Abstract:
Objective In order to improve the water flooding efficiency, a study on ultra-low interfacial tension surfactant for oil displacement in Bohai X Oilfield was carried out.
Methods According to the carbon atom number distribution analysis results of the saturated fraction and aromatic fraction of the crude oil, combining the principle of "similar phase dissolution" and the spatial complementary effect of hydrophobic end, the selection and mixing experiments of surfactants were carried out.
Results Hexadecyl dimethyl betaine and alkyl polyglycoside APG1214 were selected out from 5 surfactants. The ultra-low interfacial tension surfactant can be obtained by mixing the two surfactants at the mass ratio of 1∶2. The retention loss rate of obtained composite surfactant in core was small, which was only 11.2%. The emulsification and demulsification rates of crude oil were higher than 90% when the concentration of the composite surfactant was 0.1%-0.3%. The oil recovery can be increased by 9.4% over water flooding at the concentration of 0.2%.
Conclusions The field test results showed that the composite surfactant can obviously decrease water cut and increase oil production, it can be used to realize the purpose of "tapping the potential and increasing production" after water flooding in the oilfield.
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