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CN-121991674-A - Composite oil displacement system and preparation method thereof

CN121991674ACN 121991674 ACN121991674 ACN 121991674ACN-121991674-A

Abstract

The application discloses a compound oil displacement system and a preparation method thereof, and belongs to the technical field of oilfield development. The composite oil displacement system mainly comprises polyacrylamide and a viscoelastic body, the viscosity of the system can be increased by 1-2 times on the basis of single polyacrylamide by utilizing the tackifying and suspending capabilities of the polyacrylamide to carry the viscoelastic body, the viscoelasticity of the system is greatly increased, and compared with a polymer oil displacement system, the system can be used for effectively improving the recovery ratio of an oil field. Compared with a polymer/surfactant oil displacement system, the system cost can be reduced by about 55 percent. Therefore, the compound oil displacement system provided by the application can not only improve the recovery ratio of an oil field, but also has lower cost.

Inventors

  • WANG WEI
  • WU XING
  • CUI DANDAN
  • WANG XIAOYAN
  • SUN CHEN
  • CAO XIAOMEI
  • YAN XI
  • ZHANG NAN
  • YE LONGYUN
  • ZHAO FENGXIANG

Assignees

  • 中国石油天然气股份有限公司

Dates

Publication Date
20260508
Application Date
20241104

Claims (10)

  1. 1. The compound oil displacement system is characterized by comprising the following components: Polyacrylamide, a viscoelastic body and water, Wherein the concentration of the polyacrylamide is 1500mg/L, and the concentration ratio of the viscoelastic body to the concentration of the polyacrylamide is 3:7-5:5; The viscoelastic body is obtained by polymerization reaction of acrylamide and N, N-methylene bisacrylamide.
  2. 2. The complex flooding system of claim 1, wherein the viscoelastic body is prepared from the raw materials comprising an initiator, anhydrous sodium carbonate and water.
  3. 3. The compound flooding system of claim 2, wherein the viscoelastic body comprises the following components in parts by mass in the preparation process: 15-20 parts of acrylamide, 1-5 parts of N, N-methylene bisacrylamide, 0.1-2 parts of initiator, 3-6 parts of anhydrous sodium carbonate and 45-60 parts of water.
  4. 4. The compound flooding system of claim 3, wherein said viscoelastic body is prepared according to the following preparation method: adding the water into a reaction container according to the mass parts of the components, adding the acrylamide monomer into the reaction container, and stirring until the solid is dissolved to obtain a first solution; adding the N, N-methylene bisacrylamide into the first solution, and stirring until the solid is dissolved to obtain a second solution; adding the initiator and the anhydrous sodium carbonate into the second solution, and stirring until the solid is dissolved to obtain a third solution; And reacting the third solution at a preset temperature for a preset period of time to obtain the viscoelastic body after the reaction.
  5. 5. The complex flooding system of claim 3 or 4, wherein said initiator is ammonium persulfate.
  6. 6. The compound flooding system of claim 4, wherein the preset temperature is 40 ℃ to 45 ℃ and the preset time period is 24 hours to 30 hours.
  7. 7. The compound flooding system of claim 2, wherein the viscoelastic body comprises the following components in parts by mass in the preparation process: 17 parts of acrylamide, 4 parts of N, N-methylene bisacrylamide, 0.5 part of initiator, 5 parts of anhydrous sodium carbonate and 59 parts of water.
  8. 8. The complex flooding system of claim 7, wherein said viscoelastic body is present at a concentration of 1000mg/L.
  9. 9. The complex flooding system of claim 7, wherein said viscoelastic body is present at a concentration of 1500mg/L.
  10. 10. A method for preparing the compound flooding system according to any one of claims 1 to 9, characterized in that the method comprises: Determining the volume of water and the concentration of the viscoelastic body; determining the mass of the viscoelastic body and the mass of the polyacrylamide based on the volume of the water and the concentration of the viscoelastic body; Weighing polyacrylamide and viscoelastic body with corresponding mass; adding water with corresponding volume into a reaction container, adding polyacrylamide with corresponding mass into the reaction container, and uniformly stirring; Adding viscoelastic bodies with corresponding mass into the reaction vessel, and uniformly stirring to obtain the compound oil displacement system.

Description

Composite oil displacement system and preparation method thereof Technical Field The application relates to the technical field of oilfield development, in particular to a compound oil displacement system and a preparation method thereof. Background At present, most oil fields enter a development stage with high water content and high extraction degree, invalid circulation of water injection is aggravated, and difficulties of stable production and improvement of recovery efficiency are increased year by year, so that the technology of improving recovery efficiency of tertiary oil recovery suitable for the high water content old oil fields is required to be continuously overcome, and the long-term stable production of the old oil fields can be effectively supported. In the related art, polymer flooding systems and polymer/surfactant flooding systems are used in many cases. The polymer oil displacement system has a smaller sweep range, and the effect of improving the recovery ratio is not obvious. While polymer/surfactant flooding systems can increase recovery, they are costly. Therefore, there is a need to provide an oil displacement system that can both enhance oil recovery and have lower costs. Disclosure of Invention The embodiment of the application provides a compound oil displacement system and a preparation method thereof, wherein the compound oil displacement system not only can improve the recovery ratio of an oil field, but also has lower cost. The technical scheme is as follows: In one aspect, a composite flooding system is provided, the composite flooding system comprising the following components: Polyacrylamide, a viscoelastic body and water, Wherein the concentration of the polyacrylamide is 1500mg/L, and the concentration ratio of the viscoelastic body to the concentration of the polyacrylamide is 3:7-5:5; The viscoelastic body is obtained by polymerization reaction of acrylamide and N, N-methylene bisacrylamide. In one possible implementation, the viscoelastic body is prepared from a raw material further comprising an initiator, anhydrous sodium carbonate and water. In another possible implementation, the viscoelastic body is prepared from the following components in parts by weight: 15-20 parts of acrylamide, 1-5 parts of N, N-methylene bisacrylamide, 0.1-2 parts of initiator, 3-6 parts of anhydrous sodium carbonate and 45-60 parts of water. In another possible implementation, the viscoelastic body is prepared according to the following preparation method: adding the water into a reaction container according to the mass parts of the components, adding the acrylamide monomer into the reaction container, and stirring until the solid is dissolved to obtain a first solution; adding the N, N-methylene bisacrylamide into the first solution, and stirring until the solid is dissolved to obtain a second solution; adding the initiator and the anhydrous sodium carbonate into the second solution, and stirring until the solid is dissolved to obtain a third solution; And reacting the third solution at a preset temperature for a preset period of time to obtain the viscoelastic body after the reaction. In another possible implementation, the initiator is ammonium persulfate. In another possible implementation manner, the preset temperature is 40 ℃ to 45 ℃, and the preset time period is 24 to 30 hours. In another possible implementation manner, the viscoelastic body comprises the following components in parts by weight in the preparation process: 17 parts of acrylamide, 4 parts of N, N-methylene bisacrylamide, 0.5 part of initiator, 5 parts of anhydrous sodium carbonate and 59 parts of water. In another possible implementation, the concentration of the viscoelastic body is 1000mg/L. In another possible implementation, the concentration of the viscoelastic body is 1500mg/L. In another aspect, a method for preparing a composite flooding system is provided, the method comprising: Determining the volume of water and the concentration of the viscoelastic body; determining the mass of the viscoelastic body and the mass of the polyacrylamide based on the volume of the water and the concentration of the viscoelastic body; Weighing polyacrylamide and viscoelastic body with corresponding mass; adding water with corresponding volume into a reaction container, adding polyacrylamide with corresponding mass into the reaction container, and uniformly stirring; Adding viscoelastic bodies with corresponding mass into the reaction vessel, and uniformly stirring to obtain the compound oil displacement system. The embodiment of the application provides a compound oil displacement system which comprises polyacrylamide and a viscoelastic body, wherein the viscosity increasing and suspending capacity of the polyacrylamide is utilized to carry the viscoelastic body, so that the viscosity of the system can be increased by 1-2 times on the basis of single polyacrylamide, the viscoelasticity of the system is greatly increased, and co