Formation Volume Factor Measurement and Prediction Model of CO2-Crude Oil System

• 1、Jilin Oilfield CO2 Development Company, Songyuan，Jilin 138000, China
• 2、Research Institute of Oil Production Technology, CNPC Jilin Oilfield Company, Songyuan，Jilin 138000, China
• 3、College of Petroleum Engineering, Yangtze University, Wuhan, Hubei 430100, China
• 4、 Key Laboratory of Drilling and Production Engineering for Oil and Gas, Hubei Province, Wuhan, Hubei 430100, China

Abstract：The accurate measurement and prediction of formation volume factor of CO2-crude oil mixed system are of great significance for the efficient development of CO2-EOR, CO2-CCS and volume method to calculate crude oil reserves. In order to determine the changing rule of crude oil formation volume factor by injecting CO2 into formation, the crude oil formation volume factor measurements under different temperature, pressure, CO2 content and water content were carried out, and the existing formation volume factor prediction model was compared and modified taking well 57025 in XJ oilfield as an example. The results show that under the same injection CO2 mole content, the formation volume factor of the mixed fluid decreases with the increase of pressure and increases with the elevation of temperature. Under the same temperature and pressure, the formation volume factor of the mixed fluid increases with the increase of CO2 mole fraction. Moreover, under the same conditions of temperature, pressure and CO2 mole content, the formation volume factor of mixed fluid decreases with the increase of water content. The revised formation volume factor prediction model takes into consideration of more comprehensive factors, leading to a low average relative error of only 1.98 %, which can meet the requirements of engineering calculation accuracy.

Keywords： CO2 flooding CO2-crude oil mixed system High-pressure physical property Formation volume factor model modification