Delayed heat release chemical blocking remover for oil layer of oil field as well as preparation method and application of delayed heat release chemical blocking remover

Abstract

The invention discloses an oil field oil layer delayed heat release chemical blocking remover and a preparation method and application thereof, and relates to the field of oil field development technologies. Raw materials comprise a component A, a component B and a catalyst; the component A comprises the following raw materials in percentage by mass: 20-31% of ammonium chloride and 69-80% of water; the component B comprises the following raw materials in percentage by mass: 26-40% of sodium nitrite, 4-6% of solvent oil, 1-2% of mixed aromatic hydrocarbon, 1-2% of an emulsifier, 0.2-1.5% of a paraffin dispersant, 1-2% of a mutual solvent, 0.5-1% of alkyl sulfonic acid metal salt and 47.8-64% of water; the catalyst is monopotassium phosphate. The chemical blocking remover provided by the invention not only has excellent wax dissolving and preventing effects, but also has the characteristics of controllable reaction time and delayed heat release, can be adjusted according to site requirements, is suitable for different well depths, is convenient for site construction, and does not pollute an oil layer.

Description

Technical Field

[0001] The present application relates to the field of oilfield development technology, and in particular to an oilfield oil layer delayed exothermic chemical plugging remover and a preparation method and application thereof. Background Art

[0002] In the process of oil and gas field production, low formation or environmental temperature often brings some unfavorable factors to the exploitation, such as wax deposition in the formation and wellbore, cold damage to the formation by hydraulic fracturing, etc., which will cause wax deposition in the formation around the wellbore, resulting in reduced formation permeability, increased difficulty in exploitation, and increased exploitation costs. In the prior art, the near-wellbore area is heated mainly by chemical reaction heat release, so as to achieve the purpose of unblocking and removing wax.

[0003] The commonly used chemical heat generating system at present is the heat generating system of nitrite and ammonium chloride, which is a cheap and readily available common chemical reagent. It can react under acid catalysis to produce a large amount of heat and gas, so it is widely used on site. The chemical reaction equation is as follows:

[0004] However, in actual production and construction, the acid catalysts used in the reaction of sodium nitrite and ammonium chloride are mainly hydrochloric acid, oxalic acid, etc., which generally cause a reaction very quickly. Although the intended purpose can be achieved, the reaction will occur during the construction process, which brings great safety hazards to the construction. In addition, near the formation, due to the relatively high temperature and pressure, wax deposition is generally not too serious. On the contrary, in the process of crude oil flowing from the bottom of the well to the wellhead, its temperature and pressure will drop to varying degrees. When the temperature drops below the wax precipitation point, wax will precipitate from the crude oil to form wax crystals, which will attach to the wall of the oil casing and seriously affect the normal production of the oil well. Therefore, if the reaction speed of the chemical heat generation system is too fast, it will also cause the utilization efficiency of the heat generation main agent to be low and the wax dissolution rate to be low. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present application provides an oilfield oil layer delayed exothermic chemical plugging remover and a preparation method and application thereof.

[0006] The present application provides an oilfield oil layer delayed exothermic chemical plugging remover, which adopts the following technical solution: A delayed exothermic chemical plugging remover for oilfield oil layers, the raw materials of which include component A, component B and a catalyst; the raw materials in component A include 20-31% of ammonium chloride and 69-80% of water by mass percentage; the raw materials in component B include 26-40% of sodium nitrite, 4-6% of solvent oil, 1-2% of mixed aromatic hydrocarbons, 1-2% of emulsifier, 0.2-1.5% of paraffin dispersant, 1-2% of mutual solvent, 0.5-1% of alkyl sulfonic acid metal salt and 47.8-64% of water by mass percentage; the mass ratio of component A, component B and catalyst is 1:0.9-1.1:0.03-0.1; the catalyst is potassium dihydrogen phosphate.

[0007] Preferably, the catalyst further comprises an auxiliary agent; the auxiliary agent is polyferric sulfate.

[0008] Preferably, the mass ratio of potassium dihydrogen phosphate to polyferric sulfate is 1:0.01-0.07.

[0009] Preferably, the polymerized ferric sulfate is prepared from the following raw materials in parts by weight: 27.9-41.9 parts of ferrous sulfate, 70-105 parts of distilled water, 1.66-2.49 parts of concentrated sulfuric acid, and 5.5-8.3 parts of hydrogen peroxide.

[0010] Preferably, the method for preparing the polyferric sulfate comprises the following steps: Add distilled water to ferrous sulfate, stir until dissolved, then add concentrated sulfuric acid, stir evenly to obtain a mixed solution, heat the mixed solution to 20-30°C in a water bath, drop hydrogen peroxide, and control the dropping time to 30-40min; then heat to 50-60°C, perform hydrolysis polymerization reaction for 3-5h, take out, mature at room temperature for 24-30h to obtain a liquid product, and freeze-dry the liquid product to obtain solid polyferric sulfate.

[0011] Preferably, the mixed aromatic hydrocarbons are composed of benzene, toluene, xylene, trimethylbenzene and ethylbenzene; the mass ratio of benzene, toluene, xylene, trimethylbenzene and ethylbenzene is 3-5:2-3:10-20:2.5-5:2.5-5.

[0012] Preferably, the alkyl sulfonate metal salt is C10-C20 alkyl sulfonate sodium salt.

[0013] Preferably, the emulsifier is a mixture of one or more of Tween, OP-10 and Span.

[0014] The present application provides a method for preparing a delayed exothermic chemical plugging remover for oilfield oil layers, which adopts the following technical scheme: A method for preparing a delayed exothermic chemical plugging remover for an oil field oil layer comprises the following steps: 20-31% ammonium chloride and 69-80% water are mixed uniformly according to mass percentage to obtain component A; 26-40% sodium nitrite, 4-6% solvent oil, 1-2% mixed aromatic hydrocarbons, 1-2% emulsifier, 0.2-1.5% paraffin dispersant, 1-2% mutual solvent, 0.5-1% alkyl sulfonic acid metal salt, and 47.8-64% water are mixed uniformly according to mass percentage to obtain component B; preparing a catalyst; After mixing component A, component B and the catalyst, a chemical plugging remover with delayed heat release is obtained.

[0015] The application of an oilfield oil layer delayed exothermic chemical plugging remover provided in the present application adopts the following technical solution: The invention discloses an application of a delayed exothermic chemical plugging remover for oil field oil layers, and the application of the chemical plugging remover in clearing wax and unblocking oil field oil layers.

[0016] In summary, the present application includes at least one of the following beneficial technical effects: 1. By adopting the above technical solution, the present application uses potassium dihydrogen phosphate as a catalyst for the reaction of sodium nitrite and ammonium chloride. Potassium dihydrogen phosphate can slowly ionize H in water. + To catalyze the reaction of nitrite and ammonium chloride, the ionization equation is as follows: H2PO4 - → HPO4 2- + H + HPO4 2- →PO4 3- + H + ; As the reaction H + The continuous consumption of KH2PO4 continuously ionizes H + , thereby achieving the purpose of delayed heat release; and the reaction speed can be controlled by adjusting the amount of catalyst, so that a violent chemical reaction occurs within a predetermined time range at a predetermined depth of the oil layer, generating a large amount of gas and releasing huge heat, forming high temperature and high pressure locally, so that organic matter such as wax, asphalt and colloid deposited in the area around the wellbore and in the wellbore can be melted, and then sprayed out from the casing return discharge, effectively improving the wax dissolving rate of the chemical plugging remover; it can be adjusted according to the needs of the site, suitable for different well depths, convenient for on-site construction, and will not pollute the oil layer; 2. The present application can also use polyferric sulfate as an auxiliary agent for the catalyst potassium dihydrogen phosphate. Polyferric sulfate will react chemically with the phosphate ions ionized from potassium dihydrogen phosphate to form an insoluble iron phosphate precipitate, which can promote the ionization process of potassium dihydrogen phosphate in water and accelerate H +The production of potassium dihydrogen phosphate broadens the temperature range of the reaction; and the generated insoluble iron phosphate precipitate is also a good flocculant, which can effectively remove impurities and suspended matter in the oil field through adsorption, charge neutralization, mutual attraction and coagulation, thereby improving the plugging removal effect; 3. The present application adopts mixed aromatic hydrocarbons to replace the single aromatic hydrocarbons in the prior art, which has a certain synergistic effect and can effectively improve the wax dissolution rate; the present application also adds alkyl sulfonate metal salts, which have a good anti-wax effect and have good dispersibility. When the wax melts, it will disperse the molten wax into fine particles, so that it remains in a dispersed state after cooling and is not easy to aggregate, thereby achieving the purpose of anti-wax. DETAILED DESCRIPTION

[0017] The present application is further described in detail below with reference to the embodiments.

[0018] The chemical reagents used in the preparation examples, embodiments and comparative examples provided by the present invention are all commercially available products, and their brands and manufacturers are as follows: Paraffin dispersant, Anqiu Luxing Trading Co., Ltd.; Mutual solvent; Weifang Youbo Chemicals Co., Ltd.

[0019] Preparation Example 1: Add 75 g of distilled water to 27.9 g of ferrous sulfate, stir until dissolved, then add 1.66 g of concentrated sulfuric acid, stir evenly to obtain a mixed solution, heat the mixed solution to 20° C. in a water bath, drop 5.5 g of hydrogen peroxide, and control the dropping time to 30 min; then heat to 50° C., hydrolyze and polymerize for 3 h, then take out, mature at room temperature for 24 h to obtain a liquid product, and freeze-dry the liquid product to obtain solid polyferric sulfate.

[0020] Preparation Example 2: Add 88 g of distilled water to 34.9 g of ferrous sulfate, stir until dissolved, add 2.08 g of concentrated sulfuric acid, stir evenly to obtain a mixed solution, heat the mixed solution to 25 ° C in a water bath, drop 7.4 g of hydrogen peroxide, and control the dropping time to 35 min; then heat to 55 ° C, hydrolyze and polymerize for 4 hours, then take out, mature at room temperature for 27 hours to obtain a liquid product, and freeze-dry the liquid product to obtain solid polyferric sulfate.

[0021] Preparation Example 3: Add 105 g of distilled water to 41.9 g of ferrous sulfate, stir until dissolved, then add 2.49 g of concentrated sulfuric acid, stir evenly to obtain a mixed solution, heat the mixed solution to 30 ° C in a water bath, drop 8.3 g of hydrogen peroxide, and control the dropping time to 40 min; then heat to 60 ° C, hydrolyze and polymerize for 5 hours, then take out, mature at room temperature for 30 hours to obtain a liquid product, and freeze-dry the liquid product to obtain solid polyferric sulfate.

[0022] Example 1: In this example, the mass ratio of the mixed aromatics benzene, toluene, xylene, trimethylbenzene and ethylbenzene is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 64% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 90 g of component B and 3 g of potassium dihydrogen phosphate, a chemical plugging remover with delayed heat release is obtained.

[0023] Example 2: In this example, the mass ratio of the mixed aromatics benzene, toluene, xylene, trimethylbenzene and ethylbenzene is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 26% ammonium chloride and 74% water in a mass ratio to obtain component A; 33% sodium nitrite, 5% solvent oil, 1.5% mixed aromatic hydrocarbons, 1.5% emulsifier, 0.8% paraffin dispersant, 1.5% mutual solvent, 0.8% alkyl sulfonic acid metal salt, and 55.9% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 90 g of component B and 3 g of potassium dihydrogen phosphate, a chemical plugging remover with delayed heat release is obtained.

[0024] Example 3: In this example, the mass ratio of the mixed aromatics benzene, toluene, xylene, trimethylbenzene and ethylbenzene is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 31% ammonium chloride and 69% water in a mass ratio to obtain component A; 40% sodium nitrite, 6% solvent oil, 1% mixed aromatic hydrocarbon, 2% emulsifier, 0.2% paraffin dispersant, 2% mutual solvent, 1% alkyl sulfonic acid metal salt, and 47.8% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 90 g of component B and 3 g of potassium dihydrogen phosphate, a chemical plugging remover with delayed heat release is obtained.

[0025] Example 4: In this example, the mass ratio of the mixed aromatics benzene, toluene, xylene, trimethylbenzene and ethylbenzene is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 64% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 100 g of component B, and 6.5 g of potassium dihydrogen phosphate, a chemical blocking agent with delayed exothermicity is obtained.

[0026] Example 5: In this example, the mass ratio of the mixed aromatics benzene, toluene, xylene, trimethylbenzene and ethylbenzene is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 64% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 110 g of component B and 0.1 g of potassium dihydrogen phosphate, a chemical blocking agent with delayed heat release is obtained.

[0027] Example 6. The difference between Example 6 and Example 1 is that the mass ratio of the mixed aromatic hydrocarbons benzene, toluene, xylene, trimethylbenzene and ethylbenzene used in Example 6 is 4:2.5:15:3.2:3.2.

[0028] Example 7. The difference between Example 7 and Example 1 is that the mass ratio of the mixed aromatic hydrocarbons benzene, toluene, xylene, trimethylbenzene and ethylbenzene used in Example 7 is 5:3:20:5:5.

[0029] Example 8: The difference between Example 8 and Example 1 is that the alkyl sulfonate metal salt used in Example 8 is sodium hexadecyl sulfonate.

[0030] Example 9: The difference between Example 9 and Example 1 is that the emulsifier used in Example 9 is a mixture of OP-10 and Span 80, and the mass ratio of the two is 1:1.

[0031] Example 10: The difference between Example 10 and Example 1 is that the emulsifier used in Example 10 is Tween 20.

[0032] Example 11, the mass ratio of the mixed aromatics benzene, toluene, xylene, trimethylbenzene and ethylbenzene used in this example is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; the polyferric sulfate used is from Preparation Example 1; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 64% water were mixed uniformly according to mass ratio to obtain component B; The potassium dihydrogen phosphate and the polyferric sulfate are mixed uniformly in a mass ratio of 1:0.01 to obtain a catalyst; S2. After mixing 100 g of component A, 90 g of component B and 3 g of catalyst, a chemical plugging remover with delayed exothermicity is obtained.

[0033] Example 12. The difference between Example 12 and Example 11 is that the potassium dihydrogen phosphate and polyferric sulfate in Example 12 are mixed in a mass ratio of 1:0.04.

[0034] Example 13. The difference between Example 13 and Example 11 is that the potassium dihydrogen phosphate and polyferric sulfate in Example 13 are mixed in a mass ratio of 1:0.07.

[0035] Example 14. The difference between Example 14 and Example 11 is that the potassium dihydrogen phosphate and polyferric sulfate in Example 14 are mixed in a mass ratio of 1:0.005.

[0036] Example 15. The difference between Example 15 and Example 11 is that the potassium dihydrogen phosphate and polyferric sulfate in Example 15 are mixed in a mass ratio of 1:0.1.

[0037] Example 16. The difference between Example 16 and Example 11 is that the polyferric sulfate in Example 16 comes from Preparation Example 2.

[0038] Example 17. The difference between Example 17 and Example 11 is that the polyferric sulfate in Example 17 comes from Preparation Example 3.

[0039] Comparative Example 1: The mass ratio of the mixed aromatic hydrocarbons benzene, toluene, xylene, trimethylbenzene and ethylbenzene used in this comparative example is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 64% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 80 g of component B and 1 g of potassium dihydrogen phosphate, a chemical blocking agent with delayed heat release is obtained.

[0040] Comparative Example 2: The mass ratio of the mixed aromatic hydrocarbons benzene, toluene, xylene, trimethylbenzene and ethylbenzene used in this comparative example is 3:2:10:2.5:2.5; the emulsifier used is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 64% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 80 g of component B and 14 g of potassium dihydrogen phosphate, a chemical plugging remover with delayed heat release is obtained.

[0041] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the catalyst used in Comparative Example 3 is a 30% hydrochloric acid solution.

[0042] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that the aromatic hydrocarbon used in Comparative Example 4 is single xylene, that is, the preparation method of the chemical blocking remover of this comparative example is as follows: The emulsifier used in this comparative example is Span 80; the alkyl sulfonate metal salt used is sodium dodecyl sulfonate; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% xylene, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 64% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 90 g of component B and 3 g of potassium dihydrogen phosphate, a chemical plugging remover with delayed heat release is obtained.

[0043] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that no alkyl sulfonate metal salt is added in Comparative Example 5, that is, the preparation method of the chemical blocking remover of this comparative example is as follows: The mass ratio of the mixed aromatics benzene, toluene, xylene, trimethylbenzene and ethylbenzene used in this comparative example is 3:2:10:2.5:2.5; the emulsifier used is Span 80; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1% emulsifier, 1.5% paraffin dispersant, 1% mutual solvent, and 64.5% water were mixed uniformly according to the mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 90 g of component B and 3 g of potassium dihydrogen phosphate, a chemical plugging remover with delayed heat release is obtained.

[0044] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that no emulsifier is added in Comparative Example 6, that is, the preparation method of the chemical plugging remover of this comparative example is as follows: The mass ratio of the mixed aromatic hydrocarbons benzene, toluene, xylene, trimethylbenzene and ethylbenzene used in this comparative example is 3:2:10:2.5:2.5; the alkyl sulfonic acid metal salt used is sodium dodecyl sulfonate; S1. Mix 20% ammonium chloride and 80% water in a mass ratio to obtain component A; 26% sodium nitrite, 4% solvent oil, 2% mixed aromatic hydrocarbons, 1.5% paraffin dispersant, 1% mutual solvent, 0.5% alkyl sulfonic acid metal salt, and 65% water were mixed uniformly according to mass ratio to obtain component B; Prepare the catalyst potassium dihydrogen phosphate; S2. After mixing 100 g of component A, 90 g of component B and 3 g of potassium dihydrogen phosphate, a chemical plugging remover with delayed heat release is obtained.

[0045] Application Examples The delayed exothermic plugging remover provided in this application can be used for clearing wax and plugging in oil layers in oil fields. The on-site construction process steps are as follows: Step 1: Start the pump: pull out all the pipes and accessories from the well, clean and pierce the oil pipes, measure and check the data; Step 2: Sand flushing: sand flushing from the sand exploration surface to the cement surface; Step 3, hot washing: lower the pipe pin to the designed position and wash the well with hot water in a positive circulation; Step 4: Replace the high-pressure wellhead gate and seal the wellhead; Step 5: Connect the 350 cement truck, truck, high-pressure tee and wellhead liquid pipeline, close the oil and casing gates, and test the wellhead pressure at 15MPa to ensure no puncture or leakage; Step 6, squeezing liquid: prepare the delayed exothermic chemical plugging remover according to the preparation method of Examples 1-16, and prepare component A, component B, and catalyst in tanks A, B, and C respectively; close the oil pipe gate, open the casing gate, fill the casing with formation water, open the oil pipe gate, and squeeze component A, component B, and catalyst from the oil pipe with the same displacement at the same time by three cement trucks (the catalyst may not be squeezed in at the same time); Step 7: Shut-in reaction, slowly control the pressure release, unload the wellhead, wash and flush the sand with a large displacement cycle, and let it settle for 2 hours. The re-exploration sand surface rises less than 2‰, which is qualified; Step 8, well completion: complete the well according to the original pump hanging data.

[0046] Performance testing Using the detection method in SYT 6300-2009 "Technical Requirements for Oil Production Cleaners and Wax Preventers", the wax dissolution rate, wax prevention rate and viscosity reduction rate of the chemical plugging removers obtained in Examples 1-17 and Comparative Examples 1-6 were tested under the same conditions. The results are shown in Table 1.

[0047] The specific test results are as follows:

[0048] It can be seen from the test results in Table 1 that the delayed exothermic chemical plugging remover provided by the present application has a high wax dissolving rate, indicating that the chemical plugging remover provided by the present application has a wax dissolving and wax removing effect; the wax prevention rate is relatively high, indicating that the chemical plugging remover provided by the present application is not conducive to the deposition of wax molecules thereon, and effectively plays a wax prevention role; the viscosity reduction rate is high, indicating that the chemical plugging remover provided by the present application not only has a good heating and dissolving effect on oil well wax, but also has a certain viscosity reduction effect on heavy oil, and can reduce the viscosity of crude oil.

[0049] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A delayed exothermic chemical plugging remover for oil field oil layers, characterized in that: The raw materials include component A, component B and a catalyst; the raw materials in component A include 20-31% ammonium chloride and 69-80% water by mass percentage; the raw materials in component B include 26-40% sodium nitrite, 4-6% solvent oil, 1-2% mixed aromatic hydrocarbons, 1-2% emulsifier, 0.2-1.5% paraffin dispersant, 1-2% mutual solvent, 0.5-1% alkyl sulfonic acid metal salt, and 47.8-64% water by mass percentage; the mass ratio of component A, component B and catalyst is 1:0.9-1.1:0.03-0.1; and the catalyst is potassium dihydrogen phosphate.

2. The delayed exothermic chemical plugging remover for oil field oil layer according to claim 1, characterized in that: The catalyst also includes an auxiliary agent; the auxiliary agent is polyferric sulfate.

3. The delayed exothermic chemical plugging remover for oil field oil layer according to claim 2, characterized in that: The mass ratio of the potassium dihydrogen phosphate to the polyferric sulfate is 1:0.01-0.

07.

4. The delayed exothermic chemical plugging remover for oil field oil layer according to claim 3, characterized in that: The polymerized ferric sulfate is prepared from the following raw materials in parts by weight: 27.9-41.9 parts of ferrous sulfate, 70-105 parts of distilled water, 1.66-2.49 parts of concentrated sulfuric acid, and 5.5-8.3 parts of hydrogen peroxide.

5. The delayed exothermic chemical plugging remover for oil field oil layer according to claim 4, characterized in that: The preparation method of the polyferric sulfate comprises the following steps: Add distilled water to ferrous sulfate, stir until dissolved, then add concentrated sulfuric acid, stir evenly to obtain a mixed solution, heat the mixed solution to 20-30°C in a water bath, drop hydrogen peroxide, and control the dropping time to 30-40min; then heat to 50-60°C, hydrolyze and polymerize for 3-5h, then take out, mature at room temperature for 24-30h to obtain a liquid product, and freeze-dry the liquid product to obtain solid polyferric sulfate.

6. The delayed exothermic chemical plugging remover for oil field oil layer according to claim 1, characterized in that: The mixed aromatic hydrocarbons are composed of benzene, toluene, xylene, trimethylbenzene and ethylbenzene; the mass ratio of benzene, toluene, xylene, trimethylbenzene and ethylbenzene is 3-5:2-3:10-20:2.5-5:2.5-5.

7. The delayed exothermic chemical plugging remover for oil field oil layer according to claim 1, characterized in that: The alkyl sulfonate metal salt is C10-C20 alkyl sulfonate sodium salt.

8. The delayed exothermic chemical plugging remover for oil field oil layer according to claim 1, characterized in that: The emulsifier is a mixture of one or more of Tween, OP-10 and Span.

9. The method for preparing a delayed exothermic chemical plugging remover for oil field oil layers according to any one of claims 1 to 8, characterized in that: The following steps are involved: 20-31% ammonium chloride and 69-80% water are mixed uniformly according to mass percentage to obtain component A; 26-40% sodium nitrite, 4-6% solvent oil, 1-2% mixed aromatic hydrocarbons, 1-2% emulsifier, 0.2-1.5% paraffin dispersant, 1-2% mutual solvent, 0.5-1% alkyl sulfonic acid metal salt, and 47.8-64% water are mixed uniformly according to mass percentage to obtain component B; preparing a catalyst; After mixing component A, component B and the catalyst, a chemical plugging remover with delayed heat release is obtained.

10. The use of a delayed exothermic chemical plugging remover for oil field oil layers according to any one of claims 1 to 8, characterized in that: The chemical plugging remover is used in clearing wax and removing plugging in oil fields.

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