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CN-121991293-A - Semi-interpenetrating network polymer plugging agent for drilling fluid, and preparation method and application thereof

CN121991293ACN 121991293 ACN121991293 ACN 121991293ACN-121991293-A

Abstract

The invention provides a semi-interpenetrating network polymer plugging agent for drilling fluid, and a preparation method and application thereof, wherein the preparation method comprises the steps of 1) mixing an oil-soluble monomer A and an oil-soluble polymer B, wherein the oil-soluble polymer B is completely dissolved to obtain an oil phase, 2) mixing an emulsifier A, an emulsifier B, a water-soluble organic monomer C and water to obtain a water phase, 3) mixing 65% -70% of the oil phase and the water phase, emulsifying to obtain an emulsion reaction mixed solution, 4) carrying out heat preservation polymerization on the emulsion reaction mixed solution and a first-stage initiator to obtain a polymerized emulsion, and 5) carrying out heat preservation polymerization on the polymerized emulsion, 30% -35% of the residual oil phase, a cross-linking agent and a second-stage initiator to obtain the semi-interpenetrating network polymer plugging agent. The plugging agent can be used for plugging high-temperature stratum, has the advantages of temperature resistance, elastic deformability and cohesiveness, the temperature resistance reaches 180 ℃, the compatibility with oil-based drilling fluid and water-based drilling fluid is good, the filtration reducing and plugging effects are obvious, and the plugging agent can be used for plugging high-temperature stratum and also has the function of cementing and protecting walls.

Inventors

  • ZHANG XIANMIN
  • HU XIAOYAN
  • HUANG NING
  • HAO JISHUANG
  • GUI FANG
  • FAN PENGFEI

Assignees

  • 中石化石油工程技术服务股份有限公司
  • 中石化中原石油工程有限公司
  • 中石化中原石油工程有限公司钻井工程技术研究院

Dates

Publication Date
20260508
Application Date
20241106

Claims (10)

  1. 1. A preparation method of a semi-interpenetrating network polymer plugging agent for drilling fluid comprises the following steps: 1) Mixing an oil-soluble monomer A and an oil-soluble polymer B, wherein the oil-soluble polymer B is completely dissolved to obtain an oil phase; 2) Mixing an emulsifier A, an emulsifier B, a water-soluble organic monomer C and water to obtain a water phase; 3) Mixing 65% -70% of oil phase and water phase, and emulsifying to obtain an emulsion reaction mixed solution; 4) Carrying out heat preservation polymerization on the emulsion reaction mixed solution and a first-stage initiator to obtain emulsion after polymerization; 5) And continuing to perform heat preservation polymerization on the emulsion after polymerization, 30% -35% of residual oil phase, a cross-linking agent and a two-stage initiator solution to obtain the semi-interpenetrating network polymer plugging agent.
  2. 2. The preparation method according to claim 1, wherein the oil-soluble monomer A in the step 1) is one or more selected from butyl methacrylate, methyl acrylate, vinyl acetate, butyl acrylate and isooctyl acrylate; The oil-soluble polymer B is one or more selected from polystyrene, styrene-acrylic ester copolymer, polymethyl methacrylate, acrylic ester homopolymer, acrylic ester copolymer and styrene-butadiene rubber.
  3. 3. The preparation method according to claim 1, wherein the emulsifier a in step 2) is selected from one or more of sodium alkyl sulfate, sodium alkyl benzene sulfonate, sodium dialkyl-2-sulfosuccinate and sodium alkyl allyloxy polyoxyethylene phosphate; The emulsifier B is one or more selected from polyoxyethylene alkyl ether, polyoxyethylene phenol ether, polyoxyethylene sorbitan ether stearate and polyoxyethylene sorbitan monooleate; the water-soluble organic monomer C is selected from one or more of methacrylic acid, acrylamide, acrylic acid and AMPS.
  4. 4. The method of claim 1, wherein the cross-linking agent is selected from one or more of N, N' -methylenebisacrylamide, polyvinyl alcohol diacrylate, 1, 3-butadiene, and 1, 4-divinylbenzene.
  5. 5. The method of claim 1, wherein the primary initiator and the secondary initiator are independently selected from one or more of sodium persulfate, potassium persulfate, and ammonium persulfate.
  6. 6. The preparation method according to claim 1, wherein the water-soluble monomer C accounts for 10% -20%, the oil-soluble monomer A accounts for 60% -80%, and the oil-soluble polymer B accounts for 10% -30% based on 100% of the total amount of the oil-soluble monomer A, the oil-soluble polymer B and the water-soluble monomer C; based on the total mass of the oil-soluble monomer A, the oil-soluble polymer B and the water-soluble monomer C, the addition amount of the emulsifier A is 2% -3%, the addition amount of the emulsifier B is 2% -3%, the addition amount of the cross-linking agent is 0.1% -0.5%, and the addition amount of the initiator is 0.5% -2.0%.
  7. 7. The preparation method according to claim 1, wherein the temperature of thermal polymerization is 70-80 ℃; the pH value of the water phase is regulated to 7.5-8.5 by a 20% NaOH aqueous solution.
  8. 8. The preparation method of claim 1, wherein the semi-interpenetrating network polymer plugging agent has a particle size of 0.05-50 μm and D 50 -15 μm.
  9. 9. A semi-interpenetrating network polymer plugging agent for drilling fluid, which is prepared by the preparation method of any one of claims 1-8.
  10. 10. Use of a semi-interpenetrating network polymer plugging agent for drilling fluids prepared by the preparation method of any one of claims 1-8 in oil-based drilling fluids, water-based drilling fluids or high-temperature formations above 180 ℃.

Description

Semi-interpenetrating network polymer plugging agent for drilling fluid, and preparation method and application thereof Technical Field The invention belongs to the technical field of drilling fluid treatment agents in petroleum drilling engineering, and particularly relates to a semi-interpenetrating network polymer plugging agent for drilling fluid, and a preparation method and application thereof. Background In deep well ultra-deep well drilling, the problems of low pressure leakage, unstable stress, collapse and instability of the well wall and the like are frequent, the risks of lost circulation and blocking of the well are high, the treatment difficulty is high, and water-based and oil-based drilling fluids are generated. For example, the crack development of the red star block Wu Guping, the collapse and leakage coexist, the shale stratum of the Longmaxi group from tribute and Weiyuan blocks, the crushing stress release of the stratum of the industrial 7-well the Eastern Mountain temple is serious, and the geological crushing of the North Sang Damu group limestone, the southwest work area, the mouth group and the like is realized. When the drilling meets the micro-nano pore to develop the stratum, the phenomena of drilling fluid leakage and well wall instability collapse are easy to occur, the micro-nano plugging material is needed to be added to form a compact plugging layer, the invasion of the drilling fluid is reduced, the stratum bearing capacity is improved, the collapse caused by leakage is prevented, and meanwhile, the material is required to have a certain bonding effect to play a role in bonding and protecting the wall for further improving the collapse prevention effect. The elastic deformation, the bonding effect and the temperature resistance of the common polymer plugging material cannot be simultaneously considered, and the high-temperature plugging leakage-proof and collapse-proof effects cannot be simultaneously met. Therefore, a micro-nano plugging material with a special structure needs to be developed, and the micro-nano plugging material can be simultaneously deformed, bonded and resistant to high temperature, so that the compactness, the pressure bearing capacity and the bonding and wall protecting effect of a plugging layer are improved, and the purposes of effectively plugging micro-nano pores and improving the stability of a well wall are achieved. Disclosure of Invention In view of the above, the invention aims to provide a semi-interpenetrating network polymer plugging agent for drilling fluid, a preparation method and application thereof, wherein the temperature resistance of the plugging agent prepared by the method reaches 180 ℃, the plugging agent has good compatibility with oil-based drilling fluid and water-based drilling fluid, has obvious filtration reducing and plugging effects, can be used for plugging high-temperature stratum, and also has the function of bonding and protecting walls. The invention provides a preparation method of a semi-interpenetrating network polymer plugging agent for drilling fluid, which comprises the following steps: 1) Mixing an oil-soluble monomer A and an oil-soluble polymer B, wherein the oil-soluble polymer B is completely dissolved to obtain an oil phase; 2) Mixing an emulsifier A, an emulsifier B, a water-soluble organic monomer C and water to obtain a water phase; 3) Mixing 65% -70% of oil phase and water phase, and emulsifying to obtain an emulsion reaction mixed solution; 4) Carrying out heat preservation polymerization on the emulsion reaction mixed solution and a first-stage initiator to obtain emulsion after polymerization; 5) And continuing to perform heat preservation polymerization on the emulsion after polymerization, 30% -35% of residual oil phase, a cross-linking agent and a two-stage initiator to obtain the semi-interpenetrating network polymer plugging agent. According to the invention, the oil-soluble monomer A and the oil-soluble polymer B are mixed, and the oil-soluble polymer B is completely dissolved to obtain an oil phase. The oil-soluble monomer A is one or more selected from butyl methacrylate, methyl acrylate, vinyl acetate, butyl acrylate and isooctyl acrylate. The invention preferably uses the oil-soluble monomer A to clean three times with 20% NaOH aqueous solution for standby. The oil-soluble polymer B is one or more selected from polystyrene, styrene-acrylic ester copolymer, polymethyl methacrylate, acrylic ester homopolymer, acrylic ester copolymer and styrene-butadiene rubber. The method comprises the steps of adding the cleaned oil-soluble monomer A into a three-neck flask with a stirring rod, adding the oil-soluble polymer B, stirring, and fully dissolving to obtain an oil phase. The invention mixes the emulsifier A, the emulsifier B, the water-soluble organic monomer C and water to obtain the water phase. The invention preferably adds the emulsifier A and the emulsifier B into water in sequence, and