Water-soluble micro-crosslinked copolymer, preparation and use thereof

Abstract

The invention discloses water-solubility micro-crosslinking copolymer, a method for making the same and an application of the same. The method is characterized in that: 20 portions of acrylamide, 0.5 to 15 portions of anion monomer, 0.1 to 6 portions of divinyl benzene, 0.5 to 50 portions of sodium laurylsulfate and 50 to 800 portions of deionized water are added in a three-necked reaction bottle, and the pH value of the solution is adjusted to between 4 and 9; after N2 is injected for 30 minutes, 0.001 to 0.2 portions of initiator persulphate is added in at a temperature of between 30 and 70 DEG C so as to carry out reaction for 6 to 36 hours, thereby obtaining PADM; then, the PADM is diluted by water to obtain a PADM solution, thereby obtaining the water-solubility micro-crosslinking copolymer which has ideal water solubility, copolymerization micro-crosslinking structure, difficult intramolecular crimp and molecular association capacity and can be used in oil expulsion. The copolymer is made into an aqueous solution with the mass concentration of between 0.3 and 3 g / L and the surfactant concentration of between 0.01 and 4 mmol / L, and then is added in a mixing vessel provided with a stirring device so as to be stirred evenly at room temperature, thereby obtaining a polymer oil displacement agent which is tackifying, salt resistant, thermotolerant and shear resistant and has excellent age resistance under the conditions of high salt and 110 DEG C. Moreover, the raw materials of PADM are easy to obtain; therefore, the water-solubility micro-crosslinking copolymer and the method have enormous application prospect in increasing crude oil recovery ratio.

Description

1. Technical field [0001] The invention relates to a water-soluble slightly cross-linked copolymer and its preparation method and application, belonging to the fields of polymer materials and enhanced oil recovery. 2. Technical background [0002] At present, many large oil fields in my country have entered the middle and late stages of exploitation, and the water content of the produced fluid is increasing day by day, and the water content of the produced fluid of many oil wells is as high as 90%. Therefore, chemical flooding by adding chemical agents to water injection has become an important technical measure in my country's petroleum industry, and polymer flooding is an effective technology in chemical flooding. The primary goal of polymer flooding is to develop cost-effective oil displacement polymers. The polymer used for oil displacement should have excellent water solubility, and the polymer can still maintain a strong viscosity increase under the environmental condi...

AI Technical Summary

Problems solved by technology

Due to the existence of the cross-linked structure, the rigidity of the polymer is enhanced, and the difficulty of conformational transformation is increased. It can show excellent temperature and salt resistance at high temperature (75-90°C) and high salinity, and maintain good thermal stability, but It is difficult to control the crosslinking degree and crosslinking distribution of the system, which makes its hydrodynamic radius large and easy to block the small pores of oil reservoirs, especially the pore throats of medium and low permeability reservoirs, which are only suitable for high permeability reservoirs

The other above-mentioned types of acrylamide-modified polymers have their own outstanding characteristics, but in order to make these polymers have good solubility, ionic groups are introduced into the molecular chains, and they all have a linear molecular structure. Therefore, There are also obvious defects. Due to the electrostatic shielding effect of salt on ions, the addition of salt will inevitably curl the linear macromolecular chain, and the viscosity of the solution will drop significantly, resulting in a large consumption of polymers for oil recovery. Requirements for Tertiary Oil Recovery of Reservoirs

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