Preparation method and use method of novel oil field water injection well unblocking liquid system

Abstract

The invention relates to the technical field of crude oil exploitation of oil field water injection wells, in particular to a preparation method and a use method of a novel oil field water injection well unblocking fluid system, the preparation method comprises the following steps: 1, uniformly stirring and mixing a required amount of organic acid and water to obtain a first mixed solution; 2, adding a required amount of an oil field complexing descaling blocking remover into the first mixed solution, and uniformly stirring and mixing to obtain a second mixed solution; and 3, adding a required amount of corrosion inhibitor, iron ion stabilizer, clay stabilizer and surfactant into the second mixed solution, and uniformly stirring and mixing to obtain the novel oil field water injection well plug removal liquid. The plugging agent is safe and environment-friendly in the links of proportioning, transportation, use and the like, can thoroughly relieve the blockage of the near wellbore area of the oil field water injection well, meets the injection allocation requirement of the water injection well, and also can avoid the problem of secondary pollution to the oil field stratum after acidification plugging removal.

Description

Technical Field

[0001] The invention relates to the technical field of oil field water injection wells for exploiting crude oil, and relates to a preparation method and a use method of a novel oil field water injection well plugging-removing liquid system. Background Art

[0002] At present, most of my country's oil fields are still developed mainly by water injection, and have entered the middle and late stages of water injection development. Due to the swelling of clay minerals in the oil field formations when exposed to water, the incompatibility of the injected water with the oil layer, the damage to the oil field formations caused by various inorganic or organic scales and water quality factors, the underground oil field formations are very easy to be blocked, the water absorption capacity of the oil field formations is continuously reduced, and the water injection pressure is continuously rising, resulting in the formation of a high-pressure area near the water injection well, reducing the effective water injection pressure difference, causing the water injection volume to decrease rapidly.

[0003] The injection pressure of oil field water injection wells directly affects the water injection efficiency of the water injection wells, increases the load on the formation injection system, and increases the energy consumption cost of water injection. At the same time, long-term high-pressure water injection can easily lead to damage to the oil well casing. Long-term under-injection of oil field water injection wells causes stress sensitivity in the oil field reservoir, reduces the sweep coefficient, and leads to a decrease in the recovery rate of low permeability oil fields.

[0004] At present, the main method for unblocking oilfield water injection wells is to use acidizing to remove formation pollution. The commonly used acidizing fluids are hydrochloric acid system and soil acid system. The main problems are incomplete unblocking and a small range of unblocking treatment. At the same time, acid slag produced after acidizing unblocking causes secondary pollution to the oilfield formation. Moreover, the use of strong acid system to unblock oilfield water injection wells has poor safety and environmental protection in the proportioning, transportation and use.

[0005] In summary, there is an urgent need for an oilfield water injection well unblocking fluid that is safe and environmentally friendly in terms of proportioning, transportation and use, can completely unblock the near-well area of ​​the oilfield water injection well, and can also solve the problem of secondary pollution to the oilfield formation after acid unblocking. Summary of the invention

[0006] The present invention provides a preparation method and a use method of a novel oilfield water injection well unblocking fluid system, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of the existing oilfield water injection well unblocking fluid incompletely unblocking the water injection well and serious secondary pollution to the underground formation.

[0007] One of the technical solutions of the present invention is achieved by the following measures: a novel oilfield water injection well plugging removal liquid system, which comprises, by weight percentage, 10% to 15% of organic acid, 5% to 10% of oilfield complex descaling and plugging removal agent, 2% to 5% of corrosion inhibitor, 1% to 3% of iron ion stabilizer, 1% to 2% of clay stabilizer, 1% to 3% of surfactant, and 62% to 80% of water. The novel oilfield water injection well plugging removal liquid system is prepared according to the following steps: a first step, stirring and mixing the required amount of organic acid and water to obtain a first mixed solution; a second step, adding the required amount of oilfield complex descaling and plugging removal agent to the first mixed solution, stirring and mixing to obtain a second mixed solution; a third step, adding the required amount of corrosion inhibitor, iron ion stabilizer, clay stabilizer and surfactant to the second mixed solution, stirring and mixing to obtain a novel oilfield water injection well plugging removal liquid system.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: In the first step, the organic acid is aminosulfonic acid and citric acid, the mass ratio of aminosulfonic acid to citric acid is 3:1, the stirring time of the organic acid and water at room temperature is 25 min to 35 min, and the stirring speed is 30 r / min to 40 r / min.

[0009] In the above second step, the stirring time is 40 min to 50 min at room temperature, and the stirring speed is 30 r / min to 40 r / min.

[0010] In the third step, the stirring time is 10 min to 15 min at room temperature, and the stirring speed is 30 r / min to 40 r / min.

[0011] The second technical solution of the present invention is achieved by the following measures: a preparation method of a novel oilfield water injection well plugging removal liquid system, comprising: The first step is to stir and mix the required amount of organic acid and water to obtain a first mixed solution; The second step is to add a required amount of the oilfield complex descaling and unblocking agent to the first mixed solution, stir and mix evenly to obtain a second mixed solution; The third step is to add the required amount of corrosion inhibitor, iron ion stabilizer, clay stabilizer and surfactant to the second mixed liquid, stir and mix evenly to obtain a new oilfield water injection well plugging removal liquid system.

[0012] The third technical solution of the present invention is achieved by the following measures: a method for using a novel oilfield water injection well plugging removal liquid system, comprising: In the first step, the required amount of pretreatment liquid aromatic hydrocarbons is injected into the well to dissolve most of the organic scale at the bottom of the well and near the wellbore; The second step is to inject water into the well to displace the aromatic hydrocarbons in the pre-treatment liquid in the well to the bottom of the well and the deeper area near the well. After stopping the injection, the well is shut down for the reaction time to dissolve all organic scales at the bottom of the well and the area near the well. The third step is to inject a new oilfield water injection well plugging removal fluid system into the well to remove the partial blockage of the oilfield production layer near the wellbore; The fourth step is to inject water into the well to displace the new oilfield water injection well unblocking fluid system in the well to a deeper level in the oilfield production layer near the wellbore. After stopping the injection, shut down the well for the reaction time required to remove all blockages in the oilfield production layer in the wellhead area and open the well for normal production injection.

[0013] The following is a further optimization and / or improvement of the third technical solution of the above invention: The reaction time of shutting down the well after stopping injection in the above second step is 2 hours to 4 hours or / and; the reaction time of shutting down the well after stopping injection in the fourth step is 48 hours and above, and then normal production injection is carried out.

[0014] In the first step, the aromatic hydrocarbons in the pretreatment liquid are 60% xylene, 35% kerosene and 5% propylene glycol by weight.

[0015] In the first step, the amount of aromatic hydrocarbons in the pretreatment liquid is 1% to 3% by weight of the new oilfield water injection well plugging removal liquid system.

[0016] The amount of aromatic hydrocarbons in the above-mentioned pretreatment liquid is calculated by weight percentage, including: based on a well depth of 1000 meters or less, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be 1% of the new oilfield water injection well deplugging fluid system; based on a well depth between 1000 meters and 2000 meters, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be between 1% and 3% of the new oilfield water injection well deplugging fluid system; when the well depth is 2000 meters or more, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be 3% of the new oilfield water injection well deplugging fluid system.

[0017] The invention is safe and environmentally friendly in the aspects of proportioning, transportation and use, can completely remove the blockage in the near-well area of ​​the oil field water injection well, meet the injection requirements of the water injection well, and avoid secondary pollution of the oil field formation after acidification and blockage removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 It is a dynamic data curve diagram of the water injection well MHD16239 in the present invention.

[0019] Attached Figure 2 It is a dynamic data curve diagram of the water injection well MHD16247 in the present invention. DETAILED DESCRIPTION

[0020] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0021] The present invention will be further described below in conjunction with embodiments: Embodiment 1: The novel oilfield water injection well plugging removal liquid system comprises, by weight percentage, 10% to 15% of organic acid, 5% to 10% of oilfield complex descaling and plugging removal agent, 2% to 5% of corrosion inhibitor, 1% to 3% of iron ion stabilizer, 1% to 2% of clay stabilizer, 1% to 3% of surfactant, and 62% to 80% of water. The novel oilfield water injection well plugging removal liquid system is prepared according to the following steps: a first step, stirring and mixing the required amount of organic acid and water to obtain a first mixed liquid; a second step, adding the required amount of oilfield complex descaling and plugging removal agent to the first mixed liquid, stirring and mixing to obtain a second mixed liquid; a third step, adding the required amount of corrosion inhibitor, iron ion stabilizer, clay stabilizer and surfactant to the second mixed liquid, stirring and mixing to obtain a novel oilfield water injection well plugging removal liquid system.

[0022] Example 2: As an optimization of the above example, in the first step, the organic acid is aminosulfonic acid and citric acid, the mass ratio of aminosulfonic acid and citric acid is 3:1, the stirring time of the organic acid and water at room temperature is 25min to 35min, and the stirring speed is 30r / min to 40r / min.

[0023] Embodiment 3: As an optimization of the above embodiment, in the second step, the stirring time is 40 min to 50 min at room temperature, and the stirring speed is 30 r / min to 40 r / min.

[0024] Embodiment 4: As an optimization of the above embodiment, in the third step, the stirring time is 10 min to 15 min at room temperature, and the stirring speed is 30 r / min to 40 r / min.

[0025] Embodiment 5: The preparation method of the novel oilfield water injection well plugging removal fluid system comprises: The first step is to stir and mix the required amount of organic acid and water to obtain a first mixed solution; The second step is to add a required amount of the oilfield complex descaling and unblocking agent to the first mixed solution, stir and mix evenly to obtain a second mixed solution; The third step is to add the required amount of corrosion inhibitor, iron ion stabilizer, clay stabilizer and surfactant to the second mixed liquid, stir and mix evenly to obtain a new oilfield water injection well plugging removal liquid system.

[0026] Embodiment 6: As an optimization of the above embodiment, a method for preparing a novel oilfield water injection well plugging removal fluid system comprises: a first step, mixing aminosulfonic acid and citric acid in a mass ratio of 3:1 and then stirring with water, stirring at a speed of 30 r / min to 40 r / min for 25 min to 35 min under a normal temperature environment, and obtaining 10% to 15% of organic acid by weight percentage; The second step is to add 5% to 10% of the oilfield complexing descaling and unblocking agent to 10% to 15% of the organic acid by weight percentage, and stir at a speed of 30r / min to 40r / min for 40min to 50min at room temperature to obtain a second mixed solution; The third step is to add 2% to 5% of corrosion inhibitor, 1% to 3% of iron ion stabilizer, 1% to 2% of clay stabilizer, and 1% to 3% of surfactant to the second mixed liquid by weight percentage, and stir at a speed of 30r / min to 40r / min for 10min to 15min under normal temperature to obtain a novel oilfield water injection well plugging removal liquid system; The novel oilfield water injection well plugging removal fluid system comprises, by weight percentage, 10% to 15% of organic acid, 5% to 10% of oilfield complexing descaling and plugging removal agent, 2% to 5% of corrosion inhibitor, 1% to 3% of iron ion stabilizer, 1% to 2% of clay stabilizer, 1% to 3% of surfactant, and 62% to 80% of water.

[0027] Embodiment 7: As an optimization of the above embodiment, a method for preparing a novel oilfield water injection well plugging removal fluid system comprises: The first step is to mix sulfamic acid and citric acid in a mass ratio of 3:1 and then stir and mix with water, stirring at a speed of 30 r / min for 25 minutes at room temperature to obtain 10% organic acid by weight percentage; The second step is to add 5% of the oilfield complexing descaling and unblocking agent to 10% of the organic acid by weight, and stir at a speed of 30 r / min for 40 minutes at room temperature to obtain a second mixed solution; The third step is to add 2% of corrosion inhibitor, 1% of iron ion stabilizer, 1% of clay stabilizer and 1% of surfactant to the second mixed liquid by weight percentage, and stir at a speed of 30r / min for 10min under normal temperature to obtain a novel oilfield water injection well plugging removal liquid system; The novel oilfield water injection well plugging removal fluid system comprises, by weight percentage, 10% organic acid, 5% oilfield complexing descaling and plugging removal agent, 2% corrosion inhibitor, 1% iron ion stabilizer, 1% clay stabilizer, 1% surfactant, and 80% water.

[0028] Embodiment 8: As an optimization of the above embodiment, a method for preparing a novel oilfield water injection well plugging removal fluid system comprises: The first step is to mix sulfamic acid and citric acid in a mass ratio of 3:1 and then stir and mix with water, stirring at a speed of 35 r / min for 30 minutes at room temperature to obtain 15% organic acid by weight percentage; The second step is to add 8% of the oilfield complexing descaling and unblocking agent to 15% of the organic acid by weight, and stir at a speed of 35 r / min for 45 minutes at room temperature to obtain a second mixed solution; The third step is to add 4% of corrosion inhibitor, 2% of iron ion stabilizer, 2% of clay stabilizer and 2% of surfactant to the second mixed liquid by weight percentage, and stir at a speed of 35r / min for 15min under normal temperature to obtain a novel oilfield water injection well plugging removal liquid system; The novel oilfield water injection well plugging removal fluid system comprises, by weight percentage, 15% of organic acid, 8% of oilfield complexing descaling and plugging removal agent, 4% of corrosion inhibitor, 2% of iron ion stabilizer, 2% of clay stabilizer, 2% of surfactant and 67% of water.

[0029] Embodiment 9: As an optimization of the above embodiment, a method for preparing a novel oilfield water injection well plugging removal fluid system comprises: The first step is to mix sulfamic acid and citric acid in a mass ratio of 3:1 and then stir and mix with water, stirring at a speed of 40 r / min for 35 minutes at room temperature to obtain 13% organic acid by weight percentage; The second step is to add 10% of the oilfield complexing descaling and unblocking agent to 13% of the organic acid by weight percentage, and stir at a speed of 40r / min for 50min at room temperature to obtain a second mixed solution; The third step is to add 5% corrosion inhibitor, 3% iron ion stabilizer, 2% clay stabilizer and 3% surfactant to the second mixed liquid by weight percentage, and stir at a speed of 40r / min for 15min under normal temperature to obtain a novel oilfield water injection well plugging removal liquid system; The novel oilfield water injection well plugging removal fluid system comprises, by weight percentage, 13% organic acid, 10% oilfield complexing descaling and plugging removal agent, 5% corrosion inhibitor, 3% iron ion stabilizer, 2% clay stabilizer, 3% surfactant and 64% water.

[0030] Embodiment 10: The method for using the novel oilfield water injection well plugging removal fluid system comprises: In the first step, the required amount of pretreatment liquid aromatic hydrocarbons is injected into the well to dissolve most of the organic scale at the bottom of the well and near the wellbore; The second step is to inject water into the well to displace the aromatic hydrocarbons in the pre-treatment liquid in the well to the bottom of the well and the deeper area near the well. After stopping the injection, the well is shut down for the reaction time to dissolve all organic scales at the bottom of the well and the area near the well. The third step is to inject a new oilfield water injection well plugging removal fluid system into the well to remove the partial blockage of the oilfield production layer near the wellbore; The fourth step is to inject water into the well to displace the new oilfield water injection well unblocking fluid system in the well to a deeper level in the oilfield production layer near the wellbore. After stopping the injection, shut down the well for the reaction time required to remove all blockages in the oilfield production layer in the wellhead area and open the well for normal production injection.

[0031] Example 11: As an optimization of the above example, the shut-in reaction time after stopping injection in the second step is 2 hours to 4 hours or / and; the shut-in reaction time after stopping injection in the fourth step is 48 hours and above, and then normal production injection is carried out.

[0032] Example 12: As an optimization of the above example, in the first step, the aromatic hydrocarbons in the pretreatment liquid are 60% xylene, 35% kerosene, and 5% propylene glycol by weight.

[0033] Example 13: As an optimization of the above example, in the first step, the amount of aromatic hydrocarbons in the pretreatment liquid is 1% to 3% by weight of the new oilfield water injection well plugging removal liquid system.

[0034] Example 14: As an optimization of the above example, the amount of aromatic hydrocarbons in the pretreatment liquid is calculated by weight percentage, including: based on a well depth of 1000 meters or less, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be 1% of the new oilfield water injection well deplugging fluid system; based on a well depth between 1000 meters and 2000 meters, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be between 1% and 3% of the new oilfield water injection well deplugging fluid system; when the well depth is 2000 meters or more, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be 3% of the new oilfield water injection well deplugging fluid system.

[0035] As needed, based on the well depth between 1000 meters and 2000 meters, according to the pretreatment effect and cost-effectiveness of the aromatic hydrocarbons in the treatment liquid, the amount of aromatic hydrocarbons in the treatment liquid can be 2% by weight of the new oilfield water injection well declogging fluid system.

[0036] According to Example 1 to Example 14, two water injection wells were selected on site. Due to the blockage in the well, they could not meet the normal design injection requirements. The new oilfield water injection well unblocking fluid system of the present invention was used to carry out unblocking construction tests on the water injection wells MHD16239 and MHD16247. The specific situation is as follows: (1) If Figure 1 As shown, test well MHD16239: injection well depth 1946 meters, Figure 1It can be seen that before the unblocking construction, the pressure in the water distribution room was 12Mpa, the oil pressure (wellhead injection pressure) was 12Mpa, and the daily injection was 15m 3 (Design requirements for daily water injection volume of water injection wells), daily actual injection 4m 3 (The actual daily water injection volume of the injection well) cannot meet the injection requirements; on April 29, 2024, the present invention was used to unblock the well, and the specific steps are as follows: The first step is to convert 2m 3 Pre-treatment liquid aromatic hydrocarbons are injected into the well (injection displacement is 0.2m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), dissolve most of the organic scale at the bottom of the well and near the well area; As required, before injecting pre-treatment liquid aromatic hydrocarbons into the well in the first step, a water injection strength test with a pump pressure of 24MPa is required to ensure the safety of the well's water injection pipeline and equipment.

[0037] The second step is to inject 8m 3 Water (injection volume is 0.2m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), displace the aromatic hydrocarbons in the pre-treatment liquid in the well to the bottom of the well and deeper near the well area, shut down the well for reaction for 3 hours after stopping the injection, and dissolve all the organic scale at the bottom of the well and near the well area; The third step is to inject 100m3 of 3 New oilfield water injection well plugging removal fluid system (injection displacement 0.3m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), to relieve partial blockage of oilfield production layer near the wellbore; Among them, the volume usage of the new oilfield water injection well deplugging fluid system is calculated based on the treatment radius, porosity and thickness of the target layer of the well, and then the weight of the new oilfield water injection well deplugging fluid system is estimated based on the density of water.

[0038] Step 4: Inject 8m3 of 3 Water (injection volume is 0.3m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), displace the plugging-releasing fluid system of the new oilfield water injection well in the well to a deeper level in the oilfield production layer near the wellbore. After stopping the injection and shutting down the well for reaction for 48 hours, all blockages in the oilfield production layer in the wellbore area are relieved and the well is opened for normal production injection.

[0039] After the present invention implements unblocking of well MHD16239, Figure 1As shown in the figure, the oil pressure (injection pressure at the wellhead) of well MHD16239 dropped to 8MPa, and the daily actual injection (the actual amount of water injected into the injection well per day) rose to 19m 3 Up to 20m 3 , which can meet the injection requirements.

[0040] (2) If Figure 2 As shown, test well MHD16247: injection well depth 1954 meters, Figure 2 It can be seen that before the unblocking construction, the pressure in the water distribution room was 13Mpa, the oil pressure (wellhead injection pressure) was 13Mpa, and the daily injection was 10m 3 (Design requirements for daily water injection volume of water injection wells), actual injection 0m 3 (The actual daily water injection volume of the injection well) cannot meet the injection requirements; on July 10, 2024, the present invention was used to unblock the well, and the specific steps are as follows: The first step is to move 2.5m 3 Pre-treatment liquid aromatic hydrocarbons are injected into the well (injection displacement is 0.2m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), dissolve most of the organic scale at the bottom of the well and near the well area; As required, before injecting pre-treatment liquid aromatic hydrocarbons into the well in the first step, a water injection strength test with a pump pressure of 24MPa is required to ensure the safety of the well's water injection pipeline and equipment.

[0041] The second step is to inject 8m 3 Water (injection volume is 0.2m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), displace the aromatic hydrocarbons in the pre-treatment liquid in the well to the bottom of the well and deeper near the well area, shut down the well for 4 hours after stopping the injection, and dissolve all the organic scale at the bottom of the well and near the well area; The third step is to inject 125m3 into the well. 3 New oilfield water injection well plugging removal fluid system (injection displacement 0.3m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), to relieve partial blockage of oilfield production layer near the wellbore; Among them, the volume usage of the new oilfield water injection well deplugging fluid system is calculated based on the treatment radius, porosity and thickness of the target layer of the well, and then the weight of the new oilfield water injection well deplugging fluid system is estimated based on the density of water.

[0042] Step 4: Inject 8m3 of 3 Water (injection volume is 0.3m 3 / min to 0.6m 3 / min, pump pressure ≤22MPa), displace the plugging-releasing fluid system of the new oilfield water injection well in the well to a deeper level in the oilfield production layer near the wellbore. After stopping the injection and shutting down the well for reaction for 48 hours, all blockages in the oilfield production layer in the wellbore area are relieved and the well is opened for normal production injection.

[0043] In summary, after the present invention implements unblocking of well MHD16247, Figure 2 As shown in the figure, the oil pressure (injection pressure at the wellhead) of well MHD16247 dropped to 6Mpa to 8Mpa, and the daily actual injection (the actual amount of water injected into the injection well per day) rose to 19m 3 Up to 20m 3 , which can meet the injection requirements.

[0044] The above technical features respectively constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A novel oilfield water injection well plugging removal fluid system, characterized in that The novel oilfield water injection well plugging removal liquid system is prepared according to the following steps: the first step is to stir and mix the required amount of organic acid and water to obtain a first mixed liquid; the second step is to add the required amount of oilfield complex descaling and plugging removal agent to the first mixed liquid, stir and mix to obtain a second mixed liquid; the third step is to add the required amount of corrosion inhibitor, iron ion stabilizer, clay stabilizer and surfactant to the second mixed liquid, stir and mix to obtain a novel oilfield water injection well plugging removal liquid system.

2. The novel oilfield water injection well plugging removal fluid system according to claim 1 is characterized in that In the first step, the organic acid is aminosulfonic acid and citric acid, the mass ratio of aminosulfonic acid to citric acid is 3:1, the organic acid and water are stirred for 25 min to 35 min at room temperature, and the stirring speed is 30 r / min to 40 r / min.

3. The novel oilfield water injection well plugging removal fluid system according to claim 1 or 2, characterized in that In the second step, the stirring time is 40 min to 50 min at room temperature, and the stirring speed is 30 r / min to 40 r / min.

4. The novel oilfield water injection well plugging removal liquid system according to claim 1, 2 or 3, characterized in that In the third step, the stirring time is 10 min to 15 min at room temperature, and the stirring speed is 30 r / min to 40 r / min.

5. A method for preparing a novel oilfield water injection well plugging removal liquid system according to any one of claims 1 to 4, characterized in that include: The first step is to stir and mix the required amount of organic acid and water to obtain a first mixed solution; The second step is to add a required amount of the oilfield complex descaling and unblocking agent to the first mixed solution, stir and mix evenly to obtain a second mixed solution; The third step is to add the required amount of corrosion inhibitor, iron ion stabilizer, clay stabilizer and surfactant to the second mixed liquid, stir and mix evenly to obtain a new oilfield water injection well plugging removal liquid system.

6. A method for using the novel oilfield water injection well plugging removal liquid system according to any one of claims 1 to 4, characterized in that include: In the first step, the required amount of pretreatment liquid aromatic hydrocarbons is injected into the well to dissolve most of the organic scale at the bottom of the well and near the wellbore; The second step is to inject water into the well to displace the aromatic hydrocarbons in the pre-treatment liquid in the well to the bottom of the well and the deeper area near the well. After stopping the injection, the well is shut down for the reaction time to dissolve all organic scales at the bottom of the well and the area near the well. The third step is to inject a new oilfield water injection well plugging removal fluid system into the well to remove the partial blockage of the oilfield production layer near the wellbore; The fourth step is to inject water into the well to displace the new oilfield water injection well unblocking fluid system in the well to a deeper level in the oilfield production layer near the wellbore. After stopping the injection, shut down the well for the reaction time required to remove all blockages in the oilfield production layer in the wellhead area and open the well for normal production injection.

7. The method for using the novel oilfield water injection well plugging removal liquid system according to claim 6 is characterized in that The reaction time of shutting down the well after stopping injection in the second step is 2 hours to 4 hours; or / and, the reaction time of shutting down the well after stopping injection in the fourth step is 48 hours and above, and then normal production injection is carried out.

8. The method for using the novel oilfield water injection well plugging removal liquid system according to claim 6 or 7, characterized in that In the first step, the aromatic hydrocarbons in the pretreatment liquid are 60% by weight of xylene, 35% by weight of kerosene, and 5% by weight of propylene glycol.

9. The method for using the novel oilfield water injection well plugging removal liquid system according to claim 6, 7 or 8, characterized in that In the first step, the amount of aromatic hydrocarbons in the pretreatment liquid is 1% to 3% by weight of the new oilfield water injection well plugging removal liquid system.

10. The method for using the novel oilfield water injection well plugging removal fluid system according to claim 9, characterized in that The amount of aromatic hydrocarbons in the pretreatment liquid is calculated by weight percentage, including: based on a well depth of 1000 meters or less, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be 1% of the new oilfield water injection well deplugging fluid system; based on a well depth between 1000 meters and 2000 meters, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be between 1% and 3% of the new oilfield water injection well deplugging fluid system; when the well depth is 2000 meters or more, the amount of aromatic hydrocarbons in the treatment liquid is calculated by weight percentage to be 3% of the new oilfield water injection well deplugging fluid system.

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