A sustained-release cleanup agent integrated column and a cleanup agent supplementing method

Abstract

The application provides a slow-release cleanup agent integrated pipe column and a cleanup agent supplementing method, relates to the technical field of oil and gas field exploitation, and comprises a base pipe unit, a porous slow-release carrier layer, a pre-impregnated cleanup agent and a medicament supplementing unit. The base pipe unit is a pipe body with a hollow interior and open ends. The porous slow-release carrier layer is attached to the inner wall of the base pipe unit through a plasma spraying process and is subjected to high-temperature sintering treatment. The porosity of the porous slow-release carrier layer is 30-40%. The pre-impregnated cleanup agent is penetrated and stored in the pores of the porous slow-release carrier layer through a vacuum impregnation process. The medicament supplementing unit at least comprises, from top to bottom, a medicament supplementing port, a one-way valve, a medicament storage bin and a penetration channel. The application solves the problems of unstable combination of the carrier and the pipe column, complicated cleanup agent supplementing operation, poor adaptability to harsh well conditions and low filling efficiency in the prior art.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to an integrated tubing string for a slow-release drainage aid and a method for replenishing the drainage aid. Background Technology

[0002] During gas well production, existing drainage technologies primarily rely on two methods to address the issue of fluid accumulation in gas wells: one-time wellhead injection and simple carrier adsorption. While one-time wellhead injection is simple to operate, the drainage agent is rapidly consumed within the tubing as it flows with the gas and fluid, resulting in a short shelf life and requiring frequent re-injection. Simple carrier adsorption, on the other hand, relies heavily on physical adhesion between the carrier and the tubing wall, leading to weak bonding strength and an inability to sustain the drainage agent for extended periods. Furthermore, once the drainage agent is depleted, several kilometers of tubing must be pulled out for refilling, resulting in a single operation exceeding 24 hours and high costs per well. This seriously affects the economics of extraction. On the other hand, for gas wells with high water cut, the amount of liquid accumulated is larger and the fluidity is worse. Existing drainage aids are prone to react with Ca²+ and Mg²+ ions in formation water to form flocculent precipitates. For gas wells with high salinity, the solubility of drainage aids decreases. Both of these situations will cause the drainage aids to lose their drainage function. At the same time, the existing replenishment structure lacks pressure buffering and directional permeation design. During injection, the drainage aid is prone to splashing and being wasted due to a sudden increase in pressure, or the carrier pore filling rate is less than 50% due to uneven permeation path, resulting in a significant reduction in the replenishment effect. Summary of the Invention

[0003] The purpose of this invention is to provide an integrated tubing string for slow-release drainage aid and a method for replenishing the drainage aid, which solves the problems of unstable carrier-tubing bonding, cumbersome drainage aid replenishment operation, poor adaptability to harsh well conditions, and low filling efficiency in the prior art.

[0004] The technical solution of the present invention:

[0005] This invention provides an integrated tubular column for a sustained-release drainage aid, comprising a base tube unit, a porous sustained-release carrier layer, a pre-impregnated drainage aid, and a drug replenishment unit, specifically:

[0006] The base tube unit is a hollow tube with open ends. The upper end of the base tube unit has external threads, and the lower end has internal threads. The porous slow-release carrier layer is attached to the inner wall of the base tube unit by plasma spraying and is sintered at high temperature. The porosity of the porous slow-release carrier layer is 30-40%, and the bonding strength between the porous slow-release carrier layer and the inner wall of the base tube unit is not less than 20 MPa. The pre-impregnated drainage aid is permeated and stored in the pores of the porous slow-release carrier layer by vacuum impregnation. The agent replenishment unit is located inside the base tube unit and on the side close to the external threads. The pressure resistance of the agent replenishment unit is not less than 8 MPa. The agent replenishment unit includes at least an agent replenishment port, a one-way valve, an agent storage chamber, and a permeation channel connected sequentially from top to bottom.

[0007] Furthermore, the drug replenishment port is located between the inner and outer walls of the base tube unit, and the drug replenishment port has an internal thread. The drug replenishment port is detachably connected to an external injection device. The one-way valve is embedded inside the drug replenishment port. The drug storage chamber is located between the inner and outer walls of the base tube unit, and the drug storage chamber is a hollow annular channel coaxial with the base tube unit. The permeation channel is a cylindrical channel, and multiple permeation channels are evenly spaced and connected in a circular array at the bottom of the drug storage chamber. The outlet of the permeation channel is connected to the porous sustained-release carrier layer.

[0008] Furthermore, the check valve is a ball-type check valve, and its valve core is made of oil-resistant rubber and its valve seat is made of stainless steel. The opening pressure of the check valve is 0.5-1MPa and the closing pressure is 0.1-0.3MPa.

[0009] Furthermore, the medicine replenishment port has a sealing groove, and a high-pressure resistant sealing ring is embedded in the sealing groove, with a pressure tolerance value ≥30MPa.

[0010] Furthermore, the porous sustained-release carrier layer is made of porous ceramic, and the thickness of the porous sustained-release carrier layer is 2-3 mm, the pore size is 50-100 μm and they are interconnected; the width of the drug storage chamber is 6-10 mm; the diameter of the permeation channel is 1-3 mm; the thickness between the drug storage chamber and the inner wall of the base tube unit is 5-8 mm greater than the thickness between the drug storage chamber and the outer wall of the base tube unit.

[0011] Furthermore, the pre-impregnated drainage aid is a liquid drainage aid, and the impregnation time of the pre-impregnated drainage aid is 4-6 hours; the release cycle of the pre-impregnated drainage aid is adjusted by the porosity or thickness of the porous slow-release carrier layer, with an adjustment range of 3-6 months, and the daily average release amount fluctuates by no more than 10% during the release process.

[0012] Furthermore, when the water cut of the target gas well is greater than 20%, the porosity of the porous slow-release carrier layer is 35-40%, and 0.5-1% of organic amine salt anti-salt component is added to the pre-impregnated drainage aid.

[0013] Another aspect of the present invention provides a method for supplementing a slow-release effusion aid, comprising the following steps:

[0014] Step 1: When the integrated tubing for the drainage aid has been running in the well for 3 months, or when the surface tension of the fluid inside the tubing is measured at the wellhead and found to be >32mN / m, replenishment should be initiated.

[0015] Step 2: Close the production valve, release the residual pressure in the base tube unit to 0MPa, and thread the external injection pump connector to the drug replenishment port and seal it.

[0016] Step 3: Start the injection pump and inject the excretion aid at a pressure of 5-8 MPa to open the one-way valve and enter the drug storage chamber. Then, it enters the porous sustained-release carrier layer through the permeation channel.

[0017] Step 4: Maintain a pressure of 5-8 MPa during injection until the injection pump flow rate drops below 0.5 L / h and the pressure stabilizes, indicating that the filling is complete;

[0018] Step 5: Stop the injection, depressurize to 0.1-0.3 MPa to close the check valve, disassemble the injection pump and open the production valve.

[0019] Furthermore, the external injection pump is a conventional high-pressure injection pump at the wellhead, with a rated output pressure ≥15MPa, a flow rate adjustment range of 0-50L / h, and a pressure sensor installed at the pump outlet.

[0020] Furthermore, when the water cut of the target gas well is greater than 20%, before injecting the pre-impregnation drainage aid, an organic amine salt anti-salt component is first added, then stirred evenly and filtered through a 5μm filter membrane, and finally heated to 45-50℃.

[0021] Based on the above technical features, the beneficial effects of the present invention are as follows:

[0022] (1) The slow-release catalytic converter integrated column provided by the present invention can avoid the limitation of physical adhesion between the traditional carrier and the column by setting a porous slow-release carrier layer and a drug replenishment unit. The carrier layer and the inner wall of the column are bonded with high strength by plasma spraying and high temperature sintering process, and the bonding strength is not less than 20MPa. It can maintain structural integrity under long-term gas-liquid scouring and avoid catalytic converter failure caused by carrier detachment.

[0023] (2) The slow-release drainage aid integrated tubing provided by the present invention can form a pressure buffer and directional permeation through the set drug storage chamber and permeation channel. The injected drainage aid is first temporarily stored in the annular storage chamber to equalize the pressure, and then accurately injected into the carrier layer pores through the directional permeation channel. This solves the problem of drainage aid splashing and waste caused by sudden pressure rise in traditional replenishment methods and the problem of low carrier pore filling rate caused by uneven permeation path. It effectively improves replenishment efficiency and filling uniformity.

[0024] (3) The slow-release facilitator integrated tubing provided by the present invention, by setting a ball-shaped one-way valve with opening pressure and closing pressure parameter limits in the agent replenishment port, and in conjunction with the wellhead high-pressure injection pump, can realize the convenient operation of replenishing the facilitator by simply docking at the wellhead. The entire process does not require pulling out the tubing, and the single operation time does not exceed one hour, thereby greatly shortening the operation time and reducing the operation cost. Attached Figure Description

[0025] Figure 1 A schematic diagram of the device is provided for this invention;

[0026] Figure 2 This is a flowchart illustrating the method of the present invention.

[0027] In the diagram: 1. Base tube unit; 101. External thread; 102. Internal thread; 2. Porous slow-release carrier layer; 3. Drug replenishment unit; 301. Drug replenishment port; 302. One-way valve; 303. Drug storage chamber; 304. Permeation channel. Detailed Implementation

[0028] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] To better understand this invention, it should be noted that efficient gas well production has always been a core concern in the oil and gas field. During gas well production, especially in mid-to-late stage gas wells, as formation energy continues to decline, the flow velocity of the gas-liquid mixture inside the tubing decreases significantly. Due to its high surface tension, the liquid is easily trapped on the inner wall of the tubing, resulting in liquid accumulation. The presence of liquid accumulation not only significantly increases the flow resistance of the gas well, leading to a continuous increase in bottom hole back pressure and a sustained decline in gas production, but in severe cases, it can even form a liquid lock at the bottom of the well, forcing the gas well to shut down.

[0031] Example 1

[0032] Please refer to Figure 1 The present invention provides a slow-release drainage aid integrated tubing, which relates to the field of oil and gas field development technology. The device includes a base tubing unit 1, a porous slow-release carrier layer 2, a pre-impregnated drainage aid, and a reagent replenishment unit 3.

[0033] It should be noted that the slow-release auxiliary pumping unit provided in this embodiment has a hollow tube unit 1 with open ends. The upper end of the outer tube unit 1 has an external thread 101, and the lower end has an internal thread 102. Adjacent tube segments are connected and assembled using API standard tubing threads, which enables rapid splicing of multiple tube segments with reliable connection, good sealing, and convenient disassembly and assembly, facilitating on-site transportation and well operation. The inner wall of the tube unit 1 needs to be pretreated before the porous slow-release carrier layer 2 is prepared. It is treated with a sandblasting process using brown corundum with a particle size of 0.5 to 1 mm to achieve a surface roughness of 5 to 10 μm, thereby increasing the specific surface area of ​​the inner wall and providing good mechanical bonding conditions for the subsequent adhesion of the carrier layer. After sandblasting, it is ultrasonically cleaned with acetone for 15 minutes to remove oil and rust from the inner wall surface, ensuring that the inner wall of the tube unit 1 is clean and dry, creating favorable conditions for the subsequent plasma spraying process.

[0034] In some embodiments, the base pipe unit 1 is made of stainless steel or carbon steel, preferably N80 stainless steel seamless steel pipe, which has excellent corrosion resistance and can adapt to the sulfur-containing corrosion conditions in downhole wells. Specifically, the base pipe unit 1 has the specifications of Φ89mm×9.19mm and an inner diameter of 70.62mm. The total length is designed to be 50 to 100m according to the actual well depth, and preferably it is processed into 5 sections, each section being 10 to 20m long.

[0035] It should be noted that the porous slow-release carrier layer 2 provided in this embodiment is made of porous ceramic. The porous slow-release carrier layer 2 is attached to the inner wall of the base tube unit 1 via plasma spraying and then subjected to high-temperature sintering to form a uniform porous ceramic coating. The porosity of the porous slow-release carrier layer 2 is 30-40%, and the bonding strength between the porous slow-release carrier layer 2 and the inner wall of the base tube unit 1 is not less than 20 MPa. Specifically, the porous slow-release carrier layer 2 has a thickness of 2-3 mm, a pore size of 50-100 μm, and is interconnected. Preferably, it contains 95% alumina ceramic powder with a particle size of 50-100 μm. In detail, the process was carried out using a Metco 4MB plasma spraying equipment. The plasma arc voltage was set to 65V, the current to 400A, and the spraying distance to 150mm. During the spraying process, the ceramic powder was heated to a molten state by the plasma arc and sprayed at high speed onto the inner wall of the base tube unit 1, forming a uniform coating with a thickness of 2.5mm and an error of ±0.2mm. After the spraying was completed, the base tube unit 1 was placed in an SK2-12-16 box sintering furnace, heated to 1100℃ and held for 2 hours, and then cooled to room temperature with the furnace. After testing, the porosity of the carrier layer after sintering was 35% (mercury intrusion porosimetry test), and the bonding strength with the inner wall of the base tube unit 1 reached 22MPa. Tensile peel test results showed that the bonding strength was not less than 20MPa, and the pores were distributed in an interconnected manner. In this embodiment, the ceramic coating is bonded to the inner wall of the base tube unit 1 by sintering, which can overcome the limitation of the traditional carrier and tube being only physically attached. This ensures that the carrier layer maintains its structural integrity under long-term gas-liquid scouring and will not fall off. The pores of the sintered carrier layer are interconnected, which is beneficial for the storage and release of the drainage aid.

[0036] In some embodiments, the porous sustained-release carrier layer 2 is made of alumina ceramic or silicon carbide ceramic, which can provide sufficient storage space and release channels for the pre-impregnated drainage aid.

[0037] It should be noted that the slow-release drainage aid integrated tubing provided in this embodiment has a pre-impregnated drainage aid that is permeated and stored in the pores of the porous slow-release carrier layer 2 through a vacuum impregnation process. The pre-impregnated drainage aid is preferably a fluorocarbon or polyether liquid drainage aid, which has good compatibility with oil and gas well formation fluids and has no risk of precipitation.

[0038] It should be noted that in the slow-release effluent aid integrated tubing provided in this embodiment, the agent replenishment unit 3 is located inside the base tube unit 1 and on the side closest to the external thread 101; the agent replenishment unit 3 includes at least an agent replenishment port 301, a one-way valve 302, an agent storage chamber 303, and a permeation channel 304 connected sequentially from top to bottom. Specifically:

[0039] The reagent replenishment port 301 is located between the inner and outer walls of the base pipe unit 1, meaning the reagent storage chamber 303 is also located between the inner and outer walls of the base pipe unit 1. The reagent storage chamber 303 is a hollow annular channel coaxial with the base pipe unit 1. The reagent replenishment port 301 is detachably connected to external injection equipment. The reagent replenishment port 301 is integrally formed on the upper part of the base pipe unit 1 and has an internal thread 102 of API 2-7 / 8 REG specification, compatible with existing wellhead injection pump connectors. The reagent replenishment port 301 possesses sufficient mechanical strength to withstand the high-pressure loads during injection.

[0040] Preferably, the agent replenishment port 301 has a sealing groove, and a high-pressure resistant sealing ring is embedded in the sealing groove, with a pressure tolerance value ≥30MPa. Preferably, the sealing groove is 5mm wide and 3mm deep, and the fluororubber sealing ring is Φ80mm×5mm with a pressure tolerance value of 35MPa.

[0041] The one-way valve 302 controls the unidirectional flow of the agent and prevents backflow of high-pressure fluid downhole. Specifically, the one-way valve 302 is a ball-shaped one-way valve embedded inside the agent replenishment port 301. The ball-shaped valve core is sensitive to opening and reliable to sealing. It can open quickly when the high-pressure pumping agent is injected and close quickly when the pressure is released to prevent high-pressure gas from backflowing into the injection pipeline. The valve core of the ball-shaped one-way valve 302 is made of oil-resistant rubber and the valve seat is made of stainless steel. The opening pressure of the one-way valve 302 is 0.5-1MPa and the closing pressure is 0.1-0.3MPa. The Shore A hardness of the valve core is 70±5, and the valve seat is made of 316L stainless steel with a machining precision of IT6 and is calibrated by a pressure testing machine. In some embodiments, the opening pressure of the ball-shaped one-way valve 302 is 0.8MPa and the closing pressure is 0.2MPa. During assembly, the one-way valve 302 is fixed inside the drug replenishment port 301 by thread, and the tightening torque is controlled at 25 N·m to ensure that the coaxiality between the valve core and the valve seat is ≤0.1 mm, without any jamming, and to ensure smooth subsequent switching action.

[0042] The reagent storage chamber 303 is located between the inner and outer walls of the base tube unit 1, and is a hollow annular channel coaxial with the base tube unit 1. Specifically, the width of the reagent storage chamber 303 is 6-10 mm, and the diameter of the permeation channel 304 is 1-3 mm. When the external injection pump injects the drainage aid at high pressure, the drainage aid first enters the reagent storage chamber 303 for temporary storage and pressure equalization, and then slowly permeates through the permeation channel 304 to the porous slow-release carrier layer 2 below. This avoids the problem of drainage aid splashing and waste caused by the direct impact of high-pressure reagents on the carrier layer in traditional replenishment methods, and plays an effective pressure buffering role. The annular structure of the reagent storage chamber 303 increases the storage space of the drainage aid, allowing the injected drainage aid to stay in it briefly, resulting in a more uniform pressure distribution and providing favorable conditions for directional permeation.

[0043] Preferably, the thickness between the drug storage chamber 303 and the inner wall of the base tube unit 1 is 5-8 mm greater than the thickness between the drug storage chamber 303 and the outer wall of the base tube unit 1, thereby forming a thickened structure to accommodate the drug replenishment unit 3.

[0044] The permeation channel 304 is a cylindrical channel. Multiple permeation channels 304 are evenly spaced and connected in a circular array at the bottom of the drug storage chamber 303. The outlet of the permeation channel 304 is connected to the porous sustained-release carrier layer 2. Specifically, the inlet end of the permeation channel 304 is connected to the lower end of the drug storage chamber 303, and the outlet end is connected to the porous sustained-release carrier layer 2. The permeation channel 304 causes the drainage aid to experience a certain flow resistance when passing through, further realizing pressure attenuation and uniform flow distribution. After passing through the permeation channel 304, the drainage aid enters the pores of the porous sustained-release carrier layer 2 with a smaller flow rate and lower pressure, achieving directional permeation and filling.

[0045] Optionally, the number of permeation channels 304 is set according to the diameter of the tubing and the replenishment efficiency requirements. Preferably, 3-5 channels are set and evenly distributed along the ring, so that the drainage aid can be evenly filled into each area of ​​the carrier layer.

[0046] Optionally, the pipe wall of the base pipe unit 1 corresponding to the reagent storage chamber 303 and the permeation channel 304 area is locally thickened or has an embedded stress dispersion reinforcement ring, thereby compensating for the circumferential stress concentration caused by the opening of cavities and array channels.

[0047] Optionally, the junction between the outlet end of the permeation channel and the porous slow-release carrier layer 2 is a smooth transition chamfer, which can reduce scouring stress and ensure that the safety factor of this area is not less than 2.0 under the coupled conditions of injection pressure and downhole external extrusion pressure.

[0048] It should be noted that the pressure resistance of the reagent replenishment unit 3 is not less than 8 MPa. When the external injection pump injects the drainage aid at a pressure of 5-8 MPa, the one-way valve 302 can be opened, and the drainage aid can smoothly penetrate into the pores of the porous slow-release carrier layer 2. When filling is completed, the injection pressure is stably maintained at 5-8 MPa. The reagent replenishment unit 3 adopts a wellhead docking replenishment method, which can complete the drainage aid replenishment without pulling out the downhole integrated tubing. The single operation time does not exceed 1 hour, which can significantly shorten the operation time and reduce the operation cost.

[0049] Furthermore, when the water cut of the target gas well is greater than 20%, the porosity of the porous slow-release carrier layer 2 is 35-40%, which enables the drainage aid to maintain good solubility in high-water-cut, high-salinity formation water environments, avoiding precipitation and ensuring the continued effectiveness of the drainage aid function under harsh well conditions. Adding 0.5-1% of organic amine salt salt-resistant components to the pre-impregnated drainage aid can improve its solubility in high-salinity formation water and prevent it from reacting with Ca in the formation water. 2+ Mg 2+ The plasma reaction generates flocculent precipitate, which ensures that the drainage assistance function remains effective under harsh well conditions with high water content and high mineralization.

[0050] Furthermore, the pre-impregnated drainage aid is a liquid drainage aid, with an impregnation time of 4-6 hours and a filling rate of not less than 90%. The release cycle of the pre-impregnated drainage aid is adjusted by the porosity or thickness of the porous slow-release carrier layer 2, with an adjustment range of 3-6 months. Moreover, the daily average release volume fluctuation during the release process does not exceed 10%, which can ensure that the release rhythm is consistent with the drainage needs in actual gas well production.

[0051] Example 2

[0052] Please refer to Figure 2 Based on Example 1, the present invention also provides a method for supplementing a sustained-release effusion aid, comprising the following steps:

[0053] Step 1: Determine the timing of replenishment: When the integrated tubing for the drainage aid has been in operation for 3 months, or when the surface tension of the fluid inside the tubing is greater than 32 mN / m according to wellhead sampling, it indicates that the pre-impregnated drainage aid in the porous slow-release carrier layer 2 has been basically released, and replenishment should be initiated. Surface tension can be detected by wellhead sampling and using a surface tension meter. When the detected value exceeds the threshold of 32 mN / m, it indicates that the concentration of the drainage aid has decreased to a level that is insufficient to maintain a good drainage effect, and replenishment should be carried out in a timely manner.

[0054] Step 2, Wellhead Pretreatment: Close the production valve, stop the gas well production, release the residual pressure in the base pipe unit 1 to 0MPa to ensure the safety of the injection operation, connect the external injection pump connector to the chemical replenishment port 301 thread and seal it; the external injection pump is a conventional high-pressure injection pump at the wellhead, with a rated output pressure ≥15MPa, a flow rate adjustment range of 0-50L / h and a pressure sensor at the pump outlet;

[0055] Step 3, Injecting the drainage aid: Start the injection pump and inject the drainage aid at a pressure of 5-8 MPa, so that it opens the one-way valve 302 and enters the drug storage chamber 303. Then, it enters the porous sustained-release carrier layer 2 through the permeation channel 304.

[0056] Step 4, Permeation and Filling: Maintain a pressure of 5-8 MPa during injection until the injection pump flow rate drops below 0.5 L / h and the pressure stabilizes, indicating that the filling is complete;

[0057] Step 5, Resume Production: Stop injection, depressurize to 0.1-0.3 MPa to close check valve 302, disassemble injection pump and open production valve.

[0058] In some implementations, the downhole flow aid replenishment process is as follows:

[0059] First, the target gas well has a depth of 2500m and a water cut of 22% (i.e., a high water cut gas well). The preliminary preparation stage took 5 minutes. Specifically, the tubing had been in the well for 5 months and the drainage agent was almost exhausted. When connecting the equipment, the suction end of the conventional injection pump model 3NB-1.2 / 10-15 with a maximum output pressure of 15MPa was connected to the 500L storage tank storing FC-102 drainage agent. The discharge end was connected to the agent replenishment port 301 of the tubing through an API 2-7 / 8 REG external thread 101 connector. The tightening torque was controlled at 30N·m to ensure that the compression of the sealing ring in the sealing groove reached 20%. The absence of bubbles was confirmed by soapy water testing to confirm no leakage.

[0060] Secondly, the opening of the one-way valve 302 and the injection of the drainage aid take 15 minutes. Specifically, after starting the injection pump, the pressure is slowly increased. When the pressure reaches 0.8MPa, the one-way valve 302 opens and the pressure is kept stable. Then, the pressure is increased to 6MPa. The injection flow rate is controlled at 50L / h and the injection continues for 30 minutes. The total injection volume is 25L. Based on the total pore volume of the carrier layer of a 100m tubing, which is about 53L, the filling rate is about 47%, leaving space for subsequent pressure holding and permeation.

[0061] Next, the pressure holding and permeation stage lasted 30 minutes. Specifically, the injection pump pressure was kept constant at 6 MPa. The flow rate was observed through the flow meter: the flow rate gradually decreased to 0.5 L / h in the first 10 minutes and stabilized below 0.1 L / h in the next 20 minutes. It was determined that the pores of the porous sustained-release carrier layer 2 were filled with a filling rate of ≥90%.

[0062] Next, the pump shutdown and check valve 302 closure phase took 5 minutes. After shutting down the injection pump, the pressure relief valve was slowly opened to reduce the pipeline pressure to 0.2 MPa, the closing pressure of check valve 302. After observing that the pressure did not rise, the pressure relief valve was closed. The injection pump connector was disassembled, and the agent replenishment port 301 was checked for oil and gas leaks. The total replenishment operation took 55 minutes, making the single operation time ≤1 hour. The effect verification after replenishment showed that after the gas well resumed production, the surface tension of the liquid in the pipe dropped to 27 mN / m, the viscosity decreased by 25%, the gas-liquid flow was stable as a circulating flow without slugging, and the liquid carrying efficiency increased by 20% compared with before replenishment, fully meeting the drainage assistance requirements.

[0063] Furthermore, when the water cut of the target gas well is greater than 20%, before injecting the pre-impregnation drainage aid, an organic amine salt anti-salt component is first added, then stirred evenly and filtered through a 5μm filter membrane, and finally heated to 45-50℃.

[0064] In some implementations, the target gas well has a salinity of 20 × 10³ mg / L and a water cut of 28% (water cut > 20%, salinity > 10 × 10³ mg / L, i.e., a high salinity and high water cut well condition). The operation process is as follows:

[0065] First, during the tubing preparation stage, the sintering temperature of the porous slow-release carrier layer 2 is reduced to 1050℃, thereby increasing the porosity of the carrier layer to 38% and increasing the storage capacity of the drainage aid to meet the consumption requirements of wells with high water cut.

[0066] Secondly, during the preparation of the pre-impregnation drainage aid, 0.8% of the organic amine salt anti-salt component DMEA was added to the FC-102 drainage aid. After testing, the modified drainage aid showed no precipitation after standing for 72 hours in formation water with a mineralization of 20×10³mg / L, indicating a significant improvement in solubility.

[0067] Next, during the replenishment of the drainage aid, the drainage aid containing salt-resistant components was heated to 60°C to further reduce its viscosity, adapting to the permeation requirements under high water cut conditions. The pressure-holding permeation time was extended to 40 minutes to ensure that the drainage aid fully filled the pores. Experimental testing showed that after replenishment, the drainage aid filling rate of the porous slow-release carrier layer 2 reached 91%, and the slow-release period was extended to 160 days, approximately 5.3 months. During gas well production, no sedimentation occurred in the pipe, and the liquid carrying efficiency was steadily increased by 18%, fully adapting to the harsh well conditions of high salinity and high water cut.

[0068] It should be noted that during normal production of oil and gas wells, the gas-liquid mixture inside the pipe washes over the porous slow-release carrier layer 2. Under the washing action of the gas-liquid mixture, the drainage aid pre-impregnated in the pores of the carrier layer gradually seeps out and mixes with the fluid inside the pipe. The seeping drainage aid acts on the fluid inside the pipe, which can reduce the surface tension of the liquid to 25-30 mN / m and reduce the viscosity by 20%-30%. This can reduce the amount of liquid retained on the inner wall of the base pipe unit 1 and inhibit bubble aggregation, stabilizing the mist or circulation state of the gas-liquid mixture. The stable mist or circulation state is conducive to the smooth transport of the gas-liquid mixture from the bottom of the well to the wellhead, which can avoid the adhesion and accumulation of liquid on the inner wall of the tubing string and maintain the stable production of the gas well.

[0069] It should be noted that the remaining structures are existing technologies and will not be discussed further here.

[0070] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0071] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A slow-release drainage aid integrated tubing, comprising a base tube unit (1), a porous slow-release carrier layer (2), a pre-impregnated drainage aid, and a reagent replenishment unit (3), characterized in that: The base tube unit (1) is a hollow tube with open ends. The upper end of the base tube unit (1) has an external thread (101) and the lower end has an internal thread (102). The porous slow-release carrier layer (2) is attached to the inner wall of the base tube unit (1) by plasma spraying process and is subjected to high temperature sintering treatment. The porosity of the porous slow-release carrier layer (2) is 30-40%, and the bonding strength between the porous slow-release carrier layer (2) and the inner wall of the base tube unit (1) is not less than 20MPa. The pre-impregnated drainage aid is permeated and stored in the pores of the porous slow-release carrier layer (2) through a vacuum impregnation process; The agent replenishment unit (3) is located inside the base tube unit (1) and on the side close to the external thread (101). The pressure resistance of the agent replenishment unit (3) is not less than 8 MPa. The agent replenishment unit (3) includes at least an agent replenishment port (301), a one-way valve (302), an agent storage chamber (303), and a permeation channel (304) connected sequentially from top to bottom.

2. The integrated tubing for the drainage aid according to claim 1, characterized in that, The drug replenishment port (301) is located between the inner and outer walls of the base tube unit (1), and the drug replenishment port (301) has an internal thread. The drug replenishment port (301) is detachably connected to an external injection device. The one-way valve (302) is embedded inside the drug replenishment port (301). The drug storage chamber (303) is located between the inner and outer walls of the base tube unit (1), and the drug storage chamber (303) is a hollow annular channel coaxial with the base tube unit (1). The permeation channel (304) is a cylindrical channel. Multiple permeation channels (304) are evenly spaced and connected in a circular array at the bottom of the drug storage chamber (303). The outlet of the permeation channel (304) is connected to the porous sustained-release carrier layer (2).

3. The integrated tubing for the drainage aid according to claim 2, characterized in that, The one-way valve (302) is a ball-type one-way valve, and its valve core is made of oil-resistant rubber and its valve seat is made of stainless steel. The opening pressure of the one-way valve (302) is 0.5-1MPa and the closing pressure is 0.1-0.3MPa.

4. The integrated tubing for the drainage aid according to claim 2, characterized in that, The drug replenishment port (301) has a sealing groove, and a high-pressure resistant sealing ring is embedded in the sealing groove, with a pressure tolerance value ≥30MPa.

5. The integrated tubing for the drainage aid according to claim 2, characterized in that, The porous sustained-release carrier layer (2) is made of porous ceramic. The porous sustained-release carrier layer (2) has a thickness of 2-3 mm and a pore size of 50-100 μm, which are distributed in an interconnected manner. The width of the drug storage chamber (303) is 6-10 mm. The diameter of the permeation channel (304) is 1-3 mm. The thickness between the drug storage chamber (303) and the inner wall of the base tube unit (1) is 5-8 mm greater than the thickness between the drug storage chamber (303) and the outer wall of the base tube unit (1).

6. The integrated tubing for the drainage aid according to claim 2, characterized in that, The pre-impregnated drainage aid is a liquid drainage aid, and the impregnation time of the pre-impregnated drainage aid is 4-6 hours; the release cycle of the pre-impregnated drainage aid is adjusted by the porosity or thickness of the porous slow-release carrier layer, with an adjustment range of 3-6 months, and the daily average release amount fluctuates by no more than 10% during the release process.

7. The integrated tubing for the drainage aid according to claim 2, characterized in that, When the water cut of the target gas well is greater than 20%, the porosity of the porous slow-release carrier layer (2) is 35-40%, and 0.5-1% of organic amine salt anti-salt component is added to the pre-impregnated drainage aid.

8. A method for supplementing a slow-release effusion aid, characterized in that, Includes the following steps: Step 1: When the integrated tubing for the drainage aid has been running in the well for 3 months, or when the surface tension of the fluid inside the tubing is measured at the wellhead and found to be >32mN / m, replenishment should be initiated. Step 2: Close the production valve, release the residual pressure in the base tube unit (1) to 0MPa, and thread the external injection pump connector to the drug replenishment port (301) and seal it. Step 3: Start the injection pump and inject the excretion aid at a pressure of 5-8 MPa, so that it opens the one-way valve (302) and enters the drug storage chamber (303). Then, it enters the porous sustained-release carrier layer (2) through the permeation channel (304). Step 4: Maintain a pressure of 5-8 MPa during injection until the injection pump flow rate drops below 0.5 L / h and the pressure stabilizes, indicating that the filling is complete; Step 5: Stop the injection, depressurize to 0.1-0.3MPa to close the one-way valve (302), disassemble the injection pump and open the production valve.

9. The method for supplementing the effusion aid according to claim 8, characterized in that, The external injection pump is a conventional high-pressure injection pump at the wellhead, with a rated output pressure ≥15MPa, a flow rate adjustment range of 0-50L / h, and a pressure sensor at the pump outlet.

10. The method for supplementing the effusion aid according to claim 8, characterized in that, When the water cut of the target gas well is greater than 20%, before injecting the pre-impregnation drainage aid, first add the organic amine salt anti-salt component, then stir evenly and filter through a 5μm filter membrane, and finally heat to 45-50℃.

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