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CN-122012065-A - Resistance reducing agent for polyacrylamide fracturing and preparation method thereof

CN122012065ACN 122012065 ACN122012065 ACN 122012065ACN-122012065-A

Abstract

The invention belongs to the technical field of preparation of polyacrylamide resistance reducers, and particularly relates to a resistance reducer for polyacrylamide fracturing and a preparation method thereof. The preparation method comprises the steps of preparing polyacrylamide core microspheres by adopting raw materials of an acrylamide monomer, a temperature-resistant salt-resistant monomer and a contracture tail hydrophobic monomer through template polymerization, forming a crude product through aqueous-oil phase polymerization coating, and finally modifying by a cationic silane coupling agent to obtain the resistance reducing agent. Through the design of the porous inner core and the twin tail hydrophobic monomer, the resistance reducing agent has excellent thermal stability and salt resistance in a high-salt environment.

Inventors

  • JIANG ZHAOLIANG
  • WANG JILIN
  • ZHU BINFANG

Assignees

  • 东营科创生物化工有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (9)

  1. 1. The preparation method of the resistance reducing agent for the polyacrylamide fracturing is characterized by comprising the following steps of: s1, preparing polyacrylamide core microspheres by template polymerization by adopting raw materials of an acrylamide monomer, a temperature-resistant salt-resistant monomer, a twin-tail hydrophobic monomer, a cationic stabilizer, an initiator A and a cross-linking agent A, wherein the reaction temperature in the template polymerization stage is 40-50 ℃ and the reaction time is 6-8 hours, and the mass ratio of the acrylamide monomer to the temperature-resistant salt-resistant monomer to the twin-tail hydrophobic monomer to the cationic stabilizer to the initiator A to the cross-linking agent A is 10-18:3-8:2-5:0.3-0.8:0.1-0.5:0.05-0.15; s2, mixing raw materials of the polyacrylamide core microsphere, the emulsifier and the crosslinking accelerator with deionized water, and shearing and emulsifying at the rotating speed of 6000-8000r/min for 10-15min to obtain aqueous phase dispersion liquid, wherein the mass ratio of the polyacrylamide core microsphere to the emulsifier to the crosslinking accelerator is 8-15:0.8-1.2:0.2-0.5; S3, mixing raw materials of N, N-dimethylacrylamide, N-vinyl pyrrolidone, an initiator B and a cross-linking agent B with ethyl acetate to obtain an oil phase, and carrying out polymerization coating on the oil phase and the oil phase in an inert atmosphere to obtain a crude product of the friction reducer, wherein the polymerization reaction temperature is 60-65 ℃, the polymerization reaction time is 4-6h, and the mass ratio of the ethyl acetate, the N, N-dimethylacrylamide, the N-vinyl pyrrolidone, the initiator B and the cross-linking agent B is 55-70:6-12:4-8:0.1-0.4:0.03-0.06; s4, dispersing the crude resistance reducing agent in deionized water, adding a cationic silane coupling agent, and performing ultrasonic dispersion, filtration and drying to obtain the resistance reducing agent, wherein the mass ratio of the deionized water to the crude resistance reducing agent to the cationic silane coupling agent is 180-300:38-48:3-8.
  2. 2. The preparation method of the resistance reducing agent for polyacrylamide fracturing according to claim 1, wherein the preparation method of the twin-tail hydrophobic monomer is as follows: A1, adding bromolong-chain alkyl and long-chain alkylamine into acetonitrile, adding dichloromethane and sodium hydroxide solution after the rising reaction is finished, and obtaining white crystals through suction filtration, recrystallization and drying; And A2, adding white crystals into dichloromethane, dropwise adding methacryloyl chloride under the ice bath condition, reacting under the inert atmosphere, and separating, washing and rotary steaming after the reaction is finished to obtain the twin-tail hydrophobic monomer.
  3. 3. The method for producing a resistance-reducing agent for use in polyacrylamide-based fracturing according to claim 2, wherein in the step A1, the number of carbon atoms in the brominated long-chain alkyl group is 8 to 16, and the number of carbon atoms in the long-chain alkylamine is 8 to 16.
  4. 4. The preparation method of the resistance reducing agent for the polyacrylamide fracturing is characterized in that step S1 is characterized in that a template agent is added into deionized water, an acrylamide monomer, a temperature-resistant and salt-resistant monomer, a twin-tail hydrophobic monomer and a cationic stabilizer are added after stirring and dispersing, an initiator A and a cross-linking agent A are added under inert atmosphere after ultrasonic dispersing, the temperature is increased to 40-50 ℃, the constant temperature stirring reaction is carried out for 6-8 hours, the template agent is washed after the reaction is finished, and the polyacrylamide core microsphere is obtained after washing, filtering and drying.
  5. 5. The preparation method of the resistance reducing agent for polyacrylamide fracturing according to claim 4, wherein the initiator A is obtained by mixing ammonium persulfate and sodium bisulfate amine in a mass ratio of 1-2:1, and the cross-linking agent is N, N' -methylenebisacrylamide.
  6. 6. The preparation method of the resistance reducing agent for the polyacrylamide fracturing is characterized in that in the step S2, specifically, polyacrylamide core microspheres, an emulsifying agent and a crosslinking accelerator are added into deionized water, a pH buffering agent is added after uniform mixing, the pH of a system is regulated to 7.0, and aqueous phase dispersion liquid is obtained after high-speed shearing and emulsification.
  7. 7. The preparation method of the resistance reducing agent for the polyacrylamide fracturing is characterized in that in the step S3, N-dimethylacrylamide, N-vinyl pyrrolidone, an initiator B and a cross-linking agent B are added into ethyl acetate, an oil phase is obtained after uniform stirring, the temperature is increased to 50-60 ℃, the oil phase is dropwise added into an aqueous dispersion liquid under an inert atmosphere, the temperature is increased to 60-65 ℃ after the dropwise addition is completed, the temperature is kept for 4-6 hours, the reaction is naturally cooled to room temperature, a demulsifier is added into the reaction product, and a crude resistance reducing agent product is obtained after the uniform stirring, centrifugation, washing and drying.
  8. 8. The preparation method of the resistance reducing agent for the polyacrylamide fracturing is characterized in that in step S4, the crude resistance reducing agent is dispersed in deionized water, then cationic silane coupling agent is added, the temperature is increased to 40-50 ℃ after ultrasonic dispersion, the reaction is carried out for 2-4 hours, and the resistance reducing agent is obtained after filtration and drying.
  9. 9. The resistance reducing agent for polyacrylamide fracturing, which is characterized by being prepared by adopting the preparation method of the resistance reducing agent for polyacrylamide fracturing according to any one of claims 1-8.

Description

Resistance reducing agent for polyacrylamide fracturing and preparation method thereof Technical Field The invention belongs to the technical field of preparation of polyacrylamide resistance reducers, and particularly relates to a resistance reducer for polyacrylamide fracturing and a preparation method thereof. Background In the petroleum and natural gas exploitation process, hydraulic fracturing is a key technical means for improving low-permeability oil and gas reservoirs and improving oil and gas yield. In the fracturing construction, the fracturing fluid needs to be pumped into the stratum rapidly under high pressure, and the on-way resistance generated when the fluid flows in the pipeline consumes a large amount of energy to influence the fracturing effect. Therefore, adding a resistance reducing agent into the fracturing fluid to reduce the fluid flow resistance is one of the core requirements of hydraulic fracturing technology. The polyacrylamide polymer has good water solubility, thickening property and resistance reducing property, so that the polyacrylamide polymer is one of the resistance reducing agents for fracturing which are widely applied at present. However, the polymer is easy to hydrolyze at high temperature, so that the resistance-reducing efficiency is obviously reduced, and in a high-salt stratum environment, molecular chains are shrunk, and the thickening resistance-reducing performance is lost. The Chinese patent publication No. CN104559998B discloses a slick water for shale gas fracturing and a preparation method thereof, wherein the slick water consists of an emulsion resistance-reducing agent, a clay stabilizer, a cleanup additive, potassium chloride, a bactericide and water, wherein the emulsion resistance-reducing agent is an anionic polyacrylamide copolymer, the prepared slick water has small adsorption to a shale gas layer, and the damage to a reservoir caused by a high polymer additive during rock adsorption can be greatly reduced. The Chinese patent publication No. CN115947891B discloses a heat-resistant salt-tolerant instant polyacrylamide and a preparation method thereof, wherein a benzene ring-containing rigid heat-resistant salt-tolerant monomer and a fluorine-containing cationic hydrophobic monomer are introduced on the basis of an acrylamide monomer and a sodium acrylate monomer to carry out polyacrylamide modification, polymerization is initiated to obtain the heat-resistant salt-tolerant instant polyacrylamide, and the polymer meets the requirement of online instant dissolution of the polymer for fracturing fluid by means of medium-low molecular structure design, low hydrophobic monomer content, introduction of strong hydrophilic groups carboxyl groups and sulfonic groups and a synthetic instant technology. However, the existing resistance reducing agent has poor structural uniformity, is difficult to form a stable space network structure, and has insufficient adaptability in complex stratum environments, so that the resistance reducing agent for polyacrylamide fracturing, which has excellent temperature resistance, salt resistance, high resistance reduction and good stability, is developed and becomes a hot spot for research in the current petroleum exploitation field. Disclosure of Invention In order to solve at least one of the technical problems, the invention provides a preparation method of a resistance reducing agent for polyacrylamide fracturing, which comprises the following steps: s1, preparing polyacrylamide core microspheres by template polymerization by adopting raw materials of an acrylamide monomer, a temperature-resistant salt-resistant monomer, a twin-tail hydrophobic monomer, a cationic stabilizer, an initiator A and a cross-linking agent A, wherein the reaction temperature in the template polymerization stage is 40-50 ℃ and the reaction time is 6-8 hours, and the mass ratio of the acrylamide monomer to the temperature-resistant salt-resistant monomer to the twin-tail hydrophobic monomer to the cationic stabilizer to the initiator A to the cross-linking agent A is 10-18:3-8:2-5:0.3-0.8:0.1-0.5:0.05-0.15; s2, mixing raw materials of the polyacrylamide core microsphere, the emulsifier and the crosslinking accelerator with deionized water, and shearing and emulsifying at the rotating speed of 6000-8000r/min for 10-15min to obtain aqueous phase dispersion liquid, wherein the mass ratio of the polyacrylamide core microsphere to the emulsifier to the crosslinking accelerator is 8-15:0.8-1.2:0.2-0.5; S3, mixing raw materials of N, N-dimethylacrylamide, N-vinyl pyrrolidone, an initiator B and a cross-linking agent B with ethyl acetate to obtain an oil phase, and carrying out polymerization coating on the oil phase and the oil phase in an inert atmosphere to obtain a crude product of the friction reducer, wherein the polymerization reaction temperature is 60-65 ℃, the polymerization reaction time is 4-6h, and the mass ratio of the ethyl acetate, the N, N-d