A long-acting production string for a CCUS response well and a construction method thereof

Abstract

The application relates to a long-acting production pipe column of a CCUS (carbon capture, utilization and storage) effect well and a construction method, and belongs to the technical field of new energy of oil and gas fields.The long-acting production pipe column of the CCUS effect well comprises a corrosion-proof oil pipe, a corrosion-proof and gas-proof pump, a gas lifting valve, an insertion seal, a plugging type on-off valve and a gas seal packer, the corrosion-proof oil pipe, the gas lifting valve and the insertion seal are sequentially threadedly connected, the insertion seal is sealingly inserted into the gas seal packer, the gas seal packer, the plugging type on-off valve and a plug are sequentially threadedly connected, and the gas seal packer is connected to the inner wall of a casing through a slip. The pipe column avoids the entry of carbon dioxide into the casing, corrosion of the casing and realizes long-acting production of the CCUS effect well. When the gas-liquid ratio in the oil pipe exceeds 500, the oil pumping pump is lifted to realize induced production, and when well washing is needed, the oil pipe is lifted to establish circulation. The pipe column can isolate carbon dioxide, reduce corrosion of the casing, has the well washing function, can protect the casing to the maximum extent during production, and effectively prolongs the service life of the production pipe column and the life cycle of the casing.

Description

Technical Field

[0001] This invention belongs to the field of new energy technology in oil and gas fields, and specifically relates to a long-term production tubing for CCUS-enabled wells. Background Technology

[0002] On the surface, CCUS technology is currently the most popular environmentally friendly development method in oil fields. It refers to CO2 capture, utilization and storage. This technology is an effective way to reduce greenhouse gas reserves, address climate change, and achieve low-carbon, green and sustainable development.

[0003] With the promotion of CCUS technology, some blocks have experienced incomplete mixing of carbon dioxide and oil due to issues such as injection pressure and formation properties. This has led to a carbon dioxide surge, resulting in increased carbon dioxide content in the produced fluid of the affected wells, which can easily cause casing corrosion.

[0004] Currently, the effective wells in the CCUS block mainly adopt gas-liquid separation under the pump, which introduces gas into the casing and controls the production of liquid carried by the casing.

[0005] The high-efficiency gas-proof lifting process is as follows:

[0006] The high-efficiency anti-gas device consists of an outer tube surrounding the oil pump, with the spiral tube connected to the lower end of the pump. This device achieves four separations before the gas and liquid enter the pump casing: first, after entering the casing, the gas and liquid undergo a first gravity settling separation in the annulus; then, the separated gas-liquid mixture enters the annulus between the oil pump and the outer tube through the liquid inlet at the top of the outer tube, resulting in a second gas-liquid separation; the gas and liquid continue to flow downwards along the annulus, and due to the density difference, a third settling separation occurs, with some gas flowing upwards and exiting through the vent hole of the outer tube; the gas and liquid flow downwards into the spiral tube at the lower end of the oil pump, resulting in a fourth centrifugal separation, with the separated gas flowing upwards through the gaps in the spiral tube and exiting through the vent hole; the separated liquid enters the oil pump through the central channel of the spiral tube.

[0007] The problems are as follows:

[0008] 1. After gas-liquid separation, carbon dioxide enters the casing, and the casing pressure needs to be monitored and controlled in real time.

[0009] 2. Carbon dioxide is corrosive, so the concentration of the corrosion inhibitor on the casing needs to be monitored in real time and replenished in a timely manner.

[0010] 3. Generally, old wells do not have the conditions for corrosion-resistant casing, and the casing is not easy to replace after corrosion. Summary of the Invention

[0011] To address the aforementioned problems, this invention proposes a long-term production tubing string for CCUS-enabled wells, comprising a corrosion-resistant tubing, a corrosion-resistant and gas-proof pump, a gas lift valve, an insertion seal, a plugging switch valve, and a gas-tight packer. The corrosion-resistant tubing, gas lift valve, and insertion seal are sequentially threaded together. The insertion seal is sealed to the gas-tight packer. The gas-tight packer, plugging switch valve, and plug are sequentially threaded together. The gas-tight packer is connected to the inner wall of the casing via slips.

[0012] Furthermore, the air lift valve includes an upper connector, a lower connector, and a sealing inner tube. The upper connector and the lower connector are threadedly connected to form the outer shell of the air lift valve, and the sealing inner tube is movably disposed on the inner wall of the upper connector.

[0013] Furthermore, the sealed inner tube is connected to the corrosion-resistant and air-proof pump.

[0014] Furthermore, the plugging switch valve includes a sealing cylinder, a sliding sealing tube, and a plug. The sealing cylinder and the plug are threadedly connected to form the outer shell of the plugging switch valve, and the sliding sealing tube is movably disposed on the inner wall of the sealing cylinder.

[0015] Furthermore, the sliding sealing tube is connected to the insertion seal.

[0016] The construction method for a long-term production string applied to a CCUS-enabled well, as described above, includes the following steps:

[0017] S1. First, the airtight packer and the plugging switch valve are lowered through the anti-corrosion oil pipe. At this time, the plugging switch valve is in the closed state. The anti-corrosion oil pipe is pressurized to set the airtight packer and then lifted up and released.

[0018] S2. Next, the air lift valve and the insert seal are lowered through the anti-corrosion oil pipe. The plugging switch valve is changed to the open state by using the key at the lower end of the insert seal. The air lift valve is in the open state.

[0019] S3. Lower the anti-corrosion and anti-air pump through the sucker rod. At this time, use the key below the anti-corrosion and anti-air pump to change the air lift valve to the closed state and start production.

[0020] It also includes the following steps: S4, when air lift is required, lift the sucker rod and open the air lift valve; lower the sucker rod and close the air lift valve.

[0021] The following steps are also included: S5. When well washing is required, the anti-corrosion tubing is raised, the insert seal and the gas seal packer are disengaged to provide a well washing channel, and the plugging switch valve is closed; the anti-corrosion tubing is lowered, and the plugging switch valve is opened.

[0022] The beneficial effects of this invention are as follows: the tubing string of this invention adopts anti-corrosion tubing, anti-corrosion and anti-gas pump, sealing switch valve, and gas-tight packer to prevent carbon dioxide from entering the casing and corroding the casing, thereby achieving long-term production of CCUS-effective wells. When the gas-liquid ratio in the tubing exceeds 500, the pump can be pulled out to induce flow production. When well washing is required, the tubing can be pulled up to establish circulation.

[0023] The tubing string of this invention can isolate carbon dioxide, reduce casing corrosion, and has a well-washing function. It can protect the casing to the greatest extent while producing, effectively improving the service life of the production tubing string and the service life of the casing. Attached Figure Description

[0024] Figure 1 This is a structural diagram of the device for the long-term production tubing string of the CCUS-enabled well according to the present invention.

[0025] Figure 2 This is a structural diagram of the air lift valve of the present invention;

[0026] Figure 3 This is a structural diagram of the plugging switch valve of the present invention;

[0027] Figure 4 This is a process flow diagram of the working process of the CCUS-enabled well long-term production tubing string of the present invention.

[0028] The attached figures are labeled as follows:

[0029] 1. Upper connector, 2. Sealing inner tube, 3. Lower connector, 4. Sealing cylinder, 5. Sliding sealing tube, 6. Plug. Detailed Implementation

[0030] To make the technical means and objectives of this invention easier to understand, the invention is further described below in conjunction with specific embodiments. A long-term production tubing string for CCUS-effective wells includes a corrosion-resistant tubing, a corrosion-resistant and gas-proof pump, a gas lift valve, an insertion seal, a plugging switch valve, and a gas-tight packer. The corrosion-resistant tubing, gas lift valve, and insertion seal are sequentially threaded together. The insertion seal is sealed and plugged into the gas-tight packer. The gas-tight packer, plugging switch valve, and plug are sequentially threaded together. The gas-tight packer is connected to the inner wall of the casing via slips.

[0031] The air lift valve includes an upper connector 1, a lower connector 3, and a sealing inner tube 2. The upper connector 1 and the lower connector 3 are threaded together to form the outer shell of the air lift valve, and the sealing inner tube 2 is movably disposed on the inner wall of the upper connector 1.

[0032] The sealed inner tube 2 is connected to the corrosion-resistant and air-proof pump.

[0033] The plugging switch valve includes a sealing cylinder 4, a sliding sealing tube 5, and a plug 6. The sealing cylinder 4 and the plug 6 are threadedly connected to form the outer shell of the plugging switch valve, and the sliding sealing tube 5 is movably disposed on the inner wall of the sealing cylinder 4.

[0034] The sliding sealing tube 5 is connected to the insertion seal.

[0035] The working process of the tubing string is as follows:

[0036] After the tubing string is lowered, the gas-sealed packer is pressurized and then a corrosion-resistant and gas-proof pump is lowered into the tubing to begin production.

[0037] By using a plug-type switching valve and a gas-tight packer, all the gas is sealed inside the oil pipe, which reduces the corrosion of the casing by carbon dioxide. The oil pipe is made of corrosion-resistant material, which can effectively resist corrosion.

[0038] When the gas-liquid ratio exceeds 500, the sucker rod is pulled out and connected to the annulus for induction and self-flowing production; when the energy is insufficient, the sucker rod is lowered in and production is lifted; when well washing is required, the tubing is pulled up, the insertion seal at the upper end of the gas-tight packer is disengaged, and the liquid inlet channel at the lower end of the gas-tight packer is closed to establish an oil-casing circulation, thereby completing the well washing operation.

[0039] tubular structure

[0040] like Figures 1-4 As shown, the tubing mainly consists of corrosion-resistant oil pipes, corrosion-resistant and air-resistant pumps, plugging-type switching valves, and airtight packers.

[0041] S1. First, the gas-tight packer and the plugging switch valve are lowered through the anti-corrosion oil pipe. At this time, the plugging switch valve is in the closed state. The anti-corrosion oil pipe is pressurized to set the gas-tight packer and then lifted up and released.

[0042] S2. Next, the air lift valve and the insert seal are lowered through the anti-corrosion oil pipe. The plugging switch valve is changed to the open state by using the key at the lower end of the insert seal. The air lift valve is in the open state.

[0043] S3. Lower the anti-corrosion and anti-air pump through the sucker rod. At this point, use the key below the anti-corrosion and anti-air pump to switch the air lift valve to the closed position. Production can then begin.

[0044] S4. When air lift is required, raise the sucker rod to open the air lift valve. Lower the sucker rod to close the air lift valve.

[0045] S5. When well washing is required, raise the tubing, disconnect the insert seal from the gas seal packer to provide a well washing channel, close the plugging switch valve, and lower the anti-corrosion tubing to open the plugging switch valve.

[0046] The connector for the anti-corrosion and anti-air pump inside the air lift valve is located below the anti-corrosion and anti-air pump. Initially, connector 3 is at the far left, and the passage is open. After the anti-corrosion and anti-air pump is lowered, the connector drives connector 3 to close the passage. If needed in the future, the anti-corrosion and anti-air pump can be lifted, causing the connector and connector 3 to move upwards, reopening the passage.

[0047] The plugging-type switch valve has an insert seal connector located below the insert seal. Initially, the sliding seal tube 5 is at the leftmost end, and the passage is closed, allowing for tubing seal pressure setting. After the insert seal is lowered, the insert seal connector moves the sliding seal tube 5 to open the passage, connecting the tubing to the formation and enabling lift production. If needed in the future, the tubing can be lifted, causing the insert seal to move upwards. The insert seal then moves the insert seal connector and sliding seal tube 5 upwards, closing the passage again for well flushing or other operations.

[0048] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A long-term production tubing string for CCUS-effective wells, characterized in that, It includes anti-corrosion oil pipe, anti-corrosion and anti-air pump, air lift valve, insertion seal, plugging switch valve, and airtight packer. The anti-corrosion oil pipe, air lift valve, and insertion seal are connected in sequence by threads. The insertion seal and the airtight packer are sealed and plugged together. The airtight packer, plugging switch valve, and plug are connected in sequence by threads. The airtight packer is connected to the inner wall of the casing by slips. The air lift valve includes an upper connector (1), a lower connector (3), and a sealing inner tube (2). The upper connector (1) and the lower connector (3) are threaded together to form the outer shell of the air lift valve. The sealing inner tube (2) is movably disposed on the inner wall of the upper connector (1). The sealed inner tube (2) is connected to the anti-corrosion and anti-air pump; The plugging switch valve includes a sealing cylinder (4), a sliding sealing tube (5), and a plug (6). The sealing cylinder (4) and the plug (6) are threadedly connected to form the outer shell of the plugging switch valve. The sliding sealing tube (5) is movably disposed on the inner wall of the sealing cylinder (4). The sliding sealing tube (5) is connected to the insertion seal; When air lift is required, raise the sucker rod to open the air lift valve; lower the sucker rod to close the air lift valve. When well washing is required, raise the anti-corrosion tubing, disconnect the insert seal from the gas seal packer to provide a well washing channel, and close the plugging switch valve; lower the anti-corrosion tubing and open the plugging switch valve.

2. A construction method for a long-term production tubing string for a CCUS-enabled well as described in claim 1, characterized in that, Includes the following steps: S1. First, the airtight packer and the plugging switch valve are lowered through the anti-corrosion oil pipe. At this time, the plugging switch valve is in the closed state. The anti-corrosion oil pipe is pressurized to set the airtight packer and then lifted up and released. S2. Next, the air lift valve and the insert seal are lowered through the anti-corrosion oil pipe. The plugging switch valve is changed to the open state by using the key at the lower end of the insert seal. The air lift valve is in the open state. S3. Lower the anti-corrosion and anti-air pump through the sucker rod. At this time, use the key below the anti-corrosion and anti-air pump to change the air lift valve to the closed state and start production. S4. When air lift is required, raise the sucker rod to open the air lift valve; lower the sucker rod to close the air lift valve. S5. When well washing is required, raise the anti-corrosion tubing, disconnect the insert seal from the gas seal packer to provide a well washing channel, and close the plugging switch valve; lower the anti-corrosion tubing and open the plugging switch valve.

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