Abstract
In order to enhance oil recovery of a conventional oil reservoir by CO2 flooding, the changes in the properties of the crude oil before and after CO2 flooding are systematically investigated by on-site sampling and experimental testing. The results show that, after CO2 flooding, the light hydrocarbons of the produced crude oil is increased and the heavy hydrocarbons of the produced crude oil is decreased due to the deposition of resins and asphaltenes in the pores of the formation. In addition, the produced fluid (a mixture of oil and water) has a high water separation rate, the oil- water interface has a high tension value, and the crude oil has a high acid value and a low viscosity. The conclusions can provide a certain guidance for high-efficiency development of a conventional oil reservoir by CO2 flooding.
Acknowledgments
The authors gratefully acknowledge the financial supports by the National Science Foundation of China under Grant numbers 51774236.