Method for rheological metal temporary plugging and pressure-continuous gas production pipe string

Abstract

The application belongs to the field of oil and gas exploitation, and provides a method for continuously extracting gas by using rheological metal temporary plugging and pressure lifting, which comprises the following steps: melting and solidifying the rheological metal plugging device in the continuous gas extraction pipe column until the pipe column is sealed; connecting the pipe with the fishing tool and connecting the fishing tool with the connecting part on the continuous gas extraction pipe column; driving the continuous pipe to ascend to drive the continuous gas extraction pipe column to move to a preset position; closing the blowout preventer to clamp the continuous pipe to keep the continuous pipe at a fixed height, and sealing the pipeline below the blowout preventer and connected with the wellhead; detaching the fishing tool above the blowout preventer from the connecting part; cutting the continuous gas extraction pipe column and the connecting part; connecting the end of the connector with the continuous gas extraction pipe column and the continuous pipe; opening the blowout preventer and sealing the pipeline above the blowout preventer; and driving the continuous pipe to ascend to drive the continuous gas extraction pipe column to be lifted out of the well. The application can safely and efficiently solve the problems of sealing the continuous pipe, lifting and unblocking the continuous pipe, and winding the pipe around the roller when the pipe is lifted out of the well.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas development technology, and specifically relates to a method for pressurizing a continuous gas production tubing string by temporarily plugging it with rheological metal. Background Technology

[0002] In the process of oil and gas extraction, coiled tubing velocity string drainage and gas production technology has become one of the main drainage and gas production technologies in low-permeability oil and gas fields. However, with the continuous production of gas wells, problems such as choke failure and inability to retrieve the tubing, sand burial at the tubing head, tubing wall perforation, and corrosion fatigue gradually emerge. Removing and replacing the coiled tubing is the best option to solve these problems. Furthermore, as gas well production progresses to the later stages, due to formation energy depletion, fluid accumulation occurs again in the well, requiring the coiled tubing to be removed under pressure before other drainage and gas production processes can be carried out. However, currently, the coiled tubing removal process in China mostly adopts a method of removing the tubing without pressure after well killing. Conventional well killing and tubing removal processes affect gas well production, and the kill fluid contaminates the reservoir. In addition, the construction methods suitable for removing coiled tubing under pressure are currently complex, with long single-well operation times, and the sealing effect inside the coiled tubing is generally poor throughout the entire removal process, resulting in high safety risks. Summary of the Invention

[0003] To address the above problems, this invention proposes a method for temporarily plugging a rheometallic continuous gas production line under pressure, the method comprising:

[0004] The rheometal plug placed inside the continuous gas production string melts and solidifies until it seals the inside of the string, which is located inside the well.

[0005] After the plugging is completed, the continuous gas production tubing is pressure tested until it passes the test. Then, the continuous tubing operation device is installed at the wellhead.

[0006] The connecting pipe in the continuous tube working device is connected to the retrieval tool, and the retrieval tool is connected to the connecting part on the continuous gas sampling string.

[0007] The continuous tubing is driven to rise to move the continuous gas production string to a preset position, and the blowout preventer in the continuous tubing working device is closed to clamp the continuous tubing to keep it at a fixed height, and to seal the pipe located below the blowout preventer and communicating with the wellhead, wherein the blowout preventer is embedded in the pipe.

[0008] Remove the retrieval tool located above the blowout preventer from the connection part, and cut the connection between the continuous gas sampling string and the connection part;

[0009] The cut continuous gas sampling string is connected to one end of a connector located above it, and the other end of the connector is connected to the continuous string.

[0010] The blowout preventer is activated and the pipe above it is sealed, causing the continuous tubing to rise and pull the continuous gas production string out of the well.

[0011] Optionally, the process of melting and solidifying the rheometallic plug placed inside the continuous gas production line until the line is sealed includes:

[0012] The rheometal plug is delivered to the preset position of the continuous gas sampling string via a cable;

[0013] The cable is energized to heat the rheometal plug, which melts and solidifies within a preset temperature to seal the continuous gas extraction string.

[0014] Optionally, the step of pressure testing the sealed continuous gas production tubing until the pressure test is qualified, and then installing the continuous tubing operation device at the wellhead, includes:

[0015] A sealing test was performed on the portion of the continuous gas extraction tubing above the plug.

[0016] When the well is opened, the tubing above the continuous gas production string in the well is depressurized to 0. If the pressure does not rise within a predetermined time after the well is shut in, the sealing is successful. Otherwise, the sealing is unsuccessful and the continuous gas production string needs to be resealed until the test pressure does not rise.

[0017] The coiled tubing installation device at the wellhead shall be pressure tested until it passes the test; otherwise, the coiled tubing installation device shall be reinstalled.

[0018] Optionally, the step of connecting the connecting pipe in the continuous tubing operation device to the retrieval tool and then docking it with the connecting portion on the continuous gas production string includes:

[0019] A driving force is applied to the continuous tube, and the driving force is 5-10 times the weight of the continuous gas sampling string;

[0020] If the continuous gas production string rises, the driving force will be restored to the same weight as the continuous gas production string, thus releasing the continuous gas production string from being stuck in the well.

[0021] Optionally, the step of driving the coiled tubing upward to move the continuous gas production string to a preset position, and closing the blowout preventer in the coiled tubing working device to clamp the coiled tubing and maintain it at a fixed height, and sealing the pipe located below the blowout preventer and communicating with the wellhead, includes:

[0022] Disconnect the connected blowout preventer and injection head, and lift the disconnected injection head. The blowout preventer and injection head are part of the continuous tube operating device, wherein the blowout preventer is embedded in the blowout preventer.

[0023] Optionally, before removing the retrieval tool located above the blowout preventer from the connection and cutting the connection between the continuous gas sampling string and the connection, the following steps are included:

[0024] Release the remaining pressure inside the blowout preventer;

[0025] Depressurize at the wellhead to drive the continuous tubing up to the predetermined position;

[0026] If the leak prevention device is found to be normal within a preset time, the leak prevention device is shut off to lock the continuous tube inside the leak prevention device.

[0027] Optionally, the cut continuous gas sampling string is connected to one end of a connector located above it, and the other end of the connector is connected to the continuous tubing, including:

[0028] One end of the connector is inserted into the continuous gas sampling tubing;

[0029] The connector has a rotating shaft that can be rotated in a preset direction.

[0030] The rotating shaft rotates and presses against the sealing tube at the end of the connector to seal the sealing tube against the inner wall of the continuous gas sampling tubing.

[0031] The other end of the connector is inserted into the continuous tube.

[0032] Optionally, the step of activating the blowout preventer and sealing the pipe above it, thereby driving the coiled tubing upwards to retrieve the continuous gas production string from the well, includes:

[0033] The continuous gas sampling tubing passes through the injection head along with the continuous tubing until it is wound onto the drum. The disassembled blowout preventer is connected to the injection head. The injection head clamps the continuous tubing and drives the continuous tubing to move up and down. One end of the continuous tubing is wound onto the drum.

[0034] Optionally, the continuous gas sampling string, along with the continuous tubing, passes through the injection head until it is wound onto the drum, including:

[0035] The injection head is kept clamped in place of the continuous tube;

[0036] After the wellhead pressure is balanced, the blowout preventer embedded in the blowout preventer is opened to loosen the continuous gas production string clamped in the blowout preventer, and the injection head is connected to the blowout preventer.

[0037] The injection head drives the continuous tube upward until the continuous gas sampling string is pulled out from the port of the injection head onto the drum.

[0038] Optionally, the injection head driving the continuous tubing upwards until the continuous gas sampling string is pulled from the port of the injection head onto the roller includes:

[0039] During the ascent of the continuous gas production tubing, the wellhead pressure value during the tubing tripping process is detected;

[0040] If the pressure is not within the preset pressure range, adjust the wellhead pressure value until it meets the preset pressure.

[0041] The rising speed of the continuous gas production string is adjusted according to the distance between the end of the string and the wellhead, and the rising speed is gradually reduced until the continuous gas production string is pulled out.

[0042] The method for lifting a continuous gas production string using a rheometallic temporary plug of the present invention involves melting and solidifying a rheometallic plug placed inside the continuous gas production string until the string is sealed, thereby achieving rapid sealing of the continuous gas production string and facilitating its subsequent retrieval. A continuous tubing handling device is installed at the wellhead, allowing the entire tubing lifting process to be carried out within the device in a sealed manner. A retrieval tool is connected to the connector on the continuous gas production string, driving the tubing upwards to move the continuous gas production string to a preset position. The matching retrieval tool allows for quick and safe connection of the connector, fixing the retrieved continuous gas production string at the preset height. The blowout preventer (BOP) in the continuous tubing handling device is then closed to clamp the tubing at a fixed height and seal the pipe below the BOP that communicates with the wellhead; the BOP is embedded within the pipe. The pipe above the BOP is removed from the continuous tubing handling device to facilitate the removal of the disassembled and cut retrieval tool and connector. The continuous gas production string is then reconnected via a second sealing plug through the connecting pipe. The connector ends are connected to the continuous gas production string and the continuous tubing, respectively, to achieve secondary sealing of the continuous gas production string. This makes the retrieval of the continuous gas production string safer and more reliable. The blowout preventer is activated and the pipeline above it is sealed, driving the continuous tubing to rise and pull the continuous gas production string out of the well. The entire retrieval process is carried out in a sealed continuous tubing operation device. By first sealing the continuous gas production string and then pulling it out, the complexity of the process is simplified, the time required for single-well operation is shortened, and the sealing effect inside the continuous tubing is high throughout the retrieval process, reducing safety risks.

[0043] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This diagram illustrates the apparatus required for blocking the continuous gas production line using a rheometal temporary plug in an embodiment of the present invention.

[0046] Figure 2 A schematic flowchart of the method for pressing up a continuous gas production tubing with a rheometal temporary plug in an embodiment of the present invention is shown.

[0047] Figure 3 A schematic diagram of a rheometal device is shown in an embodiment of the present invention for a method of temporarily plugging a continuous gas production line with rheometal;

[0048] Figure 4 This diagram illustrates the docking of the retrieval tool with the continuous gas sampling tubing in the method of pressing up the continuous gas sampling tubing with a rheometallic temporary plug according to an embodiment of the present invention.

[0049] Figure 5 This diagram illustrates the sealing and lifting structure of the method for temporarily plunging a continuous gas extraction tubing with a rheometallic plug according to an embodiment of the present invention.

[0050] Figure 6 A schematic diagram of the connector for the method of pressing up a continuous gas extraction tubing with a rheometal temporary plug according to an embodiment of the present invention is shown.

[0051] In the diagram, 1. Cable trolley; 2. Ground pulley; 3. Top pulley; 4. Grease sealing head; 5. Cable blowout preventer; 6. Cable blowout preventer; 7. Reducing flange; 8. Cable; 12. Electric heating mandrel; 13. Rheological metal material; 14. Rubber support; 15. Bottom cone; 16. Coiled tubing; 17. Injection head; 18. Blowout preventer box; 19. Blowout preventer pipe; 20. Pressure relief tee; 21. Manual composite gate blowout preventer; 22. Hydraulic four-gate blowout preventer; 23. Pressure relief tee; 24. Large diameter gate valve; 25. Wellhead large four-way valve; 26. Drum; 27. Fishing tool; 28. Fishing neck; 29. ​​Hanger; 30. Connector; 31. Continuous gas production string; 32. Connector; 33. Rotary shaft; 34. Sealing sleeve. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] This invention addresses existing problems by proposing a method for lifting continuous gas sampling tubing under pressure using a rheometallic plug. The method involves melting and solidifying a rheometallic plug until the tubing is completely sealed, quickly sealing the continuous gas sampling tubing 31. This facilitates subsequent retrieval of the tubing 31. A matching retrieval tool 27 is then used to retrieve the continuous gas sampling tubing 31 and its connecting parts. The connection between the connecting pipe 16 and the continuous gas sampling tubing 31 is controlled on the ground, and the roller 26 rewinds the continuous pipe 16 back to the ground. This solves the problems existing in current methods for lifting continuous gas sampling tubing 31 under pressure. However, this method requires the cooperation of certain devices or components, such as… Figure 1As shown, the wellhead facilities include a cable trolley 1, a ground pulley 2, a top pulley 3, a grease-sealing head 4, a cable blowout preventer 5, a cable blowout preventer 6, a reducing flange 7, and a cable 8. The cable trolley 1 has a roller with the cable 8 installed on it, which is responsible for raising and lowering the cable 8. The cable 8 is transported to the grease-sealing head 4 and the cable blowout preventer 5 through the ground pulley 2 fixed at the wellhead and the top pulley 3 lifted by the crane. The grease-sealing head 4 and the cable blowout preventer 5 are responsible for sealing the pressure inside the well when the cable 8 is moving. The cable blowout preventer 6 is responsible for sealing the pressure inside the well when the cable 8 stops being raised or lowered. The reducing flange 7 converts the flange at the wellhead into a threaded connection that can be connected to the cable sealing device 6. The grease-sealing head 4, the cable blowout preventer 5, and the cable sealing device 6 are connected by threads. The grease-sealing head 4, the cable blowout preventer 5, the cable sealing device 6, and the reducing flange 7 are connected in sequence. The reducing flange 7 is connected to the flange at the wellhead and is located above the wellhead. When the rheometallic plug is placed inside the continuous gas production string 31, and the rheometallic plug inside the continuous gas production string 31 is melted and allowed to solidify until the string is sealed, the above-mentioned components need to be installed at the wellhead in sequence. When the sealing is completed, the components need to be removed and a continuous tubing operation device needs to be installed at the wellhead. The continuous tubing operation device includes a continuous tubing 16, and sequentially connected components such as an injection head 17, a blowout preventer box 18, a blowout preventer pipe 19, a pressure relief tee 20, blowout preventers (including a manual composite gate blowout preventer 21 and a hydraulic four-gate blowout preventer 22), a pressure relief tee 23, a large-diameter gate valve 24, and a wellhead large four-way valve 25. The wellhead large four-way valve 25 is installed at the wellhead. The continuous gas production string 31 in the well is retrieved through the above-mentioned components. Specifically, one end of the coiled tubing 16 is wound onto the drum 26, and the other end passes sequentially through the injection head 17 blowout preventer box, blowout preventer pipe 19, pressure relief tee 20, manual composite gate blowout preventer 21, hydraulic four-gate blowout preventer 22, pressure relief tee 23, large-diameter gate valve 24, and wellhead large four-way connector 25 until it enters the well and connects to the connection part on the continuous gas production string 31 via the retrieval tool 27. The injection head 17 can clamp the coiled tubing 16 and raise or lower it, thereby causing the continuous gas production string 31 to rise. Because all components are interconnected, the entire process is carried out in a sealed environment. The pressure relief tee 20, pressure relief tee 23, large-diameter gate valve 24, and wellhead large four-way connector 25 can regulate the well pressure.

[0054] like Figure 2 As shown, the present invention provides a method for pressurizing a continuous gas production string using a rheometallic temporary plug, comprising:

[0055] In step S10, the rheometallic plug placed inside the continuous gas production string 31 melts and solidifies until it seals the inside of the string, placing the continuous gas production string 31 inside the well. It should be noted that before sealing the continuous gas production string 31, a gauge with the same outer diameter as the rheometallic plug is used. With the wellhead pressurized, the gauge is lowered into the continuous gas production string 31 using a cable device to confirm the inner diameter of the string. This facilitates the next step of placing the rheometallic plug to seal the continuous gas production string 31. If the gauge can be successfully lowered into the continuous gas production string, the rheometallic plug will also be successfully lowered into the predetermined position inside the continuous gas production string 31. Furthermore, the purpose of sealing the continuous gas production string 31 is to prevent gas pressure from continuously entering the continuous gas production string 31. In order to achieve pressurized tubing tripping, a rheometallic plug needs to be deployed to block the inside of the continuous gas production string 31, preventing pressurized fluid from entering the continuous gas production string 31 and ensuring that the pressure inside the continuous gas production string 31 is consistent with the surface pressure. This facilitates the subsequent disconnection of the continuous gas production string 31 and the surface continuous tubing 16 in an atmospheric pressure environment. Of course, during disconnection, the injection head 17 and the blowout preventer 19 above the wellhead need to be disassembled first, so that the continuous gas production string 31 is exposed from the blowout preventer 19. The rheometallic plug is used to seal the channel inside the continuous tubing, providing well control conditions for removing the production (gas) tree and replacing the wellhead and blowout preventer, while preventing gas from escaping from the continuous tubing during the tubing tripping process.

[0056] In one embodiment, the process of melting and solidifying the rheometallic plug placed inside the continuous gas production string 31 until the string is sealed includes:

[0057] The rheometallic plug is delivered to a predetermined position within the continuous gas sampling string 31 via a cable. Specifically, the rheometallic plug is lowered to a position approximately 50 meters inside the continuous gas sampling string 31. For example... Figure 3 As shown, the rheometallic plug includes a heating mandrel 12, a rheometallic material 13, a rubber support 14, and a bottom cone 15.

[0058] The cable is energized and heats the rheometallic plug, causing it to melt and solidify within a preset temperature, sealing it within the continuous gas extraction string 31. For example... Figure 3As shown, the electric heating mandrel 12 is heated by the energized cable, reaching a temperature of approximately 350 degrees Celsius, the melting point of the rheometallic material 13. The electric heating mandrel 12 is positioned at the center of the rheometallic material 13, effectively encasing it. At approximately 350 degrees Celsius, the rheometallic material 13 melts completely, adhering to the internal gaps of the continuous gas extraction string 31. The rubber support 14 and the bottom cone 15 support the molten rheometallic material 13, preventing it from flowing below them. The end of the rheometallic material 13 is positioned on the rubber support 14, which is connected to the bottom cone 15. The rubber support 14 holds the molten material, ultimately blocking the continuous gas extraction string 31. It should be noted that when heating with electricity, the cable 8 needs to be energized to melt the rheological metal material 13. After it is completely melted, the cable 8 is de-energized and the rheological metal material 13 is allowed to solidify to form a fixed metal object that blocks the continuous gas sampling column 31. After the continuous gas production string 31 is successfully plugged, it can be started. Some other components are required. Of course, the cable trolley 1, ground pulley 2, top pulley 3, grease sealing head 4, cable blowout preventer 5, cable well sealer 6, reducing flange 7, and cable 8 need to be removed and replaced with other components connected to the wellhead flange, such as the wellhead four-way valve 25, and the large-diameter gate valve 24 connected to the wellhead four-way valve 25, the continuous tubing 16, and the injection head 17, blowout preventer box 18, blowout preventer 19, pressure relief tee 20, blowout preventer (including manual composite gate blowout preventer 21 and hydraulic four-gate blowout preventer 22), pressure relief tee 23, etc. These components are used to start the continuous gas production string 31.

[0059] In addition, the metal shell is made of bismuth alloy rheometallic plug, which is electrically controlled from the ground to change from solid to liquid. It has a good penetration and filling effect, and can pass through damaged or squeezed reduced diameter sections of the tubing. After solidification, it can achieve annular seal between metals, and has the gas sealing capability that cement plugging cannot achieve. It can be widely used in various tubing plugging operations.

[0060] The rheological metal plugging device is made of a bismuth alloy with good low-temperature (adjustable from 90 - 263 °C) rheological properties. It is lowered into the well by cable 8, and heat energy is provided for melting the bismuth-based alloy through ground power supply to achieve the "solid-liquid-solid" phase transformation. During the plugging operation, the rheological metal plugging device is lowered to a predetermined position inside the pipe string. With ground power supply, the solid metal melts into a liquid state, settles on the upper part of the bottom support, penetrates and fills the space above the bottom support. When the ground power supply stops, the liquid metal cools and solidifies to form a metal plug to complete the plugging of the pipe string. Specifically, power is supplied for 30 - 50 minutes, heating until the rheological metal material 13 is completely liquefied, then the ground power supply stops. Ensure that the cable pressure control does not leak, the wellhead seal is reliable, and the plugging device is allowed to coagulate for 4 - 12 hours. The rheological metal plugging device is pressure-tested at 25 Mpa, and if the pressure drop is less than 0.5 Mpa in 30 minutes, it is considered qualified. Of course, when the sealing is completed, other devices such as the redundant electric heating mandrel 12 need to be removed.

[0061] Step S20, pressure-test the continuous gas production pipe string 31 after plugging until the pressure test is qualified, and install a coiled tubing operation device at the wellhead. The continuous gas production pipe string 31 is pressure-tested for plugging to clearly know whether the plugging is successful at any time. In order to be able to lift the pipe under pressure, a rheological metal plugging device needs to be put in to block the inside of the continuous gas production pipe string 31 in the well. The continuous gas production pipe string 31 must be tightly blocked to prevent the pressurized fluid in the well from entering the inside of the continuous gas production pipe string 31, making the pressure inside the continuous gas production pipe string 31 consistent with the ground pressure, which is convenient for subsequent pipe lifting.

[0062] In one embodiment, pressure-testing the continuous gas production pipe string 31 after plugging until the pressure test is qualified and installing a coiled tubing operation device at the wellhead includes:

[0063] Conduct a plugging seal test on the part above the plugging of the continuous gas production pipe string 31;

[0064] Open the well to relieve the pressure of the tubing above the continuous gas production pipe string 31 in the well to 0. After closing the well, if the pressure does not rise within a predetermined time, the plugging is successful; if otherwise, the plugging is unsuccessful, and the continuous gas production pipe string 31 needs to be re-plugged until the test pressure does not rise. It should be noted that whether the internal plugging of the continuous gas production pipe string 31 is successful is tested from the wellhead pressure. If the wellhead pressure gate is closed again and observed for 30 minutes, and the wellhead pressure does not rise, it means that the internal plugging of the continuous gas production pipe string 31 is successful and the condition for lifting the continuous gas production pipe string 31 in the well is met; otherwise, the condition for lifting the continuous gas production pipe string in the well is not met, and re-plugging and re-pressure testing are required until the pressure test is qualified.

[0065] Conduct a pressure test operation on the coiled tubing operation device installed at the wellhead until it is qualified; otherwise, the coiled tubing operation device needs to be reinstalled. By detecting the pressure inside the coiled tubing operation device, it is convenient for subsequent safe pipe lifting.

[0066] Step S30: Connect the connecting pipe 16 in the continuous tubing operation device to the retrieval tool 27, and then connect the retrieval tool 27 to the connecting part on the continuous gas production string 31. For example... Figure 4 As shown, during the docking process, the connecting pipe 16 connected to the retrieval tool 27 needs to be lowered close to one end of the continuous gas sampling string 31 until the retrieval tool 27 is successfully docked with the connecting part. Figure 4 As shown, the connection includes a suspension neck 28, a suspension 29, and a connector 30 connected in sequence. The continuous gas production string 31 is connected to the connector 30, and the retrieval tool 27 is connected to the suspension neck 28. Once the retrieval tool 27 successfully retrieves the suspension neck 28, the continuous gas production string 31 inside the well is connected to the continuous tubing 16 on the surface via the connector 30 and the suspension 29. This facilitates the subsequent lifting of the continuous gas production string 31.

[0067] In one embodiment, after connecting the connecting pipe 16 in the coiled tube working device to the retrieval tool 27 and docking it with the connecting portion on the coiled gas production string 31, the process includes:

[0068] A driving force is applied to the continuous tube 16, and the driving force is 5-10 times the weight of the continuous gas sampling string 31.

[0069] If the continuous gas production string 31 rises, restore the driving force to the same weight as the continuous gas production string 31 to release it from the well. It should be noted that while the driving force can propel the continuous gas production string 31 upwards, the retrieval tool 27 should be slowly lifted. First, apply a force greater than 5 tons of the continuous gas production string 31's own weight to the retrieval tool 27 and observe for 5-10 minutes. During this process, to prevent the continuous gas production string 31 from being lifted, apply a driving force greater than 5 tons of its own weight, as the continuous gas production string 31 may have become connected to the well bottom after being in the well for a long time. It is necessary to first separate the continuous gas production string 31 from the well bottom surface. Once separation is confirmed, restore the applied driving force to the same weight as the continuous gas production string 31.

[0070] Step S40: The coiled tubing 16 is driven upward to move the continuous gas production string 31 to a preset position. The blowout preventers (manual composite gate blowout preventer 21 and hydraulic four-gate blowout preventer 22) in the coiled tubing working device are then closed to clamp the coiled tubing 16 at a fixed height and to seal the pipe connected to the wellhead below the blowout preventer, which is embedded within the pipe. All operations of the continuous gas production string 31 are performed within the coiled tubing working device. Raising the continuous gas production string 31 to the preset height facilitates the subsequent disassembly of the retrieval tool 27 and the various connecting components on the continuous gas production string 31. Figure 5As shown, it should be noted that this process is carried out in a sealed manner within the sequentially connected injection head 17, blowout preventer box 18, blowout preventer pipe 19, pressure relief tee 20, blowout preventer devices (including manual composite gate blowout preventer 21 and hydraulic four-gate blowout preventer 22), pressure relief tee 23, large-diameter gate valve 24, and wellhead large cross-connector 25. The wellhead large cross-connector 25 is sealed within the well. The blowout preventer pipe 19 is connected to the injection head 17 through the blowout preventer box 18. The continuous tubing 16 passes sequentially through the injection head 17, blowout preventer box 18, blowout preventer pipe 19, pressure relief tee 20, blowout preventer devices (manual composite gate blowout preventer 21 and hydraulic four-gate blowout preventer 22), pressure relief tee 23, large-diameter gate valve 24, and wellhead large cross-connector 25. The wellhead large cross-connector 25 is connected to the continuous gas production string 31 in the well. The injection head 17 can drive the continuous tubing 16 to move up and down.

[0071] In one embodiment, driving the coiled tubing 16 upward to move the continuous gas production string 31 to a preset position, and closing the blowout preventer in the coiled tubing working device to clamp the coiled tubing 16 to maintain it at a fixed height, and sealing the pipe located below the blowout preventer and communicating with the wellhead, includes:

[0072] Disconnect the connected blowout preventer 19 and injection head 17, and lift the disconnected injection head 17. The blowout preventer 19 and injection head 17 are part of the coiled tubing operating device, wherein the blowout preventer is embedded within the blowout preventer 19. It should be noted that the coiled tubing operating device includes a blowout preventer 19 and an injection head 17, and the blowout preventer 19 is connected to the injection head 17. Specifically, as... Figure 5 As shown, the continuous gas production string 31 in the well is pulled out of the well by driving the coiled tubing 16 through the injection head 17. The hanger 29, the fishing neck 28, and the fishing tool 27 are placed in the blowout preventer 19 above the blowout preventer (manual composite gate blowout preventer 21 and hydraulic four-gate blowout preventer 22) and below the blowout preventer box 18. The manual composite gate blowout preventer 21 and the hydraulic four-gate blowout preventer 22 are embedded in the blowout preventer 19. When the manual composite gate blowout preventer 21 and the hydraulic four-gate blowout preventer 22 are closed, the continuous gas production string 31 in the blowout preventer 19 can be temporarily fixed, that is, the continuous gas production string 31 can be clamped in the blowout preventer 19. At the same time, the blowout preventer 19 can be sealed, thereby preventing gas in the well from leaking out through the blowout preventer 19.

[0073] In step S50, the retrieval tool 27, located above the blowout preventer (BOP), is detached from the connector, and the connection between the continuous gas production string 31 and the connector is cut. When the continuous gas production string 31 rises to the preset height, the continuous gas production string 31 is cut from the connector, and the retrieval tool 27 is detached from the connector. This operation is to remove the retrieval tool 27 and connector, as the continuous gas production string 31 needs to be passed directly through the injection head 17 later. Due to the large size of the retrieval tool 27 and connector, they cannot pass directly through the inside of the injection head 17; therefore, the retrieval tool 27 and connector need to be detached and removed. After the retrieval tool 27 and connector are detached, the BOP 19 connected to the injection head 17 needs to be disconnected, thereby exposing and removing the retrieval tool 27 and connector. During this process, the BOP clamps the continuous tubing to maintain a fixed height and seals the pipe below the BOP that communicates with the wellhead; therefore, the entire operation remains sealed.

[0074] Furthermore, the blowout preventer 19 connected to the injection head 17 is disconnected. It should be noted that before disconnecting the blowout preventer 19 connected to the injection head 17, the hydraulic four-gate blowout preventer 22 in the blowout preventer device needs to be closed, the continuous gas sampling string 31 needs to be suspended and fixed and the annular pressure below the continuous gas sampling string 31 and the hydraulic suspension device 22 needs to be sealed, and then the manual compound gate blowout preventer 21 in the blowout preventer device needs to be closed. The manual compound gate blowout preventer 21 and the hydraulic four-gate blowout preventer 22 together suspend and fix the continuous gas sampling string 31 and seal the annular pressure below the continuous gas sampling string 31 and the hydraulic four-gate blowout preventer 22, thereby increasing the sealing effect.

[0075] Remove the salvage tool 27 exposed outside the blowout preventer 19. Specifically, pump clean water into the continuous tube 16 to pressurize it and slowly lift the continuous tube 16. The pressure inside the continuous tube 16 causes the front fixing rivet of the salvage tool 27 to retract and separate from the step that cooperates with the salvage neck 28, and the salvage tool 27 is taken out from the blowout preventer 19.

[0076] Cut the connection between the continuous gas sampling tubing 31 and the connecting part, and remove the connecting part. Specifically, chamfer the inside and outside of the upper end of the continuous gas sampling tubing 31 at 45°, remove the tube neck and burrs, and facilitate the connection with the reconnection tool for connecting to the continuous tubing 16.

[0077] In one embodiment, before removing the retrieval tool 27 located above the blowout preventer from the connector and cutting the connection between the continuous gas sampling string 31 and the connector, the following steps are included:

[0078] The remaining pressure in the blowout preventer 19 is released, and the continuous gas intake string 31 is locked in the blowout preventer 19 by the blowout preventer device. It should be noted that a pressure relief tee 20 is also provided on the blowout preventer 19. The remaining pressure in the blowout preventer 19 above the blowout preventer device is released by the pressure relief tee 20, which facilitates the disassembly of the blowout preventer 19 and the injection head 17.

[0079] After depressurizing at the wellhead, drive the coiled tubing 16 to the predetermined position. When the wellhead pressure is balanced, release the blowout preventer. At the same time, slowly lift the coiled tubing 16 to separate the fishing tool 27 from the connection part, lift and remove the injection head 17, and use a manual cutter to cut the continuous gas production string 31 along the root of the connector below the connection part.

[0080] If the seal of the blowout preventer 19 is found to be normal within a preset time, the blowout preventer is closed to lock the continuous production tubing 16 inside the blowout preventer 19. This ensures that the connection of the blowout preventer 19 is under normal pressure, facilitating the connection of the connecting tubing 16 to the cut continuous production tubing 31, and also preventing gas from flowing out of the well. Specifically, pressure is released through the stopcock valve on the pressure relief tee 20, and if the seal is found to be normal after 15 minutes, the blowout preventer is closed.

[0081] In step S60, the cut continuous gas sampling string 31 is connected to one end of the connector 32 located above it, and the other end of the connector 32 is connected to the continuous tube 16. It should be noted that, as... Figure 6 As shown, when connector 32 completes its connection with continuous gas production string 31 and continuous tubing 16, blowout preventer 19 needs to be reconnected to injection head 17 via blowout preventer box 18, so that blowout preventer 19 is connected to injection head 17 again. Additionally, by driving continuous tubing 16, connector 32 is raised, thereby raising continuous gas production string 31.

[0082] In one embodiment, the cut continuous gas sampling string is connected to one end of a connector 32 located above it, and the other end of the connector 32 is connected to the continuous tubing 16, including:

[0083] One end of connector 32 is inserted into continuous gas sampling tubing 31;

[0084] The rotating shaft 33 in the connector 32 rotates in a preset direction. It should be noted that rotating the rotating shaft 33 allows the sealing end on the connector 32 to be tightly fitted into the continuous gas sampling string 31. In addition, the rotating shaft 33 is located at the center of the connector 32.

[0085] The rotating shaft 33 rotates and presses against the sealing tube at the end of the connector 32 to seal the sealing tube against the inner wall of the continuous gas sampling string 31. Under the rotation of the rotating shaft 33, the sealing tube can eventually be tightly attached to the inner wall of the continuous gas sampling string 31, thus achieving a seal on the continuous gas sampling string 31.

[0086] The other end of connector 32 is inserted into continuous tube 16.

[0087] Step S70: Activate the blowout preventer (BOP) and seal the piping above it. Specifically, connect the BOP pipe 19 and BOP box 18 above the BOP to the injection head 17, driving the coiled tubing 16 upwards to pull the continuous gas production string 31 out of the well. The injection head 17 drives the coiled tubing 16 upwards, pulling the continuous gas production string 31 through the injection head 17 until it is wound onto the roller 26. Since the entire tubing pulling process is carried out in a sealed environment, and pressure exists both inside the well and within the continuous gas production string, sealing the continuous gas production string before pulling it out will not affect gas well production and will also avoid contamination of the kill fluid reservoir.

[0088] In one embodiment, activating the blowout preventer and sealing the pipe above it, driving the coiled tubing 16 upward to pull the continuous gas production string 31 out of the well includes:

[0089] The continuous gas sampling tube 31 passes through the injection head along with the continuous tube 16 until it is wound onto the drum 26. The disassembled blowout preventer 19 is connected to the injection head 17. The injection head 17 clamps the continuous tube 16 and drives the continuous tube 16 to rise and fall. One end of the continuous tube 16 is wound onto the drum 26.

[0090] Specifically, during this process, the injection head 17 is kept clamped to the continuous tube 16. By clamping the continuous tube 16, it is easier for the injection head 17 to subsequently drive the continuous tube 16 to move upward. The injection head 17 can achieve tube raising and lowering by clamping the continuous tube 16 itself. Clamping is to lift the continuous tube 16 to reduce the weight of the continuous gas production string 31 borne by the manual composite gate blowout preventer 21 and the hydraulic four-gate blowout preventer 22, making it easier to open the manual composite gate blowout preventer 21 and the hydraulic four-gate blowout preventer 22 in the next step.

[0091] After the wellhead pressure is balanced, the blowout preventers (manual composite gate blowout preventer 21 and hydraulic four-gate blowout preventer 22) embedded in the blowout preventer 19 are opened to release the continuous gas production string 31 clamped inside the blowout preventer 19, and the injection head 17 is connected to the blowout preventer 19. The manual composite gate blowout preventer 21 is released first, followed by the hydraulic four-gate blowout preventer 22, for ease of operation. Releasing the manual composite gate blowout preventer 21 first is relatively easier, at which point the hydraulic four-gate blowout preventer 22 bears the weight of the continuous gas production string 31. The continuous gas production string 31 can be suspended through the injection head 17.

[0092] The injection head 17 drives the continuous tube 16 to rise until the continuous gas sampling string 31 is pulled out from the port of the injection head 17 onto the drum 26.

[0093] In one embodiment, the injection head 17 drives the continuous tubing 16 upward until the continuous gas sampling string 31 is pulled from the port of the injection head 17 onto the roller 26, including:

[0094] During the ascent of the continuous gas production tubing 31, the wellhead pressure value during the tubing tripping process was monitored.

[0095] If the pressure is not within the preset range, adjust the wellhead pressure until it meets the preset pressure. Monitoring and adjusting the pressure are both for the smooth running of the tubing. If the pressure does not meet the requirements, it will hinder the running of the tubing and make it inconvenient.

[0096] The rising speed of the continuous gas production string 31 is adjusted according to the distance between its end and the wellhead, gradually decreasing until the string is pulled out. Specifically, when the continuous gas production string 31 is 500m from the wellhead, the pulling speed is reduced to 10m / min; when it is 200m from the wellhead, the speed is reduced to 5m / min; when it is 100m from the wellhead, the speed is reduced to 1-2m / min; and finally, when it is 50m from the wellhead, the wellhead main valve 24 is closed every 5m of string pulled out until it is pulled out. It should be noted that pressure needs to be released during string pulling. This is achieved through the coordinated adjustment of the pressure relief tee 20, the blowout tee 23, the wellhead main valve 24, and the wellhead large four-way valve 25 to release pressure in the gas production string and within the well. The pressure relief tee 20, the blowout tee 23, the wellhead main valve 24, and the wellhead large cross 25 are connected to a single pipe. This pipe is connected to the blowout preventer pipe 19, and the wellhead large cross 25 is connected to the flange on the wellhead.

[0097] In summary, using rheometallic plugging tools for internal plugging is highly applicable, unaffected by the unique flexural characteristics of the coiled tubing 16 or irregular weld seams on its inner wall. The matching hanging retrieval tool 27 allows for quick and safe docking and retrieval of the continuous gas production string 31 connection. The pipe-to-pipe docking tool ensures safer and more reliable secondary plugging of the continuous gas production string 31. The entire pipe pulling process is conducted in a sealed environment, with pressure present both inside the well and within the continuous gas production string. By first plugging the continuous gas production string and then pulling it out, the wellbore remains pressurized throughout the operation. Compared to conventional well control and pipe pulling without pressurization after injection, this method has less impact on gas well production, avoids reservoir contamination by the kill fluid, and avoids the difficulties and high costs associated with later fluid drainage in some wells. By first plugging the continuous gas production string and then pulling it out, the process complexity is simplified, reducing the time required for single-well operations. Furthermore, the sealing effect within the coiled tubing is high throughout the entire pipe pulling process, reducing safety risks.

[0098] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for temporarily plugging a continuous gas production tubing with rheometallic material under pressure, characterized in that, The method includes: The rheometal plug placed inside the continuous gas production string melts and solidifies until it seals the inside of the string, which is located inside the well. After the plugging is completed, the continuous gas production tubing is pressure tested until it passes the test. Then, the continuous tubing operation device is installed at the wellhead. The connecting pipe in the continuous tube working device is connected to the retrieval tool, and the retrieval tool is connected to the connecting part on the continuous gas sampling string. The continuous tubing is driven to rise to move the continuous gas production string to a preset position, and the blowout preventer in the continuous tubing working device is closed to clamp the continuous tubing to keep it at a fixed height, and to seal the pipe located below the blowout preventer and communicating with the wellhead, wherein the blowout preventer is embedded in the pipe. The pipe above the blowout preventer is removed from the continuous pipe working device, the retrieval tool is removed from the connection, and the connection between the continuous gas sampling string and the connection is cut. The cut continuous gas sampling string is connected to one end of a connector located above it, and the other end of the connector is connected to the continuous string. The blowout preventer is activated and the pipe above it is sealed, causing the continuous tubing to rise and pull the continuous gas production string out of the well.

2. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, The process of melting and solidifying the rheometal plug placed inside the continuous gas production string until the string is sealed includes: The rheometal plug is delivered to the preset position of the continuous gas sampling string via a cable; The cable is energized to heat the rheometal plug, which melts and solidifies within a preset temperature to seal the continuous gas extraction string.

3. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, The process of pressure testing the continuous gas production tubing after sealing until the test is successful, and then installing the continuous tubing workpiece at the wellhead, includes: A sealing test was performed on the portion of the continuous gas extraction tubing above the plug. When the well is opened, the tubing above the continuous gas production string in the well is depressurized to 0. If the pressure does not rise within a predetermined time after the well is shut in, the sealing is successful. Otherwise, the sealing is unsuccessful and the continuous gas production string needs to be resealed until the test pressure does not rise. The coiled tubing installation device at the wellhead shall be pressure tested until it passes the test; otherwise, the coiled tubing installation device shall be reinstalled.

4. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, The step of connecting the connecting pipe in the coiled tube working device to the retrieval tool and then docking it with the connecting part on the coiled gas production string includes: A driving force is applied to the continuous tube, and the driving force is 5-10 times the weight of the continuous gas sampling string; If the continuous gas production string rises, the driving force will be restored to the same weight as the continuous gas production string, thus releasing the continuous gas production string from being stuck in the well.

5. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, The process of driving the coiled tubing upward to move the continuous gas production string to a preset position, and then closing the blowout preventer in the coiled tubing working device to clamp the coiled tubing and maintain it at a fixed height, and sealing the pipe located below the blowout preventer and communicating with the wellhead, includes: Disconnect the connected blowout preventer and injection head, and lift the disconnected injection head. The blowout preventer and injection head are part of the continuous tube operating device, wherein the blowout preventer is embedded in the blowout preventer.

6. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, Before removing the retrieval tool located above the blowout preventer from the connection and cutting the connection between the continuous gas sampling string and the connection, the following steps are included: Release the remaining pressure inside the blowout preventer; Depressurize at the wellhead to drive the continuous tubing up to the predetermined position; If the leak prevention device is found to be normal within a preset time, the leak prevention device is shut off to lock the continuous tube inside the leak prevention device.

7. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, The cut continuous gas sampling tubing is connected to one end of a connector located above it, and the other end of the connector is connected to the continuous tubing, including: One end of the connector is inserted into the continuous gas sampling tubing; The connector has a rotating shaft that can be rotated in a preset direction. The rotating shaft rotates and presses against the sealing tube at the end of the connector to seal the sealing tube against the inner wall of the continuous gas sampling tubing. The other end of the connector is inserted into the continuous tube.

8. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, The step of activating the blowout preventer and sealing the pipe above it, thereby driving the coiled tubing upwards to retrieve the continuous gas production string from the well, includes: The continuous gas sampling tubing passes through the injection head along with the continuous tubing until it is wound onto the drum. The disassembled blowout preventer is connected to the injection head. The injection head clamps the continuous tubing and drives the continuous tubing to move up and down. One end of the continuous tubing is wound onto the drum.

9. The method for temporarily plugging and pressurizing a continuous gas production tubing with rheometallic material according to claim 1, characterized in that, The continuous gas extraction tubing, along with the continuous tubing, passes through the injection head until it is wound onto the drum, including: The injection head is kept clamped in place of the continuous tube; After the wellhead pressure is balanced, the blowout preventer embedded in the blowout preventer is opened to loosen the continuous gas production string clamped in the blowout preventer, and the injection head is connected to the blowout preventer. The injection head drives the continuous tube upward until the continuous gas sampling string is pulled out from the port of the injection head onto the drum.

10. The method for temporarily plugging and pressurizing a continuous gas production string with rheometallic material according to claim 9, characterized in that, The injection head drives the continuous tubing upward until the continuous gas sampling string is pulled out from the port of the injection head onto the roller, including: During the ascent of the continuous gas production tubing, the wellhead pressure value during the tubing tripping process is detected; If the pressure is not within the preset pressure range, adjust the wellhead pressure value until it meets the preset pressure. The rising speed of the continuous gas production string is adjusted according to the distance between the end of the string and the wellhead, and the rising speed is gradually reduced until the continuous gas production string is pulled out.

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