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CN-121991673-A - Binary composite system oil displacement agent, preparation method and application

CN121991673ACN 121991673 ACN121991673 ACN 121991673ACN-121991673-A

Abstract

The invention belongs to the technical field of oil displacement agents, and particularly relates to a binary composite system oil displacement agent, a preparation method and application thereof. The binary composite system oil displacement agent comprises the following raw materials, by weight, 0.05-0.15% of sodium laureth sulfate, 0.3-0.5% of double-tailed hydrophobic association polymer and saline, wherein the double-tailed hydrophobic association polymer is prepared by reacting diisocyanato alkyl acid with organic amine to prepare a double-tailed hydrophobic compound, the double-tailed hydrophobic compound is grafted onto a copolymer through transesterification, and the copolymer polymerization monomer comprises acrylamide, unsaturated sulfonic acid and hydroxyacrylate in a molar ratio of 80-90:10-20:0.5-3, and the mass ratio of the double-tailed hydrophobic compound to the copolymer is 5-15:100. The double-tail hydrophobic groups form an association network, so that the emulsifying oil carrying capacity and viscosity are improved, the hydrophilic property, calcium and magnesium tolerance and the viscosity loss under high salt are enhanced by sulfonic acid groups and amide groups, the polyoxyethylene chain segment is formed into a hydration protective layer in the association micro-area, and the low interfacial tension, the strong emulsifying oil carrying capacity and the excellent salt tolerance are realized.

Inventors

  • ZHANG CHUNLONG
  • LI YOULIANG
  • MA SHUO
  • HOU DAWEI
  • MAO LIFENG

Assignees

  • 大庆永铸石油技术开发有限公司

Dates

Publication Date
20260508
Application Date
20260410

Claims (10)

  1. 1. A binary composite system oil displacement agent is characterized by comprising the following raw materials, by weight, 0.05-0.15% of sodium laureth sulfate, 0.3-0.5% of a double-tail type hydrophobic association polymer and the balance of saline water, wherein the double-tail type hydrophobic association polymer is prepared by a preparation method comprising the steps of reacting alkyl diisocyanato with organic amine to prepare a double-tail type hydrophobic compound, grafting the double-tail type hydrophobic compound onto a copolymer through transesterification, and polymerizing monomers of the copolymer comprise acrylamide, unsaturated sulfonic acid and hydroxyacrylate, wherein the molar ratio of the acrylamide to the unsaturated sulfonic acid to the hydroxyacrylate is 80-90:10-20:0.5-3, and the mass ratio of the double-tail type hydrophobic compound to the copolymer is 5-15:100.
  2. 2. The binary composite system oil displacement agent according to claim 1, wherein the molar ratio of the alkyl diisocyanate to the organic amine is 1:2.04-2.08.
  3. 3. The binary composite system oil displacement agent according to claim 1, wherein the alkyl diisocyanate is one or a combination of two of L-lysine diisocyanate and methyl 2, 6-diisocyanato, and the organic amine is at least one of C4-C10 aliphatic amine and C4-C10 alkylaniline.
  4. 4. The binary composite system oil displacement agent according to claim 1, wherein the molar ratio of the acrylamide to the unsaturated sulfonic acid to the hydroxy acrylic acid ester is 80-90:10-20:1.5-3, and the viscosity average molecular weight of the copolymer is 1800-2200 ten thousand.
  5. 5. The binary composite system oil displacement agent according to claim 1, wherein the hydroxy acrylic ester is at least one selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate, and the unsaturated sulfonic acid is at least one selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfonic acid and methacrylic sulfonic acid.
  6. 6. The binary composite system oil displacement agent according to claim 1, wherein the mass ratio of the double-tailed hydrophobic compound to the copolymer is 10-15:100.
  7. 7. The binary composite system oil displacement agent according to claim 1, wherein the two-tailed hydrophobically associating polymer is prepared by a method comprising the steps of: 1) Dissolving alkyl diisocyanate in an anhydrous organic solvent, dropwise adding an organic amine solution under the condition of temperature control and stirring, and carrying out heat preservation reaction to obtain a double-tail hydrophobic compound; 2) Adding acrylamide, unsaturated sulfonic acid and hydroxy acrylic ester into water under an inert atmosphere, uniformly mixing to obtain a polymerized monomer solution, regulating the pH of the polymerized monomer solution to 6.5-7.5, heating, adding an initiator, and controlling the temperature to react to obtain a copolymer; 3) And (3) dissolving the copolymer, the double-tailed hydrophobic compound and the catalyst in an organic solvent, and heating to a reflux state for reaction to obtain the double-tailed hydrophobic association polymer.
  8. 8. The binary composite system oil displacement agent according to claim 7, wherein in the step 3), the organic solvent is at least one selected from DMF, DMSO, NMP, the catalyst is at least one selected from p-toluenesulfonic acid and sodium formate, the catalyst is 0.1-0.3wt% of the copolymer, and the reflux state reaction time is 5-8h.
  9. 9. The binary composite system oil displacement agent according to claim 1, wherein the sodium laureth sulfate is at least one selected from the group consisting of sodium laureth-8 sulfate, sodium laureth-7 sulfate and sodium laureth-5 sulfate, the total mineralization degree of the brine is 5000-30000mg/L, and the total content of calcium ions and magnesium ions is 0-3000mg/L.
  10. 10. The preparation method of the binary composite system oil displacement agent according to any one of claims 1 to 9 is characterized by comprising the following steps of adding hydrophobic association polymer into saline water for dissolution, and adding sodium laureth sulfate for dissolution to obtain the binary composite system oil displacement agent.

Description

Binary composite system oil displacement agent, preparation method and application Technical Field The invention belongs to the technical field of oil displacement agents, and particularly relates to a binary composite system oil displacement agent, a preparation method and application thereof. Background Along with the rapid development of the economy in China, the energy demand of various industries in society is increasing. Although the country has increased the investment of new energy sources such as nuclear energy and solar energy, petroleum, which is a conventional energy source, still occupies an extremely important position. At present, major large and medium-sized oil fields in China are in the middle and later stages of exploitation, part of oil fields are serious in ageing degree, comprehensive water content is over 85%, recovery ratio is reduced, and oil field productivity is in a generally decreasing situation. Chemical flooding is a method of oil recovery where chemical agents are added to the injected water to enhance recovery, these added chemical agents are often referred to as oil displacement agents. The oil displacement agent can improve the sweep efficiency or the oil washing efficiency by improving the viscosity of injected water, reducing the oil-water interfacial tension, changing the permeability of partial oil layer, and the like, and finally achieves the aim of improving the recovery ratio. According to different types of chemical agents of an oil displacement main body, chemical agents are divided into alkali agents, surfactant agents and polymer agents, and polymer/surfactant/alkali ternary composite agents and alkali-free polymer/surfactant binary composite agents which are developed for improving the defects and shortcomings of low oil displacement efficiency, high economic cost and the like of a single chemical agent later, wherein the alkali-free polymer/surfactant binary composite agents not only avoid the problem of low oil displacement efficiency of a single chemical agent, but also avoid the problems of oil layer scaling, polymer viscosity reduction and the like caused by adding alkali, and the application is wider, and the hydrophobic association polymer-surfactant binary composition and a composite precursor system thereof are disclosed as patent CN108314998B, and comprise the following components: 2) the binary compound flooding composition comprises fatty acid amide betaine, alkyl betaine, aromatic acid salt= (1-60): (20-60) compound surfactant, wherein the mass ratio of the hydrophobic association polymer to the compound surfactant is (0.5-3): (0.1-5), and the binary compound flooding composition can obtain lower interfacial tension, but has low emulsifying capacity of the oil-displacing agent, poor oil carrying capacity and limited recovery ratio improvement. The binary composite driving system and method for hydrophobic association polymer-composite surfactant disclosed by CN102876313B comprises the main components of (wt%) 0.08-0.3% of hydrophobic association polymer, 0.05-0.5% of composite surfactant and 99.2-99.87% of water. The composite surfactant comprises (by weight) 50-70% of fatty acid diester disulfonate and 30-50% of oleic acid diethanolamide, and the binary composite flooding system has the advantages of no alkali, environmental protection, high interfacial activity and remarkable synergistic effect, but Ca 2+、Mg2+ carries two positive charges, and can form ionic bond bridging with two sulfonate groups in the molecular structure of the fatty acid diester disulfonate at the same time to generate calcium/magnesium fatty acid diester disulfonate precipitate which is difficult to dissolve in water, and the molecular structure and micelle state of the surfactant are damaged, so that the interfacial activity is lost, the interfacial tension of oil-water is remarkably increased, and the application of the binary composite flooding system in a high-calcium magnesium oil reservoir is limited. Therefore, it is necessary to develop an alkali-free binary compound system oil displacement agent with excellent interfacial activity and strong emulsifying capacity and good tolerance to calcium and magnesium ions. Disclosure of Invention The binary composite system oil displacement agent comprises a double-tailed hydrophobic association polymer and sodium laureth sulfate, wherein the double-tailed hydrophobic association polymer is prepared by reacting diisocyanato alkyl acid alkyl ester with organic amine to prepare a double-tailed hydrophobic compound, and then the double-tailed hydrophobic compound is grafted onto a copolymer prepared by copolymerizing acrylamide, unsaturated sulfonic acid and hydroxy acrylic ester, wherein the double-tailed hydrophobic group can form a strong association network, the emulsifying oil carrying capacity and solution viscosity of the system are improved, the hydrophilicity of molecules and the tolerance of calcium and magnesium ions ca