Reservoir simulation of air injection assisted in situ upgrading process via subsurface electrical heating based on the horizontal well

Abstract

Heat transfer rate is slow during the in-situ upgrading process (ISU) via underground electrical heating, which is suitable for developing super heavy oil and oil shale reservoir. Considering the advantages of air injection process and horizontal well technology, an air injection assisted in situ upgrading process (AAISU) based on the horizontal well have been proposed and simulated. Reservoir simulation results show that air injection can improve heat transfer rate, enhance oil recovery by 11.4% and improve the energy efficiency from 4.54 GJ/GJ to 8.15 GJ/GJ comparing to the ISU process without air injection. Heating temperature and air injection rate are important for the AAISU process. When the heating temperature increase, the heat transfer rate and oil recovery increase, however, the energy efficiency are reduced stead. As for the effect of air injection rate, when the air injection rate increase from 500-4000 m3/day, the oil recovery and energy efficiency are rise first and then dropped, and the oil recovery and energy efficiency are the greatest when the air injection rate is 1000 m3/day.