The Preparation And Performance Of Microemulsion For Oil-Gas Resources

The reservoir wettability is important to flood development which received general concern. Influx water flowback and oil and gas recovery both improved when the rock in the intermediate or weak water wet. Study on the law of cationic surfactants and non-ionic surfactants adsorption on the core by ultraviolet-visible spectrophotometers, a microemulsion was developed and used to alter the wettability of the rock.The experimental results show that Geminil231adsorbed on the core surface will alter the water-wet rock into oil-wet, and the saturated adsorption was143.3mg/g. The saturated adsorption of OP-10was14.6mg/g, the core keeping water-wet. Gemini1231and OP mixed in different proportions adsorbed on the core surface alter the water-wet rock into different wettability. The surfactant adsorption the cores will not affected by inorganic salts, and the adsorption is permanent.A series of microemulsions have been prepared in the lab which composed of cationic surfactant Gemini1231, non-ionic surfactants and additives. The main properties of the microemulsions have been studied. The experimental results show that water and oil can both dissolve in the microemulsion, transparant up to104℃Moreover, The potential of core surface can be reduced by the way of adsorption. The microemulsion can reduce the surface tension of the working fluid significantly, and transform the wettability of the hydrophilic and hydrophobic core to intermediate or weak water wet, which is an effective methods to improve influx water flowback in reservoir stimulation, decrease formation damage,and enhance water injectivity. The microemulsion have good compatibility with fracturing fluid, and can be used as clean up additive.The microemulsion can be effective to reduce the damage of encroaching water, enhance the injection capability during oil-gas reservoir exploitation, and improve the flowback during facture stimulation process. The microemulsion is simple to preparated, which water and oil can both dissolve in, with low interfacial tension, very promising.