Hydrophobically associated polymer-composite surfactant binary combination flooding system and method

Abstract

The invention discloses a hydrophobically associated polymer-composite surfactant binary combination flooding system and method. The hydrophobically associated polymer-composite surfactant binary combination flooding system mainly comprises the following components in percentage by weight: 0.08-0.3 wt% of hydrophobically associated polymer, 0.05-0.5 wt% of composite surfactant and 99.2-99.87 wt% of water. The composite surfactant is composed of the following components in percentage by weight: 50-70 wt% of fatty acid diester disulfonate and 30-50 wt% of oleic acid diglycollic amide. The hydrophobically associated polymer-composite surfactant binary combination flooding system has favorable tackifying property, and enables the oil-water interfacial tension to reach 10<-3>nM / m under low surfactant concentration (0.05%), thereby enhancing the displacement efficiency; and the hydrophobically associated polymer-composite surfactant binary combination flooding system can enhance the recovery rate by more than 30% on the basis of water flooding, lowers the polymer consumption by more than 50% as compared with the 250-million ultrahigh-molecular-weight polyacrylamide binary combination flooding system with close properties, and enhances the recovery rate by 6%, thereby greatly lowering the oil displacement cost on the premise of increasing the yield.

Description

technical field [0001] The invention relates to a binary compound flooding system used in tertiary oil recovery to enhance oil recovery, in particular to a hydrophobic association polymer-composite surfactant binary compound flooding system and method used in tertiary oil recovery. Background technique [0002] After primary and secondary oil recovery in most oilfields in my country, the recovery rate only reaches 30%~50%, and there is still a large amount of crude oil stored in the ground in the form of residual oil. During the high water cut period, it is difficult to stabilize production, and the development contradiction becomes increasingly prominent. It has become a very urgent task to further increase the recovery rate of proven reserves. Chemical composite flooding technology is considered to be a more potential tertiary oil recovery technology after polymer flooding. The geological reserves of chemical flooding are more than 6 billion tons, and the recoverable reser...

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Problems solved by technology

However, some negative problems were also exposed during the implementation of the field test: the addition of strong alkali will cause scaling and clay migration problems, damage the formation and affect the normal production of oil wells; the addition of alkali will also greatly reduce the viscosity of the polymer, increase the The amount of polymer used increases the cost of oil displacement; the serious emulsification with crude oil brings difficulties to the subsequent treatment process of produced fluid

[0006] In summary, how to overcome the high cost of using partially hydrolyzed polyacrylamide as a thickener and oil sulfonate or carboxylate as a surfactant in the existing binary compound flooding system, and the oil-water interfacial tension that must be used in conjunction with alkali to reach 10 ～3 Problems such as mN / m are technical problems to be solved in this industry

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