Film-forming filtrate reducer, preparation method thereof, workover fluid and workover method

Abstract

The invention relates to a film-forming filtrate reducer and a preparation method thereof, workover fluid and a workover method, and relates to the field of workover, the film-forming filtrate reducer comprises an oil phase, an emulsifier, acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyl dimethyl allyl ammonium chloride, water and an initiator; the workover fluid comprises water, a tackifier, a plugging agent, an acid-soluble temporary plugging agent, an interface modifier, a corrosion inhibitor, a weighting agent and the film-forming filtrate reducer. According to the film-forming filtrate reducer provided by the invention, specific acrylamide, N-vinyl pyrrolidone, acrylamido-2-methylpropanesulfonic acid and hexadecyl dimethyl allyl ammonium chloride are subjected to reverse emulsion polymerization to obtain a polymer, and the polymer is greatly adsorbed on the surface of a filter cake under the action of high temperature and high pressure to form a high-toughness polymeric film; the filter loss is reduced; the temperature resistance of the workover fluid is larger than or equal to 180 DEG C, the pressure-bearing plugging capacity of the workover fluid to a crack core is larger than 10 MPa, and the permeability recovery value is larger than or equal to 92%.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas well repair, and specifically to a film-forming fluid loss reducer and a preparation method thereof, a well repair fluid, and a well repair method, and especially to a high-temperature and high-pressure film-forming fluid loss reducer and a preparation method thereof, a well repair fluid, and a well repair method. Background Art

[0002] Gas storage facilities have the advantages of large storage capacity, wide peak-shaving range, and high safety factor, and are playing an increasingly important role in the development of the natural gas industry.

[0003] Gas storages are usually converted from depleted oil and gas reservoirs. The reservoir geological conditions are complex, with characteristics such as strong heterogeneity, low reservoir pressure coefficient, and structural fragmentation. The operating pressure difference during the workover process is large, and workover fluid leakage often occurs, which not only greatly increases the amount of workover fluid used, but also easily induces solid phase invasion damage, fluid sensitivity damage, and water phase closure damage, affecting the production after the workover operation, and seriously affecting the injection and production efficiency and economic benefits of the gas storage.

[0004] In recent years, hydrocarbon-based workover fluids, gel-type workover fluids, PRD workover fluids and other systems have been developed at home and abroad.

[0005] For example, CN110305642A discloses an oil and gas well repair working fluid, which is composed of a brine base fluid, a polymer, an oil-soluble resin, sodium iminodisuccinate and a heat-sensitive additive, wherein the mass content of each component is: 0.5-1% polymer, 0.5-1% oil-soluble resin, 0.4-0.8% sodium iminodisuccinate, 0.1-2% heat-sensitive additive, and the brine base fluid is the balance.

[0006] CN104818003A A high-temperature, low-pressure oil and gas well protection reservoir workover fluid belongs to the technical field of oil and gas well protection fluid. It includes the following components, each component is calculated by mass percentage: NaOH 0.3%, Na2CO3 0.2%, suspension stabilizer 3.5%, film-forming plugging agent 8.0%, high-temperature fluid loss reducer 5.0%, high-temperature hydrogel 1.5%, inorganic hydrogel (HIG-a:HIG-b=1:3) 1.0%, KCl 3%, complexing agent HLH-1 5%, and the balance is fresh water.

[0007] However, the existing workover fluids still have defects such as low pressure-bearing and plugging capacity, poor anti-liquid lock effect, and poor self-unplugging ability. They cannot effectively solve the problem of working fluid reservoir damage during the workover process of gas storage reservoirs, bringing great challenges to the workover operations of gas storage reservoirs. Summary of the invention

[0008] In view of the problems existing in the prior art, the purpose of the present invention is to provide a film-forming filtrate reducer and a preparation method thereof, a well repair fluid, and a well repair method, so as to solve the defects of the existing well repair fluid such as low pressure-bearing and plugging capacity, insufficient liquid-proof locking effect, and poor self-unplugging ability.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a film-forming fluid loss reducer, wherein the raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight:

[0011] 120-180 parts of oil phase, 15-20 parts of emulsifier, 20-30 parts of acrylamide, 8-15 parts of N-vinyl pyrrolidone, 20-40 parts of 2-acrylamido-2-methylpropanesulfonic acid, 5-10 parts of hexadecyl dimethyl allyl ammonium chloride, 90-110 parts of water, and 1.5-2 parts of initiator.

[0012] The film-forming fluid loss reducer provided by the present invention is matched with specific acrylamide, N-vinyl pyrrolidone, acrylamido-2-methylpropane sulfonic acid and hexadecyl dimethyl allyl ammonium chloride, so that the obtained film-forming fluid loss reducer contains amide groups, quaternary ammonium cations and sulfonate ions, which are adsorbed on the surface of the filter cake through film-forming adsorption, and are adsorbed in large quantities on the surface of the filter cake under high temperature and high pressure to form a high-molecular film with strong toughness. In addition, various particles in the plugging layer can be bonded together with a chemical film to improve the compactness of the filter cake and reduce the loss of the well repairing fluid to the reservoir.

[0013] As a preferred technical solution of the present invention, the oil phase includes white oil and / or diesel.

[0014] Preferably, the emulsifier comprises one or a combination of at least two of Span-80 emulsifier, Tween 80 or glyceryl monostearate.

[0015] Preferably, the initiator includes one or a combination of at least two of potassium persulfate, ammonium persulfate or azobisisobutyronitrile.

[0016] In a second aspect, the present invention provides a method for preparing the film-forming fluid loss reducer as described in the first aspect, the preparation method comprising:

[0017] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0018] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0019] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added to carry out a polymerization reaction to obtain a film-forming fluid loss reducer.

[0020] As a preferred technical solution of the present invention, the endpoint pH value of the pH adjustment is 6.5-8.5.

[0021] As a preferred technical solution of the present invention, the stirring rate of the stirring emulsification is 6000-7000r / min.

[0022] Preferably, the adding of the initiator is carried out under a protective atmosphere.

[0023] Preferably, the liquid phase temperature of the added initiator is 70-80°C.

[0024] Preferably, the polymerization temperature is 70-80°C.

[0025] Preferably, the polymerization reaction time is 3-4 hours.

[0026] In a third aspect, the present invention provides a self-degradable chemical film protection reservoir repair fluid, the self-degradable chemical film protection reservoir repair fluid comprising:

[0027] Water, thickener, plugging agent, acid-soluble temporary plugging agent, interface modifier, corrosion inhibitor, weighting agent and the aforementioned film-forming fluid loss reducer.

[0028] As a preferred technical solution of the present invention, the self-degradable chemical film protective reservoir workover fluid comprises, by weight:

[0029] 80-120 parts of water, 2-10 parts of thickener, 2-8 parts of plugging agent, 10-40 parts of acid-soluble temporary plugging agent, 0.2-1 parts of interface modifier, 0.5-2 parts of corrosion inhibitor, 10-100 parts of weighting agent and 3-12 parts of film-forming fluid loss reducer as described in the first aspect.

[0030] As a preferred technical solution of the present invention, the thickener includes one or a combination of at least two of hydroxyethyl cellulose, high viscosity polyanionic cellulose HV-PAC or thickener CX-216, preferably a mass ratio of high viscosity polyanionic cellulose HV-PAC and thickener CX-216 of (0.5-2):(1-3), and further preferably a mass ratio of high viscosity polyanionic cellulose HV-PAC and thickener CX-216 of (1-1.1):2.

[0031] Preferably, the plugging agent comprises one of sulfonated asphalt, polymer microsphere plugging agent or nano calcium carbonate, or a combination of at least two thereof, preferably polymer microsphere plugging agent and / or nano calcium carbonate, and further preferably nano calcium carbonate.

[0032] Preferably, the acid-soluble temporary plugging agent comprises one or a combination of at least two of sepiolite fibers, brucite fibers or polylactic acid fibers, preferably sepiolite fibers and / or polylactic acid fibers, and more preferably polylactic acid fibers.

[0033] Preferably, the interface modifier comprises an organic silicon polymer interface modifier.

[0034] Preferably, the corrosion inhibitor comprises an imidazoline-type corrosion inhibitor.

[0035] Preferably, the weighting agent includes one or a combination of at least two of barite powder, formate or organic salt weighting agent Weight2, preferably formate and / or organic salt weighting agent Weight2, and further preferably organic salt weighting agent Weight2.

[0036] As a preferred technical solution of the present invention, the self-degradable chemical film protective reservoir workover fluid comprises, by weight:

[0037] 90-110 parts of water, 4-8 parts of tackifier, 4-8 parts of plugging agent, 10-40 parts of acid-soluble temporary plugging agent, 0.2-0.5 parts of interface modifier, 0.5-1.8 parts of corrosion inhibitor, 30-90 parts of weighting agent and 8-11 parts of film-forming fluid loss reducer;

[0038] Among them, the thickener is a high viscosity polyanionic cellulose HV-PAC and a thickener CX-216 in a mass ratio of (0.5-2):(1-3), the plugging agent is a polymer microsphere plugging agent and / or nano calcium carbonate, the acid-soluble temporary plugging agent includes sepiolite fiber and / or polylactic acid fiber, and the weighting agent includes formate and / or organic salt weighting agent Weight2.

[0039] In a fourth aspect, the present invention provides a well repairing method, the well repairing method comprising: performing well repairing using the self-degradable chemical film protection reservoir repairing fluid as described in the third aspect.

[0040] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0041] (1) The well repair fluid provided by the present invention has a temperature resistance of ≥180°C, a pressure-bearing plugging capacity for fractured cores of ≥8.4 MPa, a plugging rate of ≥91%, and a permeability recovery value of ≥92%, thereby overcoming the dual problems of low pressure-bearing plugging capacity and poor reservoir protection effect. Within the preferred range, the pressure-bearing plugging capacity for fractured cores is >10 MPa, the plugging rate is >94%, and the permeability recovery value is >95%.

[0042] (2) The well repair fluid provided by the present invention adopts a preferred solution by adding polylactic acid fibers of different sizes into the well repair fluid, which can form a stable plugging layer at the opening of the fracture hole, thereby reducing the entry of harmful solid phases in the working fluid into the reservoir. Later in the injection and production process, it can be unblocked by automatic degradation (the degradation rate is close to 100% after 28 days), thereby restoring the flow conductivity of the fracture hole channel and improving the gas production and gas production efficiency of the gas storage.

[0043] (3) In the well repair fluid provided by the present invention, nano calcium carbonate is used as a plugging agent, which can enter micro cracks and micro pores to play a role in strengthening, toughening and filling. The use of organosilicon polymer interface modifiers as waterproof lock agents can significantly improve the waterproof lock ability of the well repair fluid and reduce the damage of water phase closure. The water-soluble organic salt weighting agent Weight2 is used as a weighting agent, which can be completely dissolved in water, overcomes the problems of high solid content and difficult rheological control of conventional weighting materials such as barite, limestone powder, and iron ore powder, and greatly reduces the damage of solid phase invasion. Through the synergistic effect of various treatment agent materials, the well repair fluid and the well wall rock undergo chemical and physical effects, forming a dense and tough plugging layer on the well wall, achieving the purpose of effectively improving the pressure bearing capacity of the formation and preventing harmful solid phases and filtrate in the well repair fluid from entering the reservoir. DETAILED DESCRIPTION

[0044] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0045] This embodiment provides a film-forming fluid loss control agent, and the raw materials for preparing the film-forming fluid loss control agent include the following components in parts by weight:

[0046] 120-180 parts of oil phase, 15-20 parts of emulsifier, 20-30 parts of acrylamide, 8-15 parts of N-vinyl pyrrolidone, 20-40 parts of 2-acrylamido-2-methylpropanesulfonic acid, 5-10 parts of hexadecyl dimethyl allyl ammonium chloride, 90-110 parts of water, and 1.5-2 parts of initiator.

[0047] In the present invention, the oil phase in the film-forming fluid loss reducer is 120-180 parts by weight, for example, it can be 120 parts, 125 parts, 130 parts, 135 parts, 140 parts, 145 parts, 150 parts, 155 parts, 160 parts, 165 parts, 170 parts, 175 parts or 180 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0048] In the present invention, the emulsifier in the film-forming fluid loss reducer is 15-20 parts by weight, for example, it can be 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0049] In the present invention, the acrylamide in the film-forming fluid loss reducer is 20-30 parts by weight, for example, it can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts or 30 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0050] In the present invention, the N-vinyl pyrrolidone in the film-forming fluid loss reducer is 8-15 parts by weight, for example, it can be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts or 15 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0051] In the present invention, the 2-acrylamido-2-methylpropane sulfonic acid in the film-forming fluid loss reducer is 20-40 parts by weight, for example, it can be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts or 40 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0052] In the present invention, the hexadecyl dimethyl allyl ammonium chloride in the film-forming fluid loss reducer is 5-10 parts by weight, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0053] In the present invention, the water in the film-forming fluid loss reducer is 90-110 parts by weight, for example, it can be 90 parts, 92 parts, 94 parts, 96 parts, 98 parts, 100 parts, 102 parts, 104 parts, 106 parts, 108 parts or 110 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0054] In the present invention, the initiator in the film-forming fluid loss reducer is 1.5-2 parts by weight, for example, it can be 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts or 2 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0055] Wherein, the oil phase includes white oil and / or diesel.

[0056] Wherein, the emulsifier includes one or a combination of at least two of Span-80 emulsifier, Tween 80 or glyceryl monostearate.

[0057] Wherein, the initiator includes one or a combination of at least two of potassium persulfate, ammonium persulfate or azobisisobutyronitrile.

[0058] Furthermore, the present invention provides a method for preparing the aforementioned film-forming fluid loss reducer, the preparation method comprising:

[0059] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0060] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0061] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added to carry out a polymerization reaction to obtain a film-forming fluid loss reducer.

[0062] The end point pH value of the pH adjustment is 6.5-8.5, for example, it can be 6.5, 7.0, 7.5, 8 or 8.5, but is not limited to the listed values, and other values ​​not listed in the range also meet the requirements.

[0063] Wherein, the stirring rate of the stirring emulsification is 6000-7000r / min, for example, it can be 6000r / min, 6200r / min, 6400r / min, 6600r / min, 6800r / min or 7000r / min, but is not limited to the listed values, and other unlisted values ​​within the range also meet the requirements.

[0064] Wherein, the adding of the initiator is carried out under a protective atmosphere.

[0065] In the present invention, the protective atmosphere includes at least one of nitrogen, helium, neon, argon and the like.

[0066] The liquid phase temperature of the added initiator is 70-80°C, for example, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0067] The polymerization reaction temperature is 70-80°C, for example, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0068] The polymerization reaction time is 3-4 hours, for example, 3.0 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours or 4.0 hours, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0069] Furthermore, the present invention provides a self-degradable chemical film protection reservoir repair fluid, the self-degradable chemical film protection reservoir repair fluid comprising:

[0070] Water, thickener, plugging agent, acid-soluble temporary plugging agent, interface modifier, corrosion inhibitor, weighting agent and the aforementioned film-forming fluid loss reducer.

[0071] Wherein, the self-degradable chemical film protection reservoir workover fluid comprises, by weight:

[0072] 80-120 parts of water, 2-10 parts of thickener, 2-8 parts of plugging agent, 10-40 parts of acid-soluble temporary plugging agent, 0.2-1 parts of interface modifier, 0.5-2 parts of corrosion inhibitor, 10-100 parts of weighting agent and 3-12 parts of the aforementioned film-forming fluid loss reducer.

[0073] In the present invention, the water content in the self-degradable chemical film protection reservoir workover fluid is 80-120 parts by weight, for example, it can be 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, 90 parts, 92 parts, 94 parts, 96 parts, 98 parts, 100 parts, 102 parts, 104 parts, 106 parts, 108 parts, 110 parts, 112 parts, 114 parts, 116 parts, 118 parts or 120 parts, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0074] In the present invention, the viscosity enhancer in the self-degradable chemical film protection reservoir workover fluid is 2-10 parts by weight, for example, it can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0075] In the present invention, the plugging agent in the self-degradable chemical film protection reservoir workover fluid is 2-8 parts by weight, for example, it can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts or 8 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0076] In the present invention, the acid-soluble temporary plugging agent in the self-degradable chemical film protective reservoir workover fluid is 10-40 parts by weight, for example, it can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts or 40 parts, but is not limited to the listed values, and other values ​​not listed within this range also meet the requirements.

[0077] In the present invention, the interface modifier in the self-degradable chemical film protective reservoir workover fluid is 0.2-1 parts by weight, for example, it can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts or 1 parts, but is not limited to the listed values, and other values ​​not listed within this range also meet the requirements.

[0078] In the present invention, the corrosion inhibitor in the self-degradable chemical film protective reservoir workover fluid is 0.5-2 parts by weight, for example, it can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts or 2 parts, but is not limited to the listed values, and other values ​​not listed within this range also meet the requirements.

[0079] In the present invention, the weighting agent in the self-degradable chemical film protective reservoir workover fluid is 10-100 parts by weight, for example, it can be 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts or 100 parts, but is not limited to the listed values, and other unlisted values ​​within this range also meet the requirements.

[0080] In the present invention, the film-forming fluid loss reducer in the self-degradable chemical film protection reservoir workover fluid is 3-12 parts by weight, for example, it can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts or 12 parts, but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0081] Wherein, the viscosity enhancer includes one or a combination of at least two of hydroxyethyl cellulose, high viscosity polyanionic cellulose HV-PAC or viscosity enhancer CX-216.

[0082] Wherein, the plugging agent includes one or a combination of at least two of sulfonated asphalt, polymer microsphere plugging agent or nano calcium carbonate.

[0083] Exemplarily, the sulfonated asphalt used is a sulfonated asphalt that complies with the SY / T 5665-2018 standard for modified asphalt of anti-collapse plugging agent for drilling fluid, such as FT-1A.

[0084] Exemplarily, the polymer microsphere plugging agent used is a microsphere that complies with the Q / SY CPET J120051-2022 standard, such as ISP-1.

[0085] Exemplarily, the particle size of the nano calcium carbonate used is D 90 <90nm.

[0086] Wherein, the acid-soluble temporary plugging agent includes one of sepiolite fiber, brucite fiber or polylactic acid fiber or a combination of at least two thereof.

[0087] Exemplarily, the length of the sepiolite fibers used is 2-5 mm.

[0088] Exemplarily, the length of the brucite fibers used is 2-5 mm.

[0089] Exemplarily, the length of the polylactic acid fiber used is ≤5mm, and preferably the mass ratio of polylactic acid fiber A (3≤A≤5mm), polylactic acid fiber B (1≤B<3mm), polylactic acid fiber (<1mm) is (1.8-2.1):(2.8-3.2):(1.8-2.2).

[0090] Wherein, the interface modifier includes an organic silicon polymer interface modifier.

[0091] For example, the organic silicon polymer interface modifier used includes silane coupling agent KH-560 and other organic silicon polymer interface modifiers commonly used in the art.

[0092] Wherein, the corrosion inhibitor includes an imidazoline-type corrosion inhibitor.

[0093] Illustratively, the imidazoline corrosion inhibitor used includes imidazoline corrosion inhibitor KLSS-A and other imidazoline corrosion inhibitors commonly used in the art.

[0094] Wherein, the weighting agent includes one or a combination of at least two of barite powder, formate or organic salt weighting agent Weight2;

[0095] Wherein, the self-degradable chemical film protection reservoir workover fluid comprises, by weight:

[0096] 90-110 parts of water, 4-8 parts of thickener, 4-8 parts of plugging agent, 10-40 parts of acid-soluble temporary plugging agent, 0.2-0.5 parts of interface modifier, 0.5-1.8 parts of corrosion inhibitor, 30-90 parts of weighting agent and 8-11 parts of the aforementioned film-forming fluid loss reducer;

[0097] Among them, the thickener is a high viscosity polyanionic cellulose HV-PAC and a thickener CX-216 in a mass ratio of (0.5-2):(1-3), the plugging agent is a polymer microsphere plugging agent and / or nano calcium carbonate, the acid-soluble temporary plugging agent includes sepiolite fiber and / or polylactic acid fiber, and the weighting agent includes formate and / or organic salt weighting agent Weight2.

[0098] Wherein, the self-degradable chemical film protection reservoir workover fluid comprises, by weight:

[0099] 98-100 parts of water, 5-6 parts of tackifier, 6-8 parts of plugging agent, 30-36 parts of acid-soluble temporary plugging agent, 0.3-0.5 parts of interface modifier, 0.6-1.4 parts of corrosion inhibitor, 40-60 parts of weighting agent and 8-10 parts of the aforementioned film-forming fluid loss reducer;

[0100] Among them, the thickener includes high viscosity polyanionic cellulose HV-PAC and thickener CX-216 in a mass ratio of (1-1.1):2; the plugging agent is nano calcium carbonate; the acid-soluble temporary plugging agent is polylactic acid fiber; and the weighting agent is an organic salt weighting agent Weight2.

[0101] In the present invention, the self-degradable chemical film protection reservoir repair fluid is obtained by mixing ingredients according to a weight ratio.

[0102] Furthermore, the present embodiment provides a well repairing method, which comprises: using the aforementioned self-degradable chemical film protection reservoir repairing fluid to perform well repairing.

[0103] Further, in order to illustrate the advantages that the present invention can provide by providing a film-forming fluid loss reducer and a self-degradable chemical film to protect a reservoir workover fluid, the following actual examples are used for exemplary description, as follows:

[0104] Example 1

[0105] This embodiment provides a film-forming fluid loss reducer, which is as follows:

[0106] The raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight:

[0107] 150 parts of oil phase, 17 parts of emulsifier, 24 parts of acrylamide, 11 parts of N-vinyl pyrrolidone, 30 parts of 2-acrylamido-2-methylpropanesulfonic acid, 7 parts of hexadecyl dimethyl allyl ammonium chloride, 100 parts of water, and 1.7 parts of initiator;

[0108] The oil phase is white oil; the emulsifier is Span-80 emulsifier; the initiator is potassium persulfate;

[0109] The preparation process of film-forming fluid loss additive is as follows:

[0110] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0111] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0112] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added for polymerization reaction to obtain a film-forming fluid loss reducer;

[0113] Wherein, the endpoint pH value of the pH adjustment is 7;

[0114] The stirring rate of the stirring emulsification is 6000 r / min; the adding of the initiator is carried out under a protective atmosphere; the liquid phase temperature of the added initiator is 75° C.; the temperature of the polymerization reaction is 75° C.; and the time of the polymerization reaction is 3.5 h.

[0115] Example 2

[0116] This embodiment provides a film-forming fluid loss reducer, which is as follows:

[0117] The raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight:

[0118] 155 parts of oil phase, 17.5 parts of emulsifier, 25 parts of acrylamide, 12 parts of N-vinyl pyrrolidone, 32 parts of 2-acrylamido-2-methylpropanesulfonic acid, 7.5 parts of hexadecyl dimethyl allyl ammonium chloride, 100 parts of water, and 1.7 parts of initiator;

[0119] The oil phase is white oil; the emulsifier is Tween 80 emulsifier; the initiator is ammonium persulfate;

[0120] The preparation process of film-forming fluid loss additive is as follows:

[0121] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0122] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0123] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added for polymerization reaction to obtain a film-forming fluid loss reducer;

[0124] Wherein, the endpoint pH value of the pH adjustment is 7;

[0125] The stirring rate of the stirring emulsification is 6500 r / min; the adding of the initiator is carried out under a protective atmosphere; the liquid phase temperature of the added initiator is 76° C.; the temperature of the polymerization reaction is 76° C.; and the time of the polymerization reaction is 3.6 h.

[0126] Example 3

[0127] This embodiment provides a film-forming fluid loss reducer, which is as follows:

[0128] The raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight:

[0129] 140 parts of oil phase, 16 parts of emulsifier, 22 parts of acrylamide, 10 parts of N-vinyl pyrrolidone, 25 parts of 2-acrylamido-2-methylpropanesulfonic acid, 8 parts of hexadecyl dimethyl allyl ammonium chloride, 98 parts of water, 1.6 parts of initiator;

[0130] The oil phase is white oil; the emulsifier is glyceryl monostearate; the initiator is azobisisobutyronitrile;

[0131] The preparation process of film-forming fluid loss additive is as follows:

[0132] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0133] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0134] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added for polymerization reaction to obtain a film-forming fluid loss reducer;

[0135] Wherein, the endpoint pH value of the pH adjustment is 8.5;

[0136] The stirring rate of the stirring emulsification is 6500 r / min; the adding of the initiator is carried out under a protective atmosphere; the liquid phase temperature of the added initiator is 72° C.; the temperature of the polymerization reaction is 72° C.; and the time of the polymerization reaction is 3.8 h.

[0137] Example 4

[0138] This embodiment provides a film-forming fluid loss reducer, which is as follows:

[0139] The raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight:

[0140] 160 parts of oil phase, 18 parts of emulsifier, 27 parts of acrylamide, 13 parts of N-vinyl pyrrolidone, 35 parts of 2-acrylamido-2-methylpropanesulfonic acid, 6 parts of hexadecyl dimethyl allyl ammonium chloride, 105 parts of water, and 1.8 parts of initiator;

[0141] The oil phase is white oil; the emulsifier is Span-80 emulsifier; the initiator is potassium persulfate;

[0142] The preparation process of film-forming fluid loss additive is as follows:

[0143] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0144] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0145] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added for polymerization reaction to obtain a film-forming fluid loss reducer;

[0146] Wherein, the endpoint pH value of the pH adjustment is 7.5;

[0147] The stirring rate of the stirring emulsification is 6800 r / min; the adding of the initiator is carried out under a protective atmosphere; the liquid phase temperature of the added initiator is 78° C.; the temperature of the polymerization reaction is 78° C.; and the time of the polymerization reaction is 3.2 h.

[0148] Example 5

[0149] This embodiment provides a film-forming fluid loss reducer, which is as follows:

[0150] The raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight:

[0151] 180 parts of oil phase, 15 parts of emulsifier, 30 parts of acrylamide, 8 parts of N-vinyl pyrrolidone, 40 parts of 2-acrylamido-2-methylpropanesulfonic acid, 10 parts of hexadecyl dimethyl allyl ammonium chloride, 90 parts of water, and 1.5 parts of initiator;

[0152] The oil phase is white oil; the emulsifier is Span-80 emulsifier; the initiator is potassium persulfate;

[0153] The preparation process of film-forming fluid loss additive is as follows:

[0154] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0155] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0156] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added for polymerization reaction to obtain a film-forming fluid loss reducer;

[0157] Wherein, the endpoint pH value of the pH adjustment is 8.0;

[0158] The stirring rate of the stirring emulsification is 7000 r / min; the addition of the initiator is carried out under a protective atmosphere (nitrogen); the liquid phase temperature of the added initiator is 80° C.; the temperature of the polymerization reaction is 80° C.; and the time of the polymerization reaction is 3 hours.

[0159] Example 6

[0160] This embodiment provides a film-forming fluid loss reducer, which is as follows:

[0161] The raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight:

[0162] 120 parts of oil phase, 20 parts of emulsifier, 20 parts of acrylamide, 15 parts of N-vinyl pyrrolidone, 20 parts of 2-acrylamido-2-methylpropanesulfonic acid, 5 parts of hexadecyl dimethyl allyl ammonium chloride, 110 parts of water, 2 parts of initiator;

[0163] The oil phase is white oil; the emulsifier includes glyceryl monostearate; the initiator is potassium persulfate;

[0164] The preparation process of film-forming fluid loss additive is as follows:

[0165] mixing the oil phase and the emulsifier to obtain an oil phase solution;

[0166] acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution;

[0167] The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added for polymerization reaction to obtain a film-forming fluid loss reducer;

[0168] Wherein, the endpoint pH value of the pH adjustment is 6.5;

[0169] The stirring rate of the stirring emulsification is 6000 r / min; the addition of the initiator is carried out under a protective atmosphere (argon); the liquid phase temperature of the added initiator is 70° C.; the temperature of the polymerization reaction is 70° C.; and the polymerization reaction time is 4 hours.

[0170] Example 7

[0171] The only difference from Example 1 is that hexadecyldimethylallylammonium chloride is replaced by an equal amount of dimethyldiallylammonium chloride.

[0172] Example 8

[0173] The only difference from Example 1 is that the weight portion of acrylamide in the film-forming fluid loss reducer is 50 parts.

[0174] Example 9

[0175] The only difference from Example 1 is that N-vinyl pyrrolidone is replaced by an equal amount of propenyl pyrrolidone.

[0176] The film-forming fluid loss reducer obtained in Example 1-9 was added to the base slurry (by mass percentage, bentonite 2%, high viscosity polyanionic cellulose HV-PA 3.0%, and organic salt weighting agent Weight2 was used to control the density to 1.60 g / cm 3 , the solvent is water), and the rheological properties are tested. The mass of the film-forming fluid loss reducer is 3% of the weight of the base slurry. The rheological properties are measured according to the method specified in the national standard GB / T16783.1-2014. The effects of Examples 1-9 on the rheological properties of the base slurry are shown in Table 1.

[0177] Table 1

[0178]

[0179] Application Example 1

[0180] The film-forming fluid loss reducer obtained in Example 1 was used as a component of a self-degradable chemical film protection reservoir workover fluid, specifically as follows:

[0181] In parts by weight, 100 parts of water, 5 parts of thickener (high viscosity polyanionic cellulose HV-PAC and thickener CX-216 in a mass ratio of 1:2), 10 parts of film-forming fluid loss reducer, and 6 parts of plugging agent (nano calcium carbonate, D 90 50nm), 30 parts of acid-soluble temporary plugging agent (polylactic acid fiber A (3≤A≤5mm), polylactic acid fiber B (1≤B<3mm), polylactic acid fiber (<1mm) with a mass ratio of 2:3:2), 0.3 parts of interface modifier (KH-560), 0.6 parts of corrosion inhibitor (imidazoline corrosion inhibitor KLSS-A), 60 parts of weighting agent (organic salt weighting agent Weight2) were mixed in a stirrer and stirred at room temperature of 25℃ for 1h to obtain a density of 1.58g / cm 3 Self-degradable chemical film to protect reservoir workover fluid.

[0182] Application Example 2

[0183] The film-forming fluid loss reducer obtained in Example 2 was used as a component of a self-degradable chemical film protection reservoir workover fluid, specifically as follows:

[0184] In parts by weight, 100 parts of water, 6 parts of thickener (high viscosity polyanionic cellulose HV-PAC and thickener CX-216 in a mass ratio of 1.1:2), 8 parts of film-forming fluid loss reducer, 8 parts of plugging agent (nano calcium carbonate D 90=70nm), 36 parts of acid-soluble temporary plugging agent (polylactic acid fiber A (3≤A≤5mm), polylactic acid fiber B (1≤B<3mm), polylactic acid fiber (<1mm) with a mass ratio of 1.8:3.2:1.8), 0.5 parts of interface modifier (silane coupling agent KH-560), 1.4 parts of corrosion inhibitor (imidazoline corrosion inhibitor KLSS-A), 40 parts of weighting agent (organic salt weighting agent Weight2) were mixed in a stirrer and stirred at room temperature at 25°C for 1h to obtain a density of 1.39g / cm 3 Self-degradable chemical film to protect reservoir workover fluid.

[0185] Application Example 3

[0186] The film-forming fluid loss reducer obtained in Example 3 was used as a component of a self-degradable chemical film protection reservoir workover fluid, specifically as follows:

[0187] In parts by weight, 80 parts of water, 6 parts of thickener (high viscosity polyanionic cellulose HV-PAC and thickener CX-216 with a mass ratio of 0.5:3), 3 parts of film-forming fluid loss reducer, 8 parts of plugging agent (polymer microsphere plugging agent IPS-1), 28 parts of acid-soluble temporary plugging agent (sepiolite fiber, length 2-5 mm), 0.6 parts of interface modifier (silane coupling agent KH-560), 1.0 parts of corrosion inhibitor (imidazoline corrosion inhibitor KLSS-A), and 20 parts of weighting agent (potassium formate) were mixed in a stirrer and stirred at room temperature at 25°C for 1 hour to prepare a solution with a density of 1.26 g / cm 3 Self-degradable chemical film to protect reservoir workover fluid.

[0188] Application Example 4

[0189] The film-forming fluid loss reducer obtained in Example 4 was used as a component of a self-degradable chemical film protection reservoir workover fluid, specifically as follows:

[0190] In parts by weight, 120 parts of water, 4 parts of thickener (high viscosity polyanionic cellulose HV-PAC and thickener CX-216 in a mass ratio of 2:1), 10 parts of film-forming fluid loss reducer, 2 parts of plugging agent (polymer microsphere plugging agent ISP-1), 16 parts of acid-soluble temporary plugging agent (sepiolite fiber, length 2-5 mm), 0.3 parts of interface modifier (silane coupling agent KH-560), 0.9 parts of corrosion inhibitor (imidazoline corrosion inhibitor KLSS-A), 90 parts of weighting agent (sodium formate) were mixed in a stirrer and stirred at room temperature at 25°C for 1 hour to prepare a solution with a density of 2.09 g / cm 3 Self-degradable chemical film to protect reservoir workover fluid.

[0191] Application Example 5

[0192] The film-forming fluid loss reducer obtained in Example 5 was used as a component of a self-degradable chemical film protection reservoir workover fluid, specifically as follows:

[0193] In parts by weight, 80 parts of water, 5 parts of viscosity enhancer (hydroxyethyl cellulose), 4 parts of film-forming fluid loss reducer, 7 parts of plugging agent (sulfonated asphalt FT-1A), 40 parts of acid-soluble temporary plugging agent (brucite fiber, length of 2-5 mm), 1.0 part of interface modifier (silane coupling agent KH-560), 0.9 part of corrosion inhibitor (imidazoline corrosion inhibitor KLSS-A), 100 parts of weighting agent (barite powder) were mixed in a stirrer and stirred at room temperature of 25°C for 1 hour to prepare a density of 2.56 g / cm 3 Self-degradable chemical film to protect reservoir workover fluid.

[0194] Application Example 6

[0195] The film-forming fluid loss reducer obtained in Example 6 was used as a component of a self-degradable chemical film protection reservoir workover fluid, specifically as follows:

[0196] In parts by weight, 110 parts of water, 3 parts of viscosity enhancer (hydroxyethyl cellulose), 5 parts of film-forming fluid loss reducer, 4 parts of plugging agent (sulfonated asphalt FT-1A), 18 parts of acid-soluble temporary plugging agent (brucite fiber, length 2-5 mm), 0.7 parts of interface modifier (silane coupling agent KH-560), 0.8 parts of corrosion inhibitor (imidazoline corrosion inhibitor KLSS-A), 10 parts of weighting agent (barite powder) were mixed in a stirrer and stirred at room temperature at 25 ° C for 1 hour to prepare a density of 1.03 g / cm 3 Self-degradable chemical film to protect reservoir workover fluid.

[0197] Application Example 7

[0198] The only difference from Application Example 1 is that the film-forming fluid loss reducer obtained in Example 7 is used as a component of the self-degradable chemical film protection reservoir workover fluid.

[0199] Application Example 8

[0200] The only difference from Application Example 1 is that the film-forming fluid loss reducer obtained in Example 8 is used as a component of the self-degradable chemical film protection reservoir workover fluid.

[0201] Application Example 9

[0202] The only difference from Application Example 1 is that the film-forming fluid loss reducer obtained in Example 9 is used as a component of the self-degradable chemical film protection reservoir workover fluid.

[0203] The self-degradable chemical film protection reservoir workover fluid obtained in the application example was subjected to the following performance tests:

[0204] 1. Rheological properties test

[0205] The rheological properties of the self-degradable chemical film protection reservoir workover fluid were measured according to the method specified in the national standard GB / T 16783.1-2014. The rheological properties of each test object are shown in Table 2.

[0206] Table 2

[0207]

[0208]

[0209] As shown in Table 2, the self-degradable chemical film protection reservoir workover fluid provided by Application Examples 1-6 has good rheological properties before and after hot rolling at 180°C for 16 hours, low API filtration loss (<5mL), low HTHP filtration loss (<15mL), and a density range of 1.00-2.60 g / cm 3 Internally adjustable, it can meet the needs of well repair in complex geological conditions.

[0210] 2. Pressure-bearing and plugging capacity test

[0211] The pressure-bearing plugging capacity is measured according to the method specified in the industry standard SY / T 5840-2007 "Indoor Test Method for Bridging Plugging Materials for Drilling Fluids". A high-temperature and high-pressure dynamic plugging simulation experiment is carried out using a self-degradable chemical film to protect the reservoir workover fluid. A positive plugging experiment is carried out on the test modules with seam widths of 1mm, 2mm, and 4mm. The final pressure displayed is the pressure-bearing plugging capacity. The test results of the maximum pressure-bearing plugging capacity corresponding to each embodiment are shown in Table 3.

[0212] Table 3

[0213]

[0214]

[0215] The test results in Table 3 show that the self-degradable chemical film protected reservoir workover fluid provided in Application Examples 1-6 can form a tight sealing plugging layer in the 1mm, 2mm, and 4mm seam plate simulated leaky layers, and its maximum pressure-bearing plugging pressure can reach more than 10MPa. The pressure-bearing plugging capacity of Application Example 1 is the highest, reaching 16.8MPa, indicating that the self-degradable chemical film protected reservoir workover fluid has a high pressure-bearing plugging capacity, and is expected to solve the technical problem of low pressure-bearing capacity of traditional workover fluids.

[0216] 3. Indoor evaluation of reservoir damage

[0217] At a high temperature of 180°C and a pressure of 3.5 MPa, in accordance with the industry standard SY / T 6540-2021 “Indoor Evaluation Method for Damage to Reservoirs by Drilling and Completion Fluids”, an indoor evaluation experiment on reservoir damage was carried out on the above-mentioned workover fluid in a JHDS-2 high-temperature and high-pressure dynamic filter loss instrument. The experimental results are shown in Table 4.

[0218] Table 4

[0219] Well repair fluid Rock Core Gas permeability (mD) Blockage rate (%) Permeability recovery value (%) Application Example 1 F2-6-3 416.93 98.1 96.2 Application Example 2 F2-6-6 232.12 94.6 95.6 Application Example 3 F2-6-1 328.68 91.3 93.3 Application Example 4 F2-6-2 218.15 93.7 92.0 Application Example 5 F2-6-4 239.91 91.1 90.7 Application Example 6 F2-6-5 323.14 90.8 91.8 Application Example 7 F2-6-7 460.31 90.0 93.2 Application Example 8 F2-6-8 350.66 93.9 92.9 Application Example 9 F2-6-9 298.18 92.3 94.2

[0220] It can be seen from Table 4 that the plugging rate of the self-degradable chemical film protection reservoir workover fluid provided by the present invention for medium and high permeability cores is ≥91%, and the plugging efficiency of Application Examples 1 and 2 is the best. After being contaminated by the self-degradable chemical film protection reservoir workover fluid provided by the present invention, the permeability recovery value of the core is ≥92%, and the highest reaches 96.2%, indicating that the self-degradable chemical film protection reservoir workover fluid system provided by the present invention can play a good reservoir protection effect.

[0221] Through the above tests, it can be known that the self-degradable chemical film protection reservoir repair fluid provided by the present invention has the characteristics of strong high temperature resistance, high pressure bearing and sealing ability, good reservoir protection effect, etc. It can solve the dual problems of low reservoir pressure bearing capacity and poor reservoir protection effect that restrict the repair operation process of gas storage reservoirs, meet the needs of repair projects under complex geological conditions, and realize safe and efficient repair operations.

[0222] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0223] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0224] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A film-forming fluid loss reducer, characterized in that: The raw materials for preparing the film-forming fluid loss reducer include the following components in parts by weight: 120-180 parts of oil phase, 15-20 parts of emulsifier, 20-30 parts of acrylamide, 8-15 parts of N-vinyl pyrrolidone, 20-40 parts of 2-acrylamido-2-methylpropanesulfonic acid, 5-10 parts of hexadecyl dimethyl allyl ammonium chloride, 90-110 parts of water, and 1.5-2 parts of initiator.

2. The film-forming fluid loss reducer according to claim 1, characterized in that: The oil phase includes white oil and / or diesel; Preferably, the emulsifier comprises one or a combination of at least two of Span-80 emulsifier, Tween 80 or glyceryl monostearate; Preferably, the initiator includes one or a combination of at least two of potassium persulfate, ammonium persulfate or azobisisobutyronitrile.

3. A method for preparing the film-forming fluid loss reducer according to claim 1 or 2, characterized in that: The preparation method comprises: mixing the oil phase and the emulsifier to obtain an oil phase solution; acrylamide, N-vinyl pyrrolidone, 2-acrylamido-2-methylpropanesulfonic acid, hexadecyldimethylallylammonium chloride and water are mixed, and then the pH value is adjusted to obtain an aqueous phase solution; The aqueous phase solution is added dropwise to the oil phase solution for stirring and emulsification, and then an initiator is added to carry out polymerization reaction to obtain a film-forming fluid loss reducer.

4. The preparation method according to claim 3, characterized in that: The end point pH value of the pH adjustment is 6.5-8.

5.

5. The preparation method according to claim 3 or 4, characterized in that: The stirring rate of the stirring emulsification is 6000-7000r / min; Preferably, the adding of the initiator is carried out under a protective atmosphere; Preferably, the liquid phase temperature of the added initiator is 70-80°C; Preferably, the polymerization temperature is 70-80°C; Preferably, the polymerization reaction time is 3-4 hours.

6. A self-degradable chemical film protection reservoir workover fluid, characterized in that: The self-degradable chemical film protection reservoir workover fluid comprises: Water, a viscosity enhancer, a plugging agent, an acid-soluble temporary plugging agent, an interface modifier, a corrosion inhibitor, a weighting agent and the film-forming fluid loss reducer as claimed in claim 1 or 2.

7. The self-degradable chemical film protection reservoir workover fluid according to claim 6, characterized in that: The self-degradable chemical film reservoir protection workover fluid comprises, by weight: 80-120 parts of water, 2-10 parts of thickener, 2-8 parts of plugging agent, 10-40 parts of acid-soluble temporary plugging agent, 0.2-1 parts of interface modifier, 0.5-2 parts of corrosion inhibitor, 10-100 parts of weighting agent and 3-12 parts of film-forming fluid loss reducer.

8. The self-degradable chemical film protective reservoir workover fluid according to claim 6 or 7, characterized in that: The thickener comprises one or a combination of at least two of hydroxyethyl cellulose, high viscosity polyanionic cellulose HV-PAC or thickener CX-216, preferably a mass ratio of high viscosity polyanionic cellulose HV-PAC to thickener CX-216 of (0.5-2):(1-3), and more preferably a mass ratio of high viscosity polyanionic cellulose HV-PAC to thickener CX-216 of (1-1.1):2; Preferably, the plugging agent comprises one or a combination of at least two of sulfonated asphalt, polymer microsphere plugging agent or nano calcium carbonate, preferably polymer microsphere plugging agent and / or nano calcium carbonate, further preferably nano calcium carbonate; Preferably, the acid-soluble temporary plugging agent comprises one or a combination of at least two of sepiolite fiber, brucite fiber or polylactic acid fiber, preferably sepiolite fiber and / or polylactic acid fiber, and more preferably polylactic acid fiber with a length A of 3≤A≤5mm, polylactic acid fiber with a length B of 1≤B<3mm and polylactic acid fiber with a length <1mm in a mass ratio of (1.8-2.1):(2.8-3.2):(1.8-2.2); Preferably, the interface modifier comprises an organic silicon polymer interface modifier; Preferably, the corrosion inhibitor comprises an imidazoline-type corrosion inhibitor; Preferably, the weighting agent includes one or a combination of at least two of barite powder, formate or organic salt weighting agent Weight2, preferably formate and / or organic salt weighting agent Weight2, and further preferably organic salt weighting agent Weight2.

9. The self-degradable chemical film protective reservoir workover fluid according to any one of claims 6 to 8, characterized in that: The self-degradable chemical film reservoir protection workover fluid comprises, by weight: 90-110 parts of water, 4-8 parts of tackifier, 4-8 parts of plugging agent, 10-40 parts of acid-soluble temporary plugging agent, 0.2-0.5 parts of interface modifier, 0.5-1.8 parts of corrosion inhibitor, 30-90 parts of weighting agent and 8-11 parts of film-forming fluid loss reducer; Among them, the thickener is a high viscosity polyanionic cellulose HV-PAC and a thickener CX-216 in a mass ratio of (0.5-2):(1-3), the plugging agent is a polymer microsphere plugging agent and / or nano calcium carbonate, the acid-soluble temporary plugging agent includes sepiolite fiber and / or polylactic acid fiber, and the weighting agent includes formate and / or organic salt weighting agent Weight2.

10. A well repair method, characterized in that: The well repairing method comprises: using the self-degradable chemical film protection reservoir repairing fluid as described in any one of claims 6 to 9 to repair the well.

Images