Multi-layer and casing leakage heavy oil well steam injection pipe column and huff and puff yield increasing method

Abstract

The invention relates to the technical field of heavy oil field oil extraction processes, in particular to a multi-layer and casing leakage heavy oil well steam injection tubular column and a huff and puff yield increasing method. A steam injection huff-puff process technology is implemented on a gasoline injection layer of a multi-layer heavy oil well and a gasoline injection layer of a casing leakage heavy oil well by designing a multi-layer and casing leakage heavy oil well steam injection tubular column and applying the multi-layer and casing leakage heavy oil well steam injection tubular column. The method is applied to oil field heavy oil well exploitation, huff and puff steam injection is achieved through clamping and sealing of the high-temperature packer, the input cost is low, the potential layer reserve utilization degree can be greatly improved, normal steam injection of a multi-layer and casing leakage heavy oil well is guaranteed, the contradiction between layers and the plane contradiction of the heavy oil well are solved, the crude oil yield is increased, and the crude oil recovery rate of a heavy oil block is increased.

Description

Technical Field

[0001] The invention relates to the technical field of heavy oil field oil production technology, in particular to a multi-layer and casing leakage heavy oil well steam injection pipe string and a throughput increase method. Background Art

[0002] At present, in the process of oil field development, the existing technology can only adopt the method of plugging the upper oil layer and injecting steam in general for oil wells with two oil layers. During the steam injection process, due to high temperature and high pressure, the plugging layer is easily squeezed open, thus losing the meaning of steam injection, resulting in poor effect and waste of cost; for oil wells with more than two layers, if the lower oil layer is produced, the plugging process cannot be carried out due to the difference between the layers, and steam injection production cannot be carried out. Therefore, it is necessary to adopt the method of losing the plugging for oil wells with more than two layers to achieve steam injection production.

[0003] In addition, there are more and more casing leakage wells. It is difficult to plug the wells with cement in the upper 200-500m of the wells, or even in the deep 1000m. Due to the poor quality of the insulation pipes used, the high apparent thermal conductivity, and the lack of detection means, it is impossible to judge whether the thermosensitive packer is expanded and sealed. During steam injection, the casing pressure is generally high, and the weak parts of the casing are easily squeezed open to form leaks, resulting in pipe string stuck accidents. If a casing leak is found during the operation, a plugging method is adopted for one leak, but the pressure can only be tested to 6.0MPa, which is too low. If there are two leaks, the plugging operation cannot be performed. The well can no longer be injected with steam for production, and can only be cold-produced, with low liquid volume, poor effect, or shutdown due to multiple leaks. Therefore, it is necessary to adopt the method of losing the seal for the casing leakage wells to achieve steam injection production. Summary of the invention

[0004] In view of the above problems, the present invention provides a steam injection string and a throughput increase method for multi-layer and casing leakage heavy oil wells. The shortcomings of the prior art are overcome, the steam injection problem of multi-layer heavy oil wells and casing leakage in oil fields is solved, the crude oil production is increased, and the recovery rate of heavy oil blocks is improved.

[0005] The technical solution of the present invention is achieved by the following methods: The multi-layer and casing leakage heavy oil well steam injection pipe string of the present invention comprises: casing, insulation pipe, compensator, backwash well valve, close plug, Y445 high temperature packer, oil pipe, sealing layer I, sealing layer II, Y221 high temperature packer, bell mouth, gasoline injection layer, and artificial well bottom. The multi-layer heavy oil well steam injection pipe string is threadedly connected and tightened step by step from bottom to top, and is lowered into the casing to above the artificial well bottom through the operating power equipment. The Y445 high temperature packer is located at the upper part of the sealing layer I, and the Y221 high temperature packer is located at the lower part of the sealing layer II and the upper part of the gasoline injection layer.

[0006] The above-mentioned method for increasing production by using a steam injection string in a multi-layer and casing leakage heavy oil well is as follows: Step 1. Preparation: transport the operation and related auxiliary equipment to the well site, complete the preparatory work before the operation, meet the site standards specified by the oil field, and conduct the start-up acceptance; Step 2. Start the operation: remove the wellhead device of the pumping well, install the wellhead blowout preventer, pull out all the rod and tube pumps in the well, and fish out all the sand control tools in the well; Step 3. Flushing and dredging the sand flushing pipe string: Connect the bottom of the sand flushing pipe string to the well gauge, lower it into the casing (1), connect the sand flushing pipe string to the pump truck through the square drill rod, faucet, and hose, use the pump truck to flush the casing (1) to the designed position, circulate and rinse the casing (1), and scrape the inner wall of the casing (1) clean through the well gauge; Step 4. ① During the steam injection construction of multi-layer heavy oil well steam injection pipe string: test the casing pressure, lower the Y211 high temperature packer to 5-10m above the gasoline injection layer, test the casing pressure to 15MPa, stabilize the pressure for 30min, and the pressure drop is not more than 0.5MPa, which is qualified, and all the pipe strings are pulled out; lower the sealing pipe string, and lower the bell mouth, Y221 high temperature packer, oil pipe, and Y445 high temperature packer to the designed position in sequence, and then use a density of 1.01t / m 3 Oilfield produced water 50m 3 Flushing the well, flushing the wellbore clean; ② During the steam injection construction of the steam injection string in the casing leakage heavy oil well: test the casing pressure, re-verify the leakage point, and lower the oil pipe and Y211 packer string to the leakage point to set the seal, squeeze out the sewage, test the casing pressure at 15MPa, stabilize the pressure for 30min, and the pressure drop is not more than 0.5MPa to be qualified; pull up the oil pipe and Y211 packer string to unseal, and then lower the Y445 high-temperature packer to the leakage point to squeeze the pressure test at 15MPa, stabilize the pressure for 30min, and the pressure drop is not more than 0.5MPa to be qualified, lower the sealing string, lower the bell mouth and Y445 high-temperature packer to the designed position, and use a density of 1.01t / m 3 Oilfield produced water 50m 3 Flushing the well, flushing the wellbore clean; Step 5. Rotate and set the Y221 high temperature packer 10. The operation method is as follows: ① Lift the pipe string to adjust the setting and pressurizing height. The lifting height of the pipe string is determined according to the well depth; ② Slowly lower and rotate the pipe string, and observe the weight gauge. If the weight gauge drops, it indicates that the Y221 high-temperature packer begins to set; ③ Pressurize to 60-80KN to make it fully sealed, continue to rotate after setting, and remove the pipe string after throwing it away; Step 6. Throw a φ35mm steel ball to pressurize the Y445 high-temperature packer. After the ball is sunk for 20 minutes, lift the pipe string 30cm and pressurize to 4.0MPa, 6.0MPa, 8.0MPa, 10.0MPa, and 12.0MPa respectively. Keep the pressure steady for 5 minutes each time, lower the pipe string, check the seal and continue to pressurize to 0MPa. The channel is opened, indicating that the seal is lost successfully, and the lost pipe string is pulled out; Step 7. Magnetic positioning detection: Use the detection instrument to detect the positioning of the running tools to ensure that each tool is run to the designated position and that each packer avoids the position of the casing coupling; Step 8. Lower the insulation pipe: lower the close-fitting plug, backwash well valve, insulation pipe and compensator through the pipe string; Step 9. Sealing pressure test: Use a pump truck to test the formation. After the pressure is raised, open the casing gate and observe the pressure gauge on the casing gate. If there is no pressure display, it means that the plug is inserted into the reserved cavity on the upper part of the Y445 high-temperature packer and the seal is intact. Step 10. Squeeze out oil displacement agent and inject steam: According to the steam injection process design, squeeze in the oil displacement agent: well washing fluid = 1:10 ratio liquid through the wellhead, pass through the insulation pipe to the gasoline injection layer, connect the wellhead to the steam injection boiler through the pipeline and start steam injection.

[0007] Technical requirements: 1. High temperature packer must be able to withstand temperatures above 370°C; 2. The apparent thermal conductivity of the steam injection insulation pipe must be above Class D (0.02>λ>0.006W / ℃.m 2 ).

[0008] Principle of steam injection and huff and puff oil production: Due to the high content of colloid and asphaltene in heavy oil, during the production process, as crude oil is continuously produced, the light fraction is further reduced, the colloid and asphaltene increase, the relative density and viscosity of crude oil increase at the same time, the fluidity of crude oil further deteriorates, the liquid supply becomes lower and lower, the water content increases significantly, and production becomes more and more difficult. By injecting steam into the heavy oil layer, the steam decomposes the colloid and asphaltene in the heavy oil, turning large ions into small ions, and increasing the fluidity of crude oil; before steam injection, chemical flooding agents are squeezed in. Chemical flooding agents are surfactants. By reducing the oil-water interfacial tension, the heavy oil in the formation is transformed from an oil-in-water emulsified state to an emulsified state with water as the external phase, which further significantly reduces the viscosity of the heavy oil. The viscosity reducer component can also be adsorbed on the inner wall of the rock pores and the pipe wall to form a hydrophilic film, reducing the flow friction of the heavy oil and further improving the fluidity of the crude oil. Increase the steam sweep range to adjust the wetting ratio of the formation surface, increase the number of capillaries, increase the dispersion of crude oil in water, and further increase the fluidity of crude oil, so as to increase crude oil production and improve crude oil recovery rate.

[0009] Compared with the prior art, the present invention has the following beneficial effects: The present invention is suitable for the exploitation of heavy oil wells in oil fields. It can effectively treat "three lows" (low water content, low recovery degree, and low oil recovery rate) heavy oil wells through high-temperature packer sealing, realize throughput steam injection, have low investment cost, can greatly improve the utilization degree of potential layer reserves, ensure normal steam injection of multi-layer and casing leakage heavy oil wells, solve the interlayer contradiction and plane contradiction of heavy oil wells, increase crude oil production, and improve the crude oil recovery rate of heavy oil blocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings that constitute part of the present invention are used to provide a further understanding of the present invention. The schematic implementation diagrams and descriptions of the present invention are only used to explain the present invention and do not constitute an improper limitation on the present invention.

[0011] Figure 1 - Schematic diagram of a multi-layer steam injection string for heavy oil wells according to the present invention Figure 2 - A schematic diagram of the structure of a steam injection string for a heavy oil well with casing leakage according to the present invention In the figure: 1. casing; 2. insulation pipe; 3. compensator; 4. backwash well valve; 5. close insertion; 6. Y445 high temperature packer; 7. oil pipe; 8. sealing layer I; 9. sealing layer II; 10. Y221 high temperature packer; 11. bell mouth; 12. gasoline injection layer; 13. artificial well bottom; 14. leakage point. DETAILED DESCRIPTION Example

[0012] A multi-layer steam injection pipe string for a heavy oil well of the present invention comprises: a casing 1, an insulation pipe 2, a compensator 3, a backwash well valve 4, a close-fitting 5, a Y445 high-temperature packer 6, an oil pipe 7, a sealing layer I 8, a sealing layer II 9, a Y221 high-temperature packer 10, a bell mouth 11, a gasoline injection layer 12, and an artificial well bottom 13. The multi-layer steam injection pipe string for a heavy oil well comprises a bell mouth 11, a Y221 high-temperature packer 10, an oil pipe 7, a Y445 high-temperature packer 6, a close-fitting 5, a backwash well valve 4, a compensator 3, and an insulation pipe 2 from bottom to top, which are threadedly connected and tightened step by step in sequence, and are lowered into the casing to above the artificial well bottom 13 through an operating power device, the Y445 high-temperature packer 6 is located at the upper part of the sealing layer I 8, and the Y221 high-temperature packer 10 is located at the lower part of the sealing layer II 9 and the upper part of the gasoline injection layer 12.

[0013] The above-mentioned method for increasing production by using a multi-layer steam injection string in a heavy oil well is as follows: Step 1. Preparation: transport the operation and related auxiliary equipment to the well site, complete the preparatory work before the operation, meet the site standards specified by the oil field, and conduct the start-up acceptance; Step 2. Start the operation: remove the wellhead device of the pumping well, install the wellhead blowout preventer, pull out all the rod and tube pumps in the well, and fish out all the sand control tools in the well; Step 3. Flushing and dredging the sand flushing pipe string: Connect the bottom of the sand flushing pipe string to the well gauge, lower it into the casing (1), connect the sand flushing pipe string to the pump truck through the square drill rod, faucet, and hose, use the pump truck to flush the casing (1) to the designed position, circulate and rinse the casing (1), and scrape the inner wall of the casing (1) clean through the well gauge; Step 4. Test the pressure of casing 1, lower the Y211 high-temperature packer to 5-10m above the gasoline injection layer 12, test the casing pressure to 15MPa, stabilize the pressure for 30min, and if the pressure drop is no more than 0.5MPa, it is qualified, and all the pipes are pulled out; lower the sealing pipe string, and lower the bell mouth 11, Y221 high-temperature packer 10, oil pipe 7, and Y445 high-temperature packer 6 to the designed position in sequence, and then use a density of 1.01t / m 3 Oilfield produced water 50m 3 Flushing the well, flushing the wellbore clean; Step 5. Rotate and set the Y221 high temperature packer 10. The operation method is as follows: ① Lift the pipe string to adjust the setting and pressurizing height. The lifting height of the pipe string is determined according to the well depth; ② Slowly lower and rotate the pipe string, and observe the weight gauge. If the weight gauge falls back, it indicates that the Y221 high-temperature packer 10 begins to set; ③ Pressurize to 60-80KN to make it fully sealed, continue to rotate after setting, and remove the pipe string after throwing it away; Step 6. Throw 6 φ35mm steel balls into the Y445 high-temperature packer to pressurize and seal it. After the ball is sunk for 20 minutes, lift the pipe string 30cm, pressurize to 4.0MPa, 6.0MPa, 8.0MPa, 10.0MPa, and 12.0MPa respectively, keep the pressure stable for 5 minutes each time, lower the pipe string, check the seal and continue to pressurize to 0MPa. The channel is opened, indicating that the seal is lost successfully, and the lost seal pipe string is pulled out; Step 7. Magnetic positioning detection: Use the detection instrument to detect the positioning of the running tools to ensure that each tool is run to the designated position and that each packer avoids the position of the casing coupling; Step 8. Lower the insulation pipe 2: lower the close-fitting plug 5, the backwash well valve 4, the insulation pipe 2, and the compensator 3 through the pipe string; Step 9. Sealing pressure test: Use a pump truck to test the formation. After the pressure is raised, open the casing gate and observe the pressure gauge on the casing gate. If there is no pressure display, it means that the close-fitting plug 5 is inserted into the reserved cavity on the upper part of the Y445 high-temperature packer 6 and the seal is intact; Step 10. Squeeze oil displacement agent and inject steam: According to the steam injection process design, squeeze the oil displacement agent: well washing fluid = 1:10 ratio of liquid through the wellhead, through the insulation pipe 2 to the gasoline injection layer 12, connect the wellhead with the steam injection boiler through the pipeline and start steam injection.

[0014] Hongliu Oilfield is a heavy oil reservoir with multiple layers. Since the oil well HLKD52-112 was put into production on March 12, 2003, it has successively opened the oil layer Ngs4 3 (perforation section 1263.5-1266m), oil layer Ngs4 5 (perforated well section 1277.5-1283.0m), oil layer Ngx1 (perforated well section 1430.3-1434.0m), oil layer Ngx2 (perforated well section 1440.9-1444.4m), oil layer Ngx4 (perforated well section 1483.5-1485.5m), there are many perforated well sections. Oil layer Ngx4 is the lowest sand body, with a sand thickness of 4.4m and an effective thickness of 4.0m. It was perforated on May 20, 2009. At that time, because there were four oil layers in the upper part, conventional operations such as plugging could not be adopted, and steam injection could not be carried out. Only cold production methods could be adopted. After production, the liquid volume was 5.1t / d, oil was 1.2t / d, water content was 76.5%, and viscosity was 6283mPa.s. In October 2011, due to the difficulty of lifting due to thick oil, other layers were changed to produce, and the cumulative oil production was 432t. In October 2023, under the actual conditions of high water content in other layers, through the analysis of plane and monitoring data, it is believed that the Ngx4 oil layer is rich in residual oil, and it is decided to adopt the above new process to seal the oil layer Ngs4 3 、Ngs4 5 , Ngx1, Ngx2, exploit the oil layer Ngx4, install the Y221 high temperature packer 10 and inject steam. Steam injection will start on November 2, 2023, with a steam injection volume of 1800m 3 , steam injection speed 6.8m 3 / h, boiler pressure is 15.9MPa, casing pressure is 5.2MPa, steam injection boiler temperature is 330℃, the well is shut down for 5 days after steam injection and then blowdown is carried out. The well was opened on November 23, 2023, and oil was seen 8 days after drainage. The peak output is 5.2t / d. At present, the accumulated oil production has reached 854t, and the input-output ratio has reached 1:2.3, which has achieved good results. Example

[0015] The steam injection pipe string for a heavy oil well with casing leakage of the present invention comprises: a casing 1, an insulating pipe 2, a compensator 3, a backwash well valve 4, a close-fitting plug 5, a Y445 high-temperature packer 6, a bell mouth 11, a gasoline injection layer 12, an artificial well bottom 13, and a leakage point 14; the characteristic is that the steam injection pipe string for the heavy oil well with casing leakage of the present invention comprises a bell mouth 11, a Y445 high-temperature packer 6, a close-fitting plug 5, a backwash well valve 4, a compensator 3, and a thermal insulation pipe 2, which are threadedly connected and tightened step by step from bottom to top, and are lowered into the casing 1 to above the artificial well bottom 13 through an operating power device, and the Y445 high-temperature packer 6 is located below the leakage point 14 and above the gasoline injection layer 12.

[0016] The above-mentioned method for increasing production by using a steam injection string in a casing leakage heavy oil well is as follows: Step 1. Preparation: transport the operation and related auxiliary equipment to the well site, complete the preparatory work before the operation, meet the site standards specified by the oil field, and conduct the start-up acceptance; Step 2. Start the operation: remove the wellhead device of the pumping well, install the wellhead blowout preventer, pull out all the rod and tube pumps in the well, and fish out all the sand control tools in the well; Step 3. Flushing and dredging the sand flushing pipe string: Connect the bottom of the sand flushing pipe string to the well gauge, lower it into the casing (1), connect the sand flushing pipe string to the pump truck through the square drill rod, faucet, and hose, use the pump truck to flush the casing (1) to the designed position, circulate and rinse the casing (1), and scrape the inner wall of the casing (1) clean through the well gauge; Step 4. Test the pressure of casing 1 and re-verify the leak point 14: In addition, lower the oil pipe 7 and Y211 packer string to the leak point 14 and set the seal, squeeze out the sewage, test the pressure of casing 1 at 15MPa, stabilize the pressure for 30min, and the pressure drop is not more than 0.5MPa for passing; lift the oil pipe 7 and Y211 packer string to unseal, and then lower the Y445 high-temperature packer 6 to the leak point 14 and squeeze the pressure test at 15MPa, stabilize the pressure for 30min, and the pressure drop is not more than 0.5MPa for passing. If one of the two pressure tests fails, it is necessary to find the leak point 14 again and verify the relevant information; lower the sealing string, lower the bell mouth 11 and Y445 high-temperature packer 6 to the designed position, and use a density of 1.01t / m 3 Oilfield produced water 50m 3 Flushing the well, flushing the wellbore clean; Step 5. Throw 6 φ35mm steel balls to pressurize and seal the Y445 high-temperature packer: After sinking the ball for 20 minutes, lift the pipe string 30cm, pressurize to 4.0MPa, 6.0MPa, 8.0MPa, 10.0MPa, and 12.0MPa respectively, stabilize the pressure for 5 minutes each time, lower the pipe string, check the seal and continue to pressurize to 0MPa. The channel opens, indicating that the seal is successfully lost, and the lost seal pipe string is pulled out; Step 6. Magnetic positioning detection: Use the detection instrument to detect the positioning of the running tools to ensure that each tool is run to the designated position and that each packer avoids the position of the casing coupling; Step 7. Lower the insulation pipe: lower the close-fitting plug 5, the backwash well valve 4, the insulation pipe 2, and the compensator 3 through the pipe string. The insulation pipe string plays the role of protecting the casing; Step 8. Sealing pressure test: Use a pump truck to test the formation. After the pressure is raised, open the casing gate and observe the pressure gauge on the casing gate. If there is no pressure display, it means that the close-fitting plug 5 is inserted into the reserved cavity on the upper part of the Y445 high-temperature packer 6 and the seal is intact; Step 9. Squeeze out the oil displacement agent and inject steam: According to the steam injection process design, squeeze the oil displacement agent: well washing fluid = 1:10 ratio of liquid through the wellhead, pass through the insulation pipe 2 to the gasoline injection layer 12, connect the wellhead with the steam injection boiler through the pipeline and start steam injection.

[0017] Hongliu Oilfield is a heavy oil reservoir. The oil well HLKD5-12 has a production layer NG44, which is located at the edge of the sand body. The oil is thick and the formation energy is insufficient. On September 19, 2020, due to the lack of liquid supply, the casing pressure test found that the casing was leaking at 10.0m. Because it was too shallow, it could not be plugged and had to be closed. In September 2023, the technical solution of the present invention was adopted to operate the oil well HLKD5-12. Steam injection began on October 2, with a steam injection volume of 1600m 3 , steam injection speed 6.8m 3 / h, boiler pressure 15.4MPa, casing pressure 4.8MPa, steam injection boiler temperature 330℃, the well was shut down for 6 days after steam injection and then blown out. The well was opened on October 24, 2023, and normal production resumed on November 5, with liquid volume 34.4t / d, oil volume 3.4t / d, water content 89.2%, and the accumulated oil production has reached 520t.

Claims

1. A multi-layer and casing leakage heavy oil well steam injection string, comprising: Casing (1), insulation pipe (2), compensator (3), backwash well valve (4), close-fitting (5), Y445 high-temperature packer (6), oil pipe (7), sealing layer I (8), sealing layer II (9), Y221 high-temperature packer (10), bell mouth (11), gasoline injection layer (12), artificial well bottom (13); characterized in that: the multi-layer heavy oil well steam injection pipe string is from bottom to top, bell mouth (11), Y221 high-temperature packer (1 0), oil pipe (7), Y445 high temperature packer (6), close-fitting (5), backwash well valve (4), compensator (3), and heat insulation pipe (2) are threadedly connected and tightened step by step, and lowered into the casing to above the artificial well bottom (13) through the operating power equipment. The Y445 high temperature packer (6) is located on the upper part of the sealing layer I (8), and the Y221 high temperature packer (10) is located on the lower part of the sealing layer II (9) and the upper part of the gasoline injection layer (12).

2. The method for increasing production of a steam injection string for a multi-layer and casing leakage heavy oil well according to claim 1 is as follows: Step 1. Preparation: transport the operation and related auxiliary equipment to the well site, complete the preparatory work before the operation, meet the site standards specified by the oil field, and conduct the start-up acceptance; Step 2. Start the operation: remove the wellhead device of the pumping well, install the wellhead blowout preventer, pull out all the rod and tube pumps in the well, and fish out all the sand control tools in the well; Step 3. Flushing and dredging the sand flushing pipe string: Connect the bottom of the sand flushing pipe string to the well gauge, lower it into the casing (1), connect the sand flushing pipe string to the pump truck through the square drill rod, faucet, and hose, use the pump truck to flush the casing (1) to the designed position, circulate and rinse the casing (1), and scrape the inner wall of the casing (1) clean through the well gauge; Step 4. ① During the steam injection construction of the steam injection string in a multi-layer heavy oil well: the casing (1) is pressure tested, the Y211 high temperature packer is lowered to 5-10m above the gasoline injection layer (12) to set the seal, the casing is pressure tested at 15MPa, the pressure is maintained for 30 minutes, and the pressure drop is not greater than 0.5MPa, which is considered acceptable, and all the pipes are pulled out; the sealing string is lowered, and the bell mouth (11), Y221 high temperature packer (10), oil pipe (7), and Y445 high temperature packer (6) are lowered in sequence to the designed position, and then a 1.01t / m 3 Oilfield produced water 50m 3 Flushing the well, flushing the wellbore clean; ② During the steam injection construction of the steam injection string in the casing leakage heavy oil well: the casing (1) is pressure tested, the leakage point (14) is re-verified, and the oil pipe (7) and the Y211 packer string are lowered to the leakage point (14) to set the seal, and the sewage is squeezed back. The casing (1) is pressure tested at 15MPa, and the pressure is maintained for 30 minutes. The pressure drop is not more than 0.5MPa. The oil pipe (7) and the Y211 packer string are unsealed, and the Y445 high-temperature packer (6) is lowered to the leakage point (14) to test the positive pressure at 15MPa. The pressure is maintained for 30 minutes. The pressure drop is not more than 0.5MPa. The seal string is lowered, and the bell mouth (11) and the Y445 high-temperature packer (6) are lowered to the designed position. The density of 1.01t / m 3 Oilfield produced water 50m 3 Positive well washing: flush the wellbore clean; Step 5. Rotate and set the Y221 high temperature packer (10). The operation method is as follows: ① Lift the pipe string to adjust the setting and pressurizing height. The lifting height of the pipe string is determined according to the well depth; ② Slowly lower and rotate the pipe string, and observe the weight gauge. If the weight gauge drops, it indicates that the Y221 high-temperature packer (10) has started to seal. ③ Pressurize to 60-80KN to make it fully sealed, continue to rotate after setting, and remove the pipe string after throwing it away; Step 6. Throw a φ35mm steel ball into the Y445 high-temperature packer (6) to pressurize and seal it. After the ball is sunk for 20 minutes, lift the pipe string 30 cm and pressurize it to 4.0 MPa, 6.0 MPa, 8.0 MPa, 10.0 MPa, and 12.0 MPa respectively. Keep the pressure steady for 5 minutes each time, lower the pipe string, and check if the seal is qualified. Continue to pressurize it to 0 MPa. The channel is opened, indicating that the seal is successfully lost, and the lost pipe string is pulled out; Step 7. Magnetic positioning detection: Use the detection instrument to detect the positioning of the running tools to ensure that each tool is run to the designated position and that each packer avoids the position of the casing coupling; Step 8. Lower the insulation pipe (2): lower the close-fitting plug (5), the backwash well valve (4), the insulation pipe (2), and the compensator (3) through the pipe string; Step 9. Sealing pressure test: Use a pump truck to test the formation. After the pressure is raised, open the casing gate and observe the pressure gauge on the casing gate. If there is no pressure display, it means that the close-fitting plug (5) is inserted into the reserved cavity on the upper part of the Y445 high-temperature packer (6) and the seal is intact; Step 10. Squeeze out the oil displacement agent and inject steam: According to the steam injection process design, squeeze out the oil displacement agent: well washing fluid in a ratio of 1:10 through the wellhead, pass through the insulation pipe (2) to the gasoline injection layer (12), connect the wellhead to the steam injection boiler through the pipeline and start steam injection.

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