Synthesis And Performance Of The Surfactant For Oil And Gas Exploration

The tertiary oil recovery research had become important issues, which aimed at improving oil recovery of remainder oil after water flooding or gas injection. Chemical flooding belongs to tertiary oil recovery, which includes alkali flooding, polymer flooding, surfactants flooding and compounds flooding. Compounds flooding were derived from the related chemical flooding and also had innovation. Although compound flooding was regarded as a new potential tertiary oil recovery technique, surfactants systems which can reduce oil-water interfacial tension to ultralow values are not developed in our country. Oversea corporations have developed a few surfactants system, but the prices are very expensive and these surfactants system cannot fit to various crude oil and need the help of alkali. As the influence of alkali, the use of polymers in the compounds flooding could increase, which could increase the costs of oil recovery and to a large extent confine the application of compounds flooding. So the exploration of surfactants system with high effectiveness and practicability has a great significant.This paper focused on the research of surface (interface) activity and solution viscosities of a new class of surfactants, gemini surfactants, and wished them overcoming the defects of common surfactants.Gemini surfactants have much higher surface activity and lower critical micelle concentration than corresponding conventional surfactants. The cmc decreases with the increase of alkyl carbon number, and increased with the increasing of temperature. But if the alkyl carbon number was above 16, the experimental cmc was higher than the expected value. Spacer had a complex influence on the cmc. The Krafft temperature of gemini surfactants is closed related to the alkyl carbon number and the spacer. The micelle thermodynamics studies show that the micellization is an entropy-driven process.The interfacial tension between oil (kerosene or oil) and gemini surfactants solution had been studied. Gemini surfactants solution can reduce the interfacial tension to ultralow values without additives, and Gemini surfactants had good synergistic effect with salts, which could acquire ultralow interfacial tension at a wide range of salt or surfactants concentration.The viscosity of gemini surfactants solution is also related to the alkyl carbon number and the spacer. Viscosities of gemini surfactants solution increase with the increase of alkyl carbon number and decrease with the increase the spacer. Viscosities of some gemini surfactants solution are dependent on time and temperature, which viscosities undergo a maximum with the increase of temperature or decrease with the time going. The mixtures of gemini surfactants and organic acid salts have better viscosification and maintain high viscosities even at high temperature.The interfacial viscosities of oil and gemini surfactants or conventional surfactant had been investigated using deep channel viscous interfacial viscometer. The interfacial viscosities are closely related to the nature of both surfactants and oil.From the research of gemini surfactants solution properties, it can be found that gemini surfactants can reduce the interfacial tension between oil and solution to ultralow. at a wide range without additives, and also appear remarkable viscosities in dilute solution. It is very hopeful to be used as a new series of oil displacement agents, which have both the abilities to reduce interfacial tension between oil and water to ultralow values, and the abilities to modify water phase viscosities. At the nonuse of alkali and polymer, these new oil displacement agents can have an effective oil displacement no less than that of ternary compound flooding. As the singleness of gemini surfactants flooding system component, the oil displacement effectiveness will not be influenced by chromatographic fractionation, and the oil formation harmed by use of alkali will be avoided.