EXPRESS METHOD FOR CHEMICAL REAGENTS SELECTION FOR INCREASING OIL RECOVERY OF LOW-PERMEABILITY RESERVOIRS

Abstract

The choice of hard-to-recover reservoir (HRR) engineering technologies is one of the actual problems facing oil companies in the Russian Federation and the World. In order to increase the efficiency of the development of such fields various methods for production intensification are used to obtain an economically profitable industrial oil inflow. It is possible to use surfactant flooding to solve this problem. The surfactant efficacy results from the fact that aqueous surfactants solutions even at low concentrations dramatically decrease the oil/water/rock interfacial tension that results to changing wettability, allowing to increase the oil inflow.The purpose of this work is to study an alternative method of testing the effect of surfactant solutions on oil recovery. The method consists in mass testing using a laboratory petrophysical centrifuge to identify the most promising solutions, followed by the classical filtration method. The method of centrifugation is based on the substitution of one fluid in the pores of the core sample by another, occurring at a pressure difference at the boundary of the two phases under the action of centrifugal force. The suggested method will allow massively and in a short time to identify the most effective solutions for specific geological conditions.To carry out this work, three surfactant solutions were selected that were tested for resistance to mineral aggression and temperature, surface tensions and phase behaviors were determined. The object of the study was the core material of the formations of the AS, BS and YuS groups of one of the deposits of Western Siberia. Two series of experiments were carried out: classical filtration tests and centrifugation of core samples under conditions of initial and residual oil saturation.The results of the experiments have shown the effectiveness and prospects of using the centrifugation method for mass testing of surfactant solutions as displacing agents. The described method is express and cannot completely replace the classical filtration experiment due to non-compliance with an important criterion – the thermobaric conditions of the reservoir.