A kind of vesicle oil displacement agent formed by anionic surfactant complex system and its application

Abstract

The invention relates to a vesicle oil-displacing agent formed by an anionic surfactant compounded system. The vesicle oil-displacing agent is prepared by mixing a surfactant B, a surfactant C and mineralized water and stirring a mixture under the trigger of an auxiliary agent. Mass concentration of the surfactant B and the surfactant C is 0.3-0.8 wt%. The ratio of the addition amount of the auxiliary agent to the total mass of the surfactants B and C is 1:3-5. Total salinity of the mineralized water is 500-5000 ppm. The vesicle oil-displacing agent of the anionic surfactant compounded system has strong oil-water interface adsorption tendency. By in-situ assembling, a predetermined interface layer is formed. Thus, interfacial tension can be rapidly reduced to an ultralow level by oil-water. Without any alkali, 10<-3>mN.m<-1> of ultralow interfacial tension can be formed with crude oil. The effect of reducing the oil-water interfacial tension is prominent, and the action time is short. The interfacial tension can be reduced to 10<-3>mN.m<-1> within 10-15 min. The vesicle oil-displacing agent is suitable for tertiary oil recovery for enhancing crude oil recovery.

Description

technical field [0001] The invention relates to a vesicle oil displacement agent formed by an anionic surfactant compound system, which can quickly reduce the oil-water interfacial tension to an ultra-low (10 -3 mN·m -1 ), which is applied to enhance oil recovery in tertiary oil recovery, and belongs to the field of oilfield chemistry technology. Background technique [0002] Petroleum is a very important non-renewable resource. With the rapid economic growth, the society's demand for oil has risen sharply, and the possibility of rediscovering large reserves of oil reservoirs has decreased, making the improvement of the recovery rate of developed oil fields attract much attention. It is imminent to adopt technical means to enhance the recovery factor of developed oilfields. [0003] During oil production, the fluid flow in the reservoir is affected by geological factors such as reservoir sandstone pore structure and system wettability, as well as factors such as crude oil / ...

AI Technical Summary

Problems solved by technology

[0005] At present, the development potential of high-salt oil reservoirs is great, but due to the challenge brought by high salinity to the salt resistance of surfactants, most surfactant systems cannot be formed under high-salt conditions, which can reduce the interfacial tension of oil and water. Ultra-low micelles or microemulsions, which can be applied to high-salt reservoirs to enhance oil recovery systems and related technologies are seriously lacking

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