Composite blocking remover for removing oil field microsphere blocking as well as preparation method and application of composite blocking remover

Abstract

The invention provides a composite blocking remover for removing microsphere blocking of an oil field as well as a preparation method and application of the composite blocking remover, and belongs to the technical field of chemical blocking removal in oil exploitation. The composite blocking remover comprises a pretreatment solution, a pretreatment solution, a main treatment solution and a post-treatment solution, the pretreatment solution and the post-treatment solution are composite ionic liquids, and the composite ionic liquids are formed by compounding alkyl pyridine aluminate ionic liquids and dialkyl pyrrole aluminate ionic liquids. Accurate plug removal is achieved through molecular design, high efficiency and environmental friendliness are achieved, and the method has wide application prospects in multiple fields.

Description

Technical Field

[0001] This invention relates to the field of chemical unblocking technology in oil extraction, and in particular to a composite unblocking agent for removing microsphere blockages in oil fields, its preparation method, and its application. Background Technology

[0002] Microspheres are a type of deep water injection well regulation and drive technology that has been widely studied and applied in oilfields in recent years. They belong to nanopolymers. Nanopolymer microspheres physically block the water phase in microfractures by means of plugging, bridging, and superimposing in the reservoir, thereby increasing the water injection well pressure, expanding the water drive sweep volume, improving the water drive development effect, and ultimately achieving the goal of improving oil and gas recovery. However, with the long-term injection of polymer nanospheres in oilfields in recent years, some water injection wells have encountered the following problems: (1) The injection pressure of some wells and formations is close to the system injection pressure, resulting in under-injection or cessation of injection due to high injection pressure. (2) The polymer is severely under-injected in some wells and formations, or even cannot be injected. (3) After some wells and formations are switched to subsequent water drive, the adaptability is poor, the under-injection is severe, or even cannot be injected. This seriously affects the normal production of oilfields.

[0003] For wells blocked by polymer nanospheres, existing technologies typically employ acidizing agents for unblocking. However, conventional acidizing agents are ineffective and have a short lifespan for wells with under-injection caused by profile modification using aldehyde-crosslinked polymer gels, failing to achieve the desired results. Therefore, a method with good and stable unblocking effects for removing microsphere blockage is urgently needed. Summary of the Invention

[0004] A composite unblocking agent for relieving microsphere blockage in oil fields, comprising a pretreatment liquid, a primary treatment liquid, a secondary treatment liquid, and a posttreatment liquid, wherein the primary treatment liquid and the posttreatment liquid are composite ionic liquids, which are compounded from alkylpyridine aluminate ionic liquid and dialkylpyrrole aluminate ionic liquid.

[0005] Preferably, the pretreatment solution and the main treatment solution are each composed of the following components by mass percentage: HCl 8%-12%, emulsifier 1-3%, clay stabilizer 1-2%, corrosion inhibitor 1-3%, and the balance being water.

[0006] Preferably, the emulsifier is selected from at least one of OP-10 (octylphenol polyoxyethylene ether-10), ABS (sodium dodecylbenzene sulfonate), and AEO-9 (fatty alcohol polyoxyethylene ether-9).

[0007] Preferably, the clay stabilizer is selected from at least one of potassium chloride, ammonium chloride, potassium sulfate, and 2-chloroethyltrimethylammonium chloride.

[0008] Preferably, the corrosion inhibitor is selected from at least one of silicates, benzotriazoles, and polyaspartic acid.

[0009] Preferably, the method for preparing the composite ionic liquid includes: mixing alkylpyridine aluminate ionic liquid and dialkylpyrrole aluminate ionic liquid in a mass ratio of 1.5-2:2-3, and keeping it at 85℃-95℃ for 2-3 hours.

[0010] This invention also provides a method for unclogging the composite unclogging agent used to remove microsphere blockage in oil fields, comprising the following steps: injecting the pretreatment fluid, primary treatment fluid, main treatment fluid, and posttreatment fluid using a forward extrusion method, wherein the injection displacement of the pretreatment fluid is 0.3-0.6 m³. 3 The injection rate of the pretreatment solution is 0.2-0.4 m³ / min. 3 The injection rate of the main treatment fluid is 0.3-0.6 m³ / min. 3 The injection rate of the post-treatment fluid is 0.2-0.4 m³ / min. 3 / min.

[0011] Preferably, the well is first flushed by forward circulation, followed by forward extrusion of pretreatment fluid, forward extrusion of activated water, forward extrusion of pretreatment fluid, forward extrusion of main treatment fluid, forward extrusion of posttreatment fluid, and forward extrusion of activated water. The well is then shut in for 3 hours to allow for reaction, after which the blockage is cleared.

[0012] The beneficial effects of this invention are:

[0013] This invention injects a composite unblocking agent into the formation, which decomposes the microsphere blockage into granular aggregates. Through a long-term soaking reaction, the granular aggregates are further decomposed into molecular mixed liquids, significantly reducing the liquid viscosity. Subsequently, water injection carries the decomposed liquid from the formation, thereby achieving the effects of unblocking the formation, reducing water injection pressure, and increasing water injection volume.

[0014] This invention obtains a composite ionic liquid with strong acidity and good solubility by compounding ionic systems containing different anions.

[0015] This invention transforms the acidity of a composite ionic liquid from a weak Leucine (L) acid to a strong Beta acid (B) acid by dissolving the composite ionic liquid in hydrochloric acid. The system exhibits superacidity, and compared with traditional superacids, the composite ionic liquid superacid has better operational safety. Moreover, the composite ionic liquid has good solubility for both organic and inorganic substances.

[0016] Based on this mechanism, the composite ionic liquid provided by the present invention has the effect of dissolving and dispersing polymer microspheres. By adding the composite ionic liquid slug to the polymer microsphere unblocking solution, the aggregated polymer microspheres can be dissolved and decomposed in the flowing composite ionic liquid.

[0017] From a physical perspective, the composite ionic liquid provided by this invention has a wide liquid temperature range, is not easily lost through volatilization, and is environmentally friendly and pollution-free. From a chemical stability perspective, the composite ionic liquid provided by this invention not only overcomes the defects of single ionic liquids but also improves overall performance and can remain stable under various chemical reaction conditions.

[0018] The composite ionic unblocking agent provided by this invention for unblocking oilfield microspheres can efficiently decompose polymer gels and their cross-linking systems, with a high unblocking rate (≥95%) and low corrosion.

[0019] This invention employs a step-by-step deep unblocking slug combination. The pretreatment and main treatment slugs primarily clean the scale and oil coating the surface of the blockage, facilitating direct contact between the unblocking agent and the blockage. Furthermore, the pretreatment and main treatment slugs also reduce the injection pressure of the unblocking agent. The pretreatment slug degrades polymers and their polymer micelles, clearing the formation. The posttreatment slug, used for deep-penetration slug advancement, modifies the sandstone surface to prevent further polymer adsorption and blockage, improving injection efficiency and extending the effective period. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the optimized L-composite ionic liquid slug of the present invention. Detailed Implementation

[0021] In the following technical solutions, the main unblocking fluid refers to both the pretreatment fluid and the posttreatment fluid. The secondary unblocking fluid refers to both the pretreatment fluid and the main treatment fluid. Emulsifier: Sodium dodecylbenzenesulfonate; Clay stabilizer: Ammonium chloride; Corrosion inhibitor: Polyaspartic acid.

[0022] All raw materials used in this invention are commercially available products.

[0023] The alkylpyridine aluminate ionic liquid added in the following examples or comparative examples was purchased from Keneng (Xi'an) Materials Technology Co., Ltd., product model number 356-15-258.

[0024] The added dialkylpyrrole aluminate ionic liquid was purchased from Keneng (Xi'an) Materials Technology Co., Ltd., product model number 347-1-36.

[0025] Example 1

[0026] A composite unblocking agent for relieving microsphere blockage in oilfields, comprising a pretreatment solution, a primary treatment solution, a secondary treatment solution, and a post-treatment solution. The primary and post-treatment solutions are composite ionic liquids, prepared by mixing alkylpyridine aluminate ionic liquid and dialkylpyrrole aluminate ionic liquid in a 2:3 mass ratio and maintaining the mixture at 85℃-95℃ for 2-3 hours.

[0027] The pretreatment solution consists of the following components by mass percentage: HCl 12%, emulsifier 2%, clay stabilizer 1%, corrosion inhibitor 1%, and the balance being water.

[0028] The main treatment fluid consists of the following components by mass percentage: HCl 12%, emulsifier 2%, clay stabilizer 1%, corrosion inhibitor 1%, and the balance being water.

[0029] Example 2

[0030] The difference from Example 1 is that the pretreatment solution is composed of the following components by mass percentage: HCl 10%, emulsifier 3%, clay stabilizer 1%, corrosion inhibitor 1%, and the balance being water.

[0031] The main treatment fluid consists of the following components by mass percentage: HCl 10%, emulsifier 3%, clay stabilizer 1%, corrosion inhibitor 1%, and the balance being water.

[0032] Application Example 1

[0033] Hime 38-23 Well

[0034] The well underwent microsphere injection in May 2022, but began to experience under-injection in November 2022 due to high formation pressure, with an average daily under-injection of 9.3 m³. 3 On December 18th, due to high formation pressure, injection was insufficient, resulting in a daily injection shortfall of 20m³. 3 Following the winter shutdown, in April 2023, the second round of microsphere-based water injection was implemented to restore water supply, with a daily injection volume of 20m³. 3 Daily actual betting volume is 5m3, with an average daily under-betting volume of 15m3. 3 In June 2023, injection failed due to high formation pressure, and 20m³ of additional injection was required. 3 Oil pressure 12.5MPa, casing pressure 12.5MPa, daily injection 0m 3 Daily underpayment of 20m 3 As of now, it is temporarily closed pending additional registrations as of October 2023.

[0035] Construction of the well began at 14:50 on October 22, 2024, powered by a 700-type cement pump truck. A total of 20 m³ of the main unblocking fluid prepared in Example 1 and 20 m³ of the auxiliary unblocking fluid prepared in Example 1 were used.

[0036] The unblocking method of the composite unblocking agent is as follows:

[0037] 1. Inject the pretreatment solution.

[0038] 1.1: Positive circulation well washing: pressure 4MPa, discharge 600L / min, water usage 11m³.

[0039] 1.2: 4 m³ of pretreatment liquid, 4 MPa pressure, and 400 L / min discharge rate.

[0040] 1.3: 4.5 m³ of active water, 5 MPa pressure, and 400 L / min discharge rate.

[0041] 1.4: Close the sleeve, squeeze 3m³ of active water at a pressure of 15MPa and a discharge rate of 400L / min.

[0042] 1.5: Well shut-in reaction time 60 minutes.

[0043] 1.6: Activated water reverse circulation well washing 11m³, pressure 5MPa, discharge rate 500L / min.

[0044] 1.7: 7 m³ of pretreatment solution, 5 MPa pressure, and 400 L / min discharge rate.

[0045] 2. Throw the ball, seal the packer, and open the acidized sliding sleeve.

[0046] 2.1: Throw a φ35mm ball to set the seal. Throw the ball, wait 30 minutes, and after the ball settles, pressurize the seal in stages (5MPa-10MPa-15MPa); when the pressure reaches 17MPa, the sliding sleeve opens. The sleeve does not backflow, and the seal is in good condition.

[0047] 2.2: Throw a φ45mm ball to open the acidified sliding sleeve. Throw the ball, wait 30 minutes, and after the ball settles, pressurize to 15MPa to open the sliding sleeve.

[0048] 3. Inject the main treatment solution.

[0049] 3.1: Pretreatment liquid for forward extrusion 3m³, pressure change 16MPa, discharge rate 400L / min.

[0050] 3.2: Forward extrusion of active water isolation fluid 1m³: pressure 15MPa, discharge rate 400L / min.

[0051] 3.3: Forward extrusion of main treatment fluid 16m³: pressure 16-18MPa, discharge rate 400L / min.

[0052] 3.4: Forward extrusion of active water isolation fluid 1m³: pressure 16MPa, discharge rate 400L / min.

[0053] 3.5: Post-extrusion treatment liquid 10m³: pressure 16MPa, discharge 400L / min.

[0054] 3.6: Forward extrusion of 15m³ of activated water: pressure 16MPa, discharge rate 400L / min.

[0055] The well is shut in for 3 hours, followed by a high-volume backwash.

[0056] 4. Residual acid backflow: Blow out the flow, reverse the circulation to flush the well, and flush until the inlet and outlet liquids are the same.

[0057] 5. Run the well casing.

[0058] Construction Summary: Pressure Changes: The pressure of the main treatment fluid during forward extrusion reached a maximum of 18 MPa and a minimum of 16 MPa. The pump stop pressure was 12 MPa, and the discharge rate remained at 400 L / min. The construction was continuous and smooth, indicating that the blockage and scaling were effectively resolved, and the objectives of the measures were achieved.

[0059] Experimental results:

[0060] Table 1 shows the comparison of injection in well Ji 38-23 before and after the measures.

[0061] Table 1

[0062]

[0063] After normal well opening, the injection pressure decreased by 2 MPa, and the cumulative injection volume increased by 1800 m³ in 120 days, with an average daily increase of 15 m³.

[0064] Application Example 2

[0065] Well Yuan 451-59

[0066] The well was put into production in November 2016, with a production layer length of 9 and an initial daily injection rate of 10m³. 3 10m daily betting 3 The oil pressure is 5.0 MPa; polymer microspheres were injected in September 2017, but under-injection began in January 2018, and well washing and squeezing injections were ineffective; currently, the daily injection volume is 10 m³, and the actual daily injection volume is 0 m³. 3 The wellhead oil pressure is 18.4 MPa.

[0067] Construction of the well commenced at 12:45 on March 11, 2018. The composite unblocking agent prepared in Example 1 was used to unblock and increase injection in well sections 2398.0-2406.0m and 2408.0-2411.0m. A 700-type cement pump truck was used as the power unit. A total of 12m³ of the main unblocking fluid prepared in Example 1 and 12m³ of the auxiliary unblocking fluid prepared in Example 1 were used.

[0068] The unblocking method of the composite unblocking agent is as follows:

[0069] 1. Inject the pretreatment solution.

[0070] 1.1: Positive circulation well washing: pressure 4MPa, discharge 500L / min, water usage 11m³.

[0071] 1.2: 4 m³ of pretreatment liquid, 4 MPa pressure, and 400 L / min discharge rate.

[0072] 1.3: 4.5 m³ of active water, 4 MPa pressure, and 400 L / min discharge rate.

[0073] 1.4: Close the sleeve, squeeze 3m³ of active water at a pressure of 15MPa and a discharge rate of 400L / min.

[0074] 1.5: Well shut-in reaction time 60 minutes.

[0075] 1.6: Activated water reverse circulation well washing 11m³, pressure 5MPa, discharge rate 500L / min.

[0076] 1.7: 7 m³ of pretreatment solution, 5 MPa pressure, and 500 L / min discharge rate.

[0077] 2. Throw the ball, seal the packer, and open the acidized sliding sleeve.

[0078] 2.1: Throw a φ35mm ball to set the seal. Throw the ball, wait 30 minutes, and after the ball settles, pressurize the seal in stages (5MPa-10MPa-15MPa); when the pressure reaches 17MPa, the sliding sleeve opens. The sleeve does not backflow, and the seal is in good condition.

[0079] 2.2: Throw a φ45mm ball to open the acidified sliding sleeve. Throw the ball, wait 30 minutes, and after the ball settles, pressurize to 15MPa to open the sliding sleeve.

[0080] 3. Inject the main treatment solution.

[0081] 3.1: Pretreatment liquid for forward extrusion 3m³, pressure change 17MPa, discharge rate 400L / min.

[0082] 3.2: Forward extrusion of active water isolation fluid 1m³: pressure 16MPa, discharge rate 400L / min.

[0083] 3.3: Forward extrusion of main treatment fluid 16m³: pressure 16-18MPa, discharge rate 400L / min.

[0084] 3.4: Forward extrusion of active water isolation fluid 1m³: pressure 16MPa, discharge rate 400L / min.

[0085] 3.5: Post-extrusion treatment liquid 10m³: pressure 16MPa, discharge 400L / min.

[0086] 3.6: Forward extrusion of 15m³ of activated water: pressure 16MPa, discharge rate 400L / min.

[0087] The well is shut in for 3 hours, followed by a high-volume backwash.

[0088] 4. Residual acid backflow: Blow out the flow, reverse the circulation to flush the well, and flush until the inlet and outlet liquids are the same.

[0089] 5. Run the well casing.

[0090] Construction Summary: Pressure changes, with the highest pressure of the positively extruded active ionic liquid reaching 21 MPa and the lowest reaching 18 MPa, and the pump stop pressure at 13 MPa, while the discharge rate remained at 400 L / min, indicate that the blockage and scaling were effectively resolved and the objectives of the measures were achieved.

[0091] Experimental results:

[0092] Table 2 shows the comparison of injection results in wells 451-59 before and after the measures.

[0093] Table 2

[0094]

[0095] After the well was opened following the unblocking measures, the injection pressure decreased by 4 MPa, and the cumulative injection volume increased by 420 m³ over 60 days, averaging 7 m³ per day.

[0096] Application Example 3

[0097] Jiao 91-451

[0098] Well Jiao 91-451 was put into production in October 2017, producing the Yan 91 formation. In June 2018, it was transferred to inject water into the Yan 91 formation. Cyclic water injection was implemented in September 2020 for one month; microsphere-based water injection was carried out from April 2021 to January 2023; and viscoelastic self-adjustment was implemented from January 2024 to January 2025. In March 2025, the formation pressure rose to 20 MPa, preventing water injection. Backwashing and squeezing injection were then implemented, reducing the pressure to 18.0 MPa, with a daily injection rate of 13.0 m³. Two months later, the formation pressure rose again to 18.5 MPa, preventing water injection.

[0099] Construction of the well commenced at 11:45 AM on July 12, 2025. The composite unblocking agent prepared in Example 1 was used to unblock and increase injection in the 1428.0-1429.5m section of the well. The power unit was a 700-type cement pump truck. A total of 10m³ of main unblocking fluid and 10m³ of auxiliary unblocking fluid were used. The discharge rate was stable, the construction process was continuous, and the measures were completed safely and smoothly.

[0100] 1. Inject the pretreatment solution.

[0101] 1.1: Positive circulation well washing: pressure 3MPa, discharge 700L / min, water usage 7m³.

[0102] 1.2: 2 m³ of pretreatment liquid, pressure 3.5 MPa, discharge rate 450 L / min.

[0103] 1.3: 2m³ of active water, pressure 3.5MPa, discharge rate 450L / min.

[0104] 1.4: Close the sleeve, squeeze 2.5m³ of active water at a pressure of 19MPa and a discharge rate of 300L / min.

[0105] 1.5: Well shut-in reaction 30 minutes.

[0106] 1.6: Activated water reverse circulation well washing 9m³, pressure 2.2MPa, discharge rate 600L / min.

[0107] 1.7: 3 m³ of pretreatment solution for positive displacement, 4 MPa pressure, and 400 L / min discharge rate.

[0108] 1.8: 1.5 m³ of positive displacement fluid, 3 MPa pressure, and 400 L / min discharge rate.

[0109] 2. Throw the ball, seal the packer, and open the acidized sliding sleeve.

[0110] 2.1: Throw the ball, wait 20 minutes, and after the ball settles, gradually pressurize the sealing seal (5MPa-10MPa-15MPa); when the pressure reaches 15MPa, the sliding sleeve opens. The sleeve does not backflow, and the sealing seal is in good condition.

[0111] 3. Squeeze in the main acid.

[0112] 3.1: Forward extrusion main treatment liquid 8m³: pressure 16-19MPa, discharge rate 400L / min.

[0113] 3.2: Forward extrusion of active water isolation fluid 1m³: pressure 14MPa, discharge rate 400L / min.

[0114] 3.3: Post-extrusion treatment liquid 7m³: pressure 14MPa, discharge rate 400L / min.

[0115] 3.4: Forward extrusion of 10m³ of activated water: pressure 14MPa, discharge rate 400L / min.

[0116] The well is shut in for 3 hours, followed by a high-volume backwash.

[0117] 4. Residual acid backflow: Blow out the flow, reverse the circulation to flush the well, and flush until the inlet and outlet liquids are the same.

[0118] 5. Run the well casing.

[0119] Construction Summary: Pressure changes: The main treatment fluid pressure rose to a maximum of 19 MPa and a minimum of 14 MPa. The pump stop pressure was 12.5 MPa, and the discharge rate remained at 400 L / min. The construction was continuous and smooth, indicating that the blockage and scaling were effectively resolved and the objectives of the measures were achieved.

[0120] Experimental results:

[0121] Table 3 shows the comparison of injection in well 91-451 before and after the measures.

[0122] Table 3

[0123]

[0124] After normal well opening, the injection pressure decreased by 5.4 MPa, and the cumulative injection volume increased by 450 m³ over 30 days, averaging 15 m³ per day.

[0125] Comparative Example 1

[0126] The difference from Example 1 is that the composite ionic liquid is an alkylpyridine aluminate ionic liquid.

[0127] Comparative Example 2

[0128] The difference from Example 1 is that the composite ionic liquid is a dialkylpyrrole aluminate ionic liquid.

[0129] The oxidative breaking ability of Example 1 and Comparative Examples 1-2 on HPAM and crosslinking systems was tested.

[0130] Experimental method: Under room temperature conditions, 200 mL of HPAM, HPAM chromium crosslinking system, HPAM aldehyde crosslinking system, and well bottom return material were measured and poured into four 500 mL graduated cylinders respectively. 100 mL of the composite ionic liquid prepared in Example 1, Comparative Example 1, and Comparative Example 2 were added to the four graduated cylinders respectively. After stirring thoroughly and standing for 6 hours, the viscosity and breakage rate of the four solutions were tested after 12 hours. The results are shown in Table 4-6.

[0131] Table 4 (Example 1)

[0132] Group HPAM HPAM Chromium Crosslinking System HPAM aldehyde crosslinking system Well bottom regurgitation Breakage rate / % 100 100 100 Completely broken Residual fluid viscosity after unblocking / mPa.s 1.0 1.3 1.5 1.8

[0133] Table 5 (Comparative Example 1)

[0134] Group HPAM HPAM Chromium Crosslinking System HPAM aldehyde crosslinking system Well bottom regurgitation Breakage rate / % 75 60 65 80 Residual fluid viscosity after unblocking / mPa.s 8.5 12.3 25.1 18.6

[0135] Table 6 (Comparative Example 2)

[0136] Group HPAM HPAM Chromium Crosslinking System HPAM aldehyde crosslinking system Well bottom regurgitation Breakage rate / % 78 66 70 73 Residual fluid viscosity after unblocking / mPa.s 9.3 11.5 22.4 16.9

[0137] As shown in Tables 4-6, the composite unblocking agent provided in Example 1 has excellent gel breaking and dispersing effects on the polyacrylamide and chromium crosslinking and aldehyde crosslinking systems, as well as bottom-hole backflow material. The gel breaking rate reaches 100%, and the residual liquid viscosity is also significantly reduced, basically approaching the viscosity of water, which helps to degrade, disperse, and remove microsphere blockages from the formation. In contrast, the gel breaking rate and residual liquid viscosity of Comparative Example 1 or Comparative Example 2 are not as good as those of Example 1.

[0138] The corrosion rate (according to SY-T5273-2014, the performance evaluation method of corrosion inhibitors for oilfield produced water) and the unblocking rate (according to SY / T5358-2010, the unblocking rate was calculated by measuring the permeability of the core before and after unblocking through core flow experiments) of the unblocking agents prepared in Examples 1-2 and Comparative Examples 1-2 were tested, and the results are shown in Table 7.

[0139] Table 7

[0140] Group <![CDATA[Corrosion rate (g / m 2 ·h)]]> Congestion relief rate (%) Example 1 0.91 96 Example 2 0.95 93 Comparative Example 1 1.12 65 Comparative Example 2 1.22 70

[0141] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite unblocking agent for removing microsphere blockage in oil fields, characterized in that, The composite unblocking agent includes a pretreatment liquid, a pretreatment liquid, a main treatment liquid, and a posttreatment liquid. The pretreatment liquid and the posttreatment liquid are composite ionic liquids, which are compounded from alkylpyridine aluminate ionic liquid and dialkylpyrrole aluminate ionic liquid.

2. The composite unblocking agent for removing microsphere blockage in oil fields according to claim 1, characterized in that, The pretreatment solution and the main treatment solution are each composed of the following components by mass percentage: HCl 8%-12%, emulsifier 1-3%, clay stabilizer 1-2%, corrosion inhibitor 1-3%, and the balance being water.

3. The composite unblocking agent for removing microsphere blockage in oil fields according to claim 2, characterized in that, The emulsifier is selected from at least one of OP-10, ABS, and AEO-9.

4. The composite unblocking agent for removing microsphere blockage in oil fields according to claim 2, characterized in that, The clay stabilizer is selected from at least one of quaternary ammonium salt clay stabilizers and ammonium chloride cationic composite clay stabilizers.

5. The composite unblocking agent for removing microsphere blockage in oil fields according to claim 2, characterized in that, The corrosion inhibitor is selected from at least one of inorganic corrosion inhibitors, organic corrosion inhibitors, and polymer corrosion inhibitors.

6. The composite unblocking agent for removing microsphere blockage in oil fields according to claim 1, characterized in that, The method for preparing the composite ionic liquid includes: mixing alkylpyridine aluminate ionic liquid and dialkylpyrrole aluminate ionic liquid in a mass ratio of 1.5-2:2-3, and keeping it at 85℃-95℃ for 2-3 hours.

7. The unblocking method of the composite unblocking agent for unblocking oilfield microspheres according to any one of claims 1-6, characterized in that, The process includes the following steps: injecting the pretreatment liquid, pretreatment liquid, main treatment liquid, and posttreatment liquid using a forward extrusion method.

8. The unblocking method of the composite unblocking agent for unblocking oilfield microspheres according to claim 7, characterized in that, The injection rate of the pretreatment solution is 0.3-0.6 m³. 3 The injection rate of the pretreatment solution is 0.2-0.4 m³ / min. 3 / min.

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