on the well, and the utility model is lowered into the predetermined position underground through the oil pipe 2 during the operation; when the casing repair material solidifies prematurely, causing the tool string to be buried underground by the solidified casing repair agent, and an underground flagpole insertion accident occurs, a metal ball 1 is dropped into the pipe from the wellhead, and the metal ball 1 matches the ball seat of the sliding sleeve 3. The sliding sleeve 3 compresses the reset spring 4 under the action of the metal ball 1, and the sliding sleeve 3 moves downward, and the metal ball 1 is stuck on the ball seat of the sliding sleeve 3, and then pumping and pressurizing are performed from the wellhead, the safety valve 9 is opened, the pressurized channel in the oil pipe 2 is opened, the sliding sleeve 3 pushes the shear pin 6 out of the oil pipe 2 along the radial direction of the oil pipe 2, and then the oil pipe 2 is rotated forward, that is, the oil pipe 2 is rotated in the direction opposite to the internal thread, the oil pipe 2 shears the shear pin 6, the upper pipe string and the safety short section 8 are quickly separated, and the safety short section 8 is left in the wellbore, and it is subsequently processed by drilling and grinding, which can avoid the safety accident of the injection tool and equipment being stuck in the well.

Claims

1. A casing damage and leakage well repair pipe string safety connection device, comprising a tubing and a safety nipple, characterized in that: One end of the oil pipe extends into the safety nipple, and the end of the oil pipe is sealed and connected to the safety nipple through a sealing member sleeved on the end of the oil pipe; The safety nipple is connected to the oil pipe thread through an internal thread arranged on the top of the safety nipple; The safety nipple is provided with a pressurized passage communicating with the outside, and the pressurized passage is provided with a safety valve; The oil pipe is also fixedly connected to the safety short joint through a shearable pin.

2. A casing damage and leakage well repair pipe string safety connection device as claimed in claim 1, characterized in that: It also includes a metal ball. A sliding sleeve is arranged in the oil pipe. The sliding sleeve is connected to the oil pipe through an elastic reset device. A ball seat for limiting the metal ball is fixedly arranged at one end of the sliding sleeve close to the safety nipple. When the metal ball is located at the ball seat and squeezes the metal ball seat, the sliding sleeve is driven to move, and the sliding sleeve squeezes the shear pin, and the shear pin moves radially along the oil pipe.

3. A casing damage and leakage well repair pipe string safety connection device as claimed in claim 1, characterized in that: The internal thread is a left-hand thread.

4. A casing damage and leakage well repair pipe string safety connection device as claimed in claim 1, characterized in that: The shearable pins are provided in two numbers, and the two shearable pins are centrally symmetrically arranged about the central axis of the oil pipe.

5. A casing damage and leakage well repair pipe string safety connection device as claimed in claim 2, characterized in that: The elastic reset device is a reset spring, which is sleeved on the sliding sleeve, and one end of the spring is fixedly connected to the sliding sleeve, and the other end of the spring is fixedly connected to the oil pipe.

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