Hydrophobically associating polymer and mixed surfactant binary compound oil displacement system

Abstract

The invention relates to a hydrophobically associating polymer and mixed surfactant binary compound oil displacement system for use in tertiary oil extraction. The system mainly comprises the following components in percentage by weight: 0.1 to 0.3 percent of hydrophobically associating polymer, 0.1 to 0.6 percent of surfactant and 99.2 to 99.8 percent of water. The hydrophobically associating polymer in the system has high temperature resistance, high salt resistance and viscosity increasing capacity and can largely reduce dosage of polymer; and with high solubilizing capacity, the polymer can increase the dissolution of the surfactant in sewage, thereby increasing the use concentration of the surfactant. The oil displacement system which is dissolved by sewage from extraction can save lots of fresh water; with high viscosity increasing capacity, the system can effectively control flow rate, increase swept volume, increase oil water interface tension to 10<-3>mN / m and increase the oil extraction rate; and because of high stability and injection property, the system can be injected in large dose. According to an indoor oil displacement experiment, the binary compound oil displacement system can improve the extraction rate by over 20 percent compared with that of water displacement. The system without alkali avoids serious damage to the oil layer and corrosion and damage to oilpipes and has a great application prospect.

Description

technical field [0001] The present invention relates to a binary compound flooding system used in enhanced oil recovery in tertiary oil recovery, specifically, a hydrophobic association polymer-mixed surfactant binary compound flooding used in tertiary oil recovery system. Background technique [0002] my country's main mature oilfields are gradually entering a period of high water cut and extremely high water cut. It is difficult to stabilize production and the contradictions in development are becoming increasingly prominent. The chemical composite flooding technology, which appeared in the 1970s and 1980s, has been widely valued by research fields at home and abroad, and is considered to be a more potential tertiary oil recovery technology after polymer flooding. At home and abroad, a large number of indoor test researches began in the mid-1980s, and more than a dozen mine tests were carried out, all of which were technically successful. However, some problems have been...

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Problems solved by technology

However, at present, binary compound flooding systems generally use partially hydrolyzed polyacrylamide as a thickener. Conventional partially hydrolyzed polyacrylamide has a large viscosity loss in brine, so fresh water is often used to dissolve it, which wastes fresh water resources and cannot make the produced sewage get better. Utilization, no place to discharge; polyacrylamide solution is easy to degrade when placed for a long time or placed at a higher temperature, so the polymer concentration must be increased to control the mobility ratio, which increases the investment cost

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