A casing repair agent construction tool and construction method

Abstract

A casing repair agent construction tool and a construction method of the present invention belong to the field of oil and gas development, and relate to a casing repair agent construction tool and a construction method. A casing repair agent construction tool comprises a sealing body and a tool body which are arranged in a split manner, and the tool body comprises a hollow cylindrical first body and a hollow cylindrical second body, one end of the second body extends into the first body and is connected by a connecting device, and a sealing seat matching the sealing body is arranged in the end of the second body extending into the first body, and a through hole is arranged on the sealing seat, and the internal area of ​​the first body is connected with the internal area of ​​the second body through the through hole, and a limited position holder is also arranged on the second body; the first body and the second body of the casing repair agent construction tool of the present invention can be separated, and the first body to be removed and the drillable second body are effectively isolated, so that the risk of accidents in which the tool is stuck in the well during construction can be avoided.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas development and relates to a casing repair agent construction tool and a construction method. Background Art

[0002] During the long-term development of oil and gas wells, factors such as plastic deformation of the formation, poor cementing and completion quality, thread loss, perforation misfires, corrosion, and casing wear can lead to casing damage and failure, resulting in casing loss. This significantly reduces well production, contaminates the producing strata, and can even render the well useless. These problems severely impact the normal production of the oilfield. To maintain normal production and increase production potential, casing-damaged wells must be repaired.

[0003] Chemical casing repair technology involves displacing cement or a special chemical repair agent into the damaged section of the casing. After curing, the agent can withstand a certain pressure and exhibits good chemical stability and balanced mechanical properties. A common construction technique involves placing a suspended cement plug or a retrievable bridge plug at the base of the damaged section. The prepared repair agent is then used to seal an entire cylindrical section of the damaged section. Finally, after the agent cures, the plug is drilled and pressure tested. Disadvantages of this process include the majority of the injected casing repair agent entering the formation's lost circulation zone, potentially contaminating the formation, causing significant material loss, and making the amount of material required for repair difficult to estimate before construction. Furthermore, since the repair agent seals an entire cylindrical section of the damaged section, the material consumption is high, increasing construction costs. The amount of repair agent effectively distributed around the cement sheath, lost circulation, and casing damage is limited, resulting in low strength and a short effective life. During construction, this process lacks isolation between the construction string and the repair agent, allowing the agent to easily flow back up, potentially causing "flagpole" accidents where the construction string solidifies in the repair agent.

[0004] Invention patent CN108798579A reports a special tool for the construction of a 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 comprises three parts connected in sequence: an upper part, a middle part, and a lower part. 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 cylinder body on the side away from the lower part. The outer surfaces of the upper and lower parts are both provided with a packer. The piston and the packer are both provided with a matching drive device, and the drive device is connected to and controlled by an electrical signal control device on the ground via a cable. This invention does not require a drilling process, the process is simple, and the construction time is short. However, the equipment used in this process is relatively complex and the equipment cost is high. The equipment is difficult to control underground. If the plugging material solidifies prematurely, the equipment is easy to get stuck underground, which has a certain risk of construction accidents. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a construction process method of a casing repair agent that is simple, easy to operate, low in cost, and has low construction risk. The process method, in conjunction with a casing repair agent construction tool, can complete the construction of casing repair using a high-strength resin-based composite material casing repair agent. The construction method is simple and easy to operate.

[0006] The present invention provides a casing repair agent construction tool, comprising a sealing body and a tool body arranged in a split manner. The tool body comprises a hollow cylindrical first body and a hollow cylindrical second body. One end of the second body extends into the first body and is connected via a connecting device. A sealing seat matching the sealing body is provided in the end of the second body extending into the first body. The sealing seat is provided with a through hole. The internal area of ​​the first body is connected to the internal area of ​​the second body via the through hole. The second body is also provided with a limit seat. When the sealing body enters the sealing seat, the limit seat prevents the sealing body from leaving the seat.

[0007] A drillable packer with a circular ring shape is provided on the outer peripheral surface of the second body.

[0008] Preferably, one end of the second body away from the first body is configured as a bell mouth.

[0009] Preferably, the sealing body is a spherical sealing body, the sealing seat is a hollow hemispherical sealing seat, the sealing seat is fixedly arranged in the second body, and the center of the sphere where the sealing seat is located is located on the central axis of the second body.

[0010] Preferably, the seal is a polymer seal.

[0011] Preferably, the position limiting card seat comprises card seat bodies arranged in pairs, and the card seat bodies of the same pair are arranged in a central symmetrical manner about the central axis of the second body.

[0012] Preferably, the card seat body includes a accommodating groove and a limit block, the accommodating groove is arranged on the inner wall of the second body, the end of the limit block away from the sealing seat is rotatably connected to the inner wall of the accommodating groove through a rotating shaft, and the end of the limit block close to the sealing seat is connected to the accommodating groove through a reset spring. When the sealing body passes through the limit block, the sealing body squeezes the limit block into the accommodating groove. After the sealing body enters the sealing seat, the limit block pops out to limit the sealing body from leaving the card seat.

[0013] Preferably, the limiting block is a wedge-shaped limiting block.

[0014] Preferably, the connecting device is a pin, and the pins are arranged in pairs, and the same pair of pins are arranged in a central symmetrical manner about the central axis of the second body.

[0015] A casing repair agent construction method is provided, wherein a casing repair agent construction tool is used to construct the casing repair agent. The method is as follows:

[0016] First, a drillable bridge plug is lowered into the lower portion of the damaged or leaking casing section, and then an end of a first body of a casing repair agent application tool, which is away from the second body, is installed at the lower portion of the production tubing. Then, the casing repair agent application tool is inserted into the casing, while ensuring that the drillable packer on the casing repair agent application tool is located above the damaged or leaking casing section. The production tubing is rotated to drive the packer on the casing repair agent application tool to seat, so that the damaged or leaking casing section is located between the drillable packer and the bridge plug.

[0017] Calculate the amount of repair agent and inject the designed amount into the production tubing at the wellhead. The casing repair agent passes through the production tubing, the first body, the second body, and reaches the top of the bridge plug. As the amount of casing repair agent injected increases, the casing repair agent will fill from bottom to top. This ensures that the casing repair agent is injected evenly and densely without forming hollows. The repair agent first enters the casing damage or casing leakage area, and finally fills the confined space formed between the drillable packer and the bridge plug. The casing repair agent injection is completed.

[0018] The sealing body is dropped from the wellhead, and falls into the sealing seat after passing through the limit clamping seat. The sealing body seals the through hole on the sealing seat. When the sealing body reaches the ball seat for sealing, pressure is applied at the wellhead, and the connecting device connecting the first body and the second body is cut off. The first body and the second body are separated, and the production oil pipe is dragged to lift the first body out, and the second body remains in the well. After the casing repair agent is completely solidified, the drill plug is drilled out to remove the drillable packer and bridge plug remaining in the well, and the entire construction of the casing repair agent for casing repair is completed.

[0019] Beneficial effects of the present invention:

[0020] (1) The first body and the second body of the casing repair agent construction tool of the present invention can be separated, and the first body that needs to be removed and the second body that can be drilled are effectively isolated, thereby avoiding the risk of the tool being stuck in the well during the construction process.

[0021] (2) The present invention adopts the method of sealing with a bridge plug and sealing with a drillable packer to isolate the repair agent and the damaged or leaking casing part in a relatively closed space, which is conducive to the one-way injection of the repair agent. The effective injection volume of the repair agent in the damaged or leaking casing part and around the annulus is large, and the strength after repair is high and the effective period is long; it is convenient to estimate the amount of repair agent material in advance; it can effectively prevent the repair agent from entering the leakage zone of the formation and reduce the pollution of the repair agent to the formation; the amount of repair agent material used is small, which can reduce the cost of construction materials.

[0022] (3) The present invention adopts a sealing body and a limit seat provided with a spring to achieve bidirectional sealing, which can completely separate the repair agent and the displacement fluid after the repair agent is injected. It can prevent the displacement fluid from entering the repair section and prevent the repair agent from returning, thereby reducing the risk of "flagpole-inserting" engineering accidents in which the construction pipe string is solidified in the repair agent.

[0023] (4) The end of the second body of the present invention that is away from the first body is designed with a bell mouth, which is conducive to the smooth outflow of the repair agent; the bell mouth is designed below the casing damage or leakage part so that the repair agent reaches the upper part of the bridge plug first. As the injection amount increases, the casing repair agent will fill upward from bottom to top, which can ensure that the casing repair agent is injected evenly and densely without forming hollows.

[0024] (5) The construction method of the present invention is simple, easy to operate, has a simple construction process and low safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic diagram of the structure of a casing repair agent construction tool.

[0026] Figure 2 This is a usage status diagram of a casing repair agent construction tool.

[0027] Reference numerals: 1-wellhead, 2-casing, 3-first body, 4-sealing body, 5-pin, 6-limiting seat, 7-sealing seat, 8-drillable packer, 9-second body, 10-bell mouth, 11-drillable bridge plug, 12-casing damage or leakage part. DETAILED DESCRIPTION

[0028] The present invention provides a casing repair agent construction tool, comprising a split-type sealing body 4 and a tool body, wherein the tool body comprises a hollow cylindrical first body 3 and a hollow cylindrical second body 9, one end of the second body 9 extending into the first body 3 and connected by a connecting device, a sealing seat 7 matching the sealing body 4 is provided in the end of the second body 9 extending into the first body 3, a through hole is provided on the sealing seat 7, and the internal area of ​​the first body 3 is connected to the internal area of ​​the second body 9 through the through hole, and a limiting card seat 6 is further provided on the second body 9, and when the sealing body 4 enters the sealing seat 7, the limiting card seat 6 restricts the sealing body 4 from leaving the card seat;

[0029] A drillable packer in a circular shape is provided on the outer circumferential surface of the second body 9 .

[0030] An end of the second body 9 away from the first body 3 is provided with a bell mouth 10 .

[0031] The sealing body 4 is a spherical sealing body 4 , and the sealing seat 7 is a hollow hemispherical sealing seat 7 . The sealing seat 7 is fixedly arranged in the second body 9 , and the center of the sphere where the sealing seat 7 is located is located on the central axis of the second body 9 .

[0032] The sealing body 4 is a polymer sealing body 4 and can be a carbon fiber reinforced polyetheretherketone sealing ball.

[0033] The position limiting card seat 6 includes card seat bodies arranged in pairs, and the card seat bodies of the same pair are arranged in a central symmetric manner about the central axis of the second body 9.

[0034] The card seat body includes a accommodating groove and a limit block. The accommodating groove is arranged on the inner wall of the second body 9. The end of the limit block away from the sealing seat 7 is rotatably connected to the inner wall of the accommodating groove through a rotating shaft. The end of the limit block close to the sealing seat 7 is connected to the accommodating groove through a reset spring. When the sealing body 4 passes through the limit block, the sealing body 4 squeezes the limit block into the accommodating groove. After the sealing body 4 enters the sealing seat 7, the limit block pops out to limit the sealing body 4 from leaving the card seat.

[0035] The limit block is a wedge-shaped limit block.

[0036] The connecting device is a pin 5 , which is arranged in pairs, and the same pair of pins 5 are arranged in a central symmetrical manner about the central axis of the second body 9 .

[0037] A casing repair agent construction method, using a casing repair agent construction tool to carry out casing 2 repair agent construction, the method is as follows:

[0038] First, a drillable bridge plug 11 is lowered into the damaged or leaking casing section. Then, an end of the first body 3 of a casing repair tool away from the second body 9 is installed at the lower part of the production tubing. Then, the casing repair tool is inserted into the casing 2, while ensuring that the drillable packer 8 on the casing repair tool is located above the damaged or leaking casing section. The production tubing is rotated to drive the packer on the casing repair tool to seat, so that the damaged or leaking casing section is located between the drillable packer 8 and the drillable bridge plug 11.

[0039] Calculate the amount of repair agent used, and inject the casing 2 repair agent into the production tubing at the wellhead 1 according to the designed amount. The casing 2 repair agent passes through the production tubing, the first body 3, and the second body 9, and reaches the upper part of the drillable bridge plug 11. As the amount of casing 2 repair agent injected increases, the casing 2 repair agent will be filled from bottom to top. This ensures that the casing 2 repair agent is injected evenly and densely without forming hollows. The repair agent first enters the casing damage or casing leakage area, and finally fills the enclosed space formed between the drillable packer 8 and the drillable bridge plug 11. The injection of the casing 2 repair agent is completed.

[0040] The sealing body 4 is dropped from the wellhead 1, and the sealing body 4 falls into the sealing seat 7 after passing through the limit clamping seat 6. The sealing body 4 seals the through hole on the sealing seat 7. When the sealing body 4 reaches the ball seat seal, the wellhead 1 is pressurized, and the connecting device connecting the first body 3 and the second body 9 is cut off. The first body 3 and the second body 9 are separated, and the production oil pipe is dragged to lift the first body 3 out, and the second body 9 remains in the well. After the casing 2 repair agent is completely solidified, the drill plug drills out the drillable packer 8 and the drillable bridge plug 11 remaining in the well, and the entire construction of repairing the casing 2 with the casing 2 repair agent is completed.

[0041] Beneficial effects of the present invention:

[0042] (1) The first body 3 and the second body 9 of the casing repair agent construction tool of the present invention can be separated, and the first body 3 that needs to be removed and the second body 9 that can be drilled are effectively isolated, thereby avoiding the risk of the tool being stuck in the well during construction.

[0043] (2) The present invention adopts the method of lower sealing of drillable bridge plug 11 and upper sealing of drillable packer 8 to isolate the repair agent and the casing damage or leakage part 12 into a relatively closed space, which is conducive to the one-way injection of the repair agent. The effective injection amount of the repair agent in the casing damage or leakage part 12 and the annulus is large, and the strength after repair is high and the effective period is long; it is convenient to estimate the amount of repair agent material in advance; it can effectively prevent the repair agent from entering the formation leakage zone and reduce the pollution of the repair agent to the formation; the amount of repair agent material used is small, which can reduce the cost of construction materials.

[0044] (3) The present invention adopts a sealing body 4 and a limit holder 6 provided with a spring to achieve bidirectional sealing, which can completely separate the repair agent and the displacement fluid after the repair agent is injected. It can prevent the displacement fluid from entering the repair section and prevent the repair agent from returning, thereby reducing the risk of "flagpole-inserting" engineering accidents in which the construction pipe string is solidified in the repair agent.

[0045] (4) The end of the second body 9 of the present invention away from the first body 3 is designed with a bell mouth 10, which is conducive to the smooth outflow of the repair agent; the bell mouth 10 is designed below the casing damage or leakage part 12, so that the repair agent first reaches the upper part of the drillable bridge plug 11. As the injection amount increases, the casing 2 repair agent will be filled upward from bottom to top, which can ensure that the casing 2 repair agent is injected evenly and densely without forming hollows.

[0046] (5) The construction method of the present invention is simple, easy to operate, has a simple construction process and low safety risks.

Claims

1. A casing repair agent construction method, characterized in that: Using a casing repair agent construction tool to apply a casing (2) repair agent; A casing repair agent construction tool, comprising a split sealing body (4) and a tool body, characterized in that the tool body comprises a hollow cylindrical first body (3) and a hollow cylindrical second body (9), one end of the second body (9) extends into the first body (3) and is connected via a connecting device, a sealing seat (7) matching the sealing body (4) is arranged in the end of the second body (9) extending into the first body (3), a through hole is arranged on the sealing seat (7), the internal area of ​​the first body (3) is connected to the internal area of ​​the second body (9) via the through hole, and a limiting clamping seat (6) is also arranged on the second body (9), and when the sealing body (4) enters the sealing seat (7), the limiting clamping seat (6) limits the sealing body (4) from leaving the clamping seat; The outer circumferential surface of the second body (9) is provided with a drillable packer sleeved with a circular ring; The method is as follows: First, a drillable bridge plug is lowered into the lower part of the casing damage section or the casing leakage section, and then the end of the first body (3) of a casing repair agent construction tool away from the second body (9) is installed at the lower part of the production oil pipe, and then the casing repair agent construction tool is extended into the casing (2), while ensuring that the drillable packer (8) on the casing repair agent construction tool is located at the upper part of the casing damage section or the casing leakage section, and the end of the second body (9) is located below the casing damage or casing leakage part (12), and the production oil pipe is rotated to drive the packer on the casing repair agent construction tool to be seated, so that the casing damage section or the casing leakage section is located between the drillable packer (8) and the bridge plug; The amount of the repair agent is calculated, and the casing (2) repair agent is injected into the production tubing at the wellhead (1) according to the designed amount. The casing (2) repair agent passes through the production tubing, the first body (3), and the second body (9) to reach the upper part of the bridge plug. As the amount of the casing (2) repair agent injected increases, the casing (2) repair agent is filled upward from bottom to top, and finally fills the closed space formed between the drillable packer (8) and the bridge plug. The injection of the casing (2) repair agent is completed; A sealing body (4) is dropped from the wellhead (1), and the sealing body (4) passes through the limiting clamping seat (6) and falls into the sealing seat (7). The sealing body (4) seals the through hole on the sealing seat (7). When the sealing body (4) reaches the ball seat seal, the wellhead (1) is pressurized, and the connecting device connecting the first body (3) and the second body (9) is cut off. The first body (3) and the second body (9) are separated, and the production oil pipe is dragged to lift the first body (3), and the second body (9) remains in the well. After the casing (2) repair agent is completely solidified, the drill plug is drilled out to remove the drillable packer (8) and the bridge plug remaining in the well, and the entire construction of repairing the casing (2) with the casing repair agent is completed.

2. A casing repair agent construction method as claimed in claim 1, characterized in that: One end of the second body (9) away from the first body (3) is provided with a bell mouth (10).

3. A casing repair agent construction method as claimed in claim 1, characterized in that: The sealing body (4) is a spherical sealing body (4), the sealing seat (7) is a hollow hemispherical sealing seat (7), the sealing seat (7) is fixedly arranged in the second body (9), and the center of the sphere where the sealing seat (7) is located is located on the central axis of the second body (9).

4. A casing repair agent construction method as claimed in claim 3, characterized in that: The sealing body (4) is a polymer sealing body (4).

5. A casing repair agent construction method as claimed in claim 1, characterized in that: The position limiting clamping seat (6) comprises clamping seat bodies arranged in pairs, and the same pair of clamping seat bodies are arranged in a central symmetric manner about the central axis of the second body (9).

6. A casing repair agent construction method as claimed in claim 5, characterized in that: The seat body comprises a receiving groove and a limiting block, wherein the receiving groove is arranged on the inner wall of the second body (9), and the end of the limiting block away from the sealing seat (7) is rotatably connected to the inner wall of the receiving groove via a rotating shaft, and the end of the limiting block close to the sealing seat (7) is connected to the receiving groove via a return spring, and when the sealing body (4) passes through the limiting block, the sealing body (4) squeezes the limiting block into the receiving groove, and after the sealing body (4) enters the sealing seat (7), the limiting block pops out to limit the sealing body (4) from leaving the seat.

7. A casing repair agent construction method as claimed in claim 6, characterized in that: The limiting block is a wedge-shaped limiting block.

8. A casing repair agent construction method as claimed in claim 1, characterized in that: The connecting device is a pin (5), the pins (5) are arranged in pairs, and the same pair of pins (5) are arranged in a centrally symmetrical manner about the central axis of the second body (9).

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