Author(s)

Xiansong Zhang, Hao Chen, Bowen Li, Bao Zhen Li, He Tang

Corresponding Author

Xiansong Zhang

Abstract

The discovery of the natural gases with varying CO2 content (24-90%) on top of the oil reservoir provides big potential for gas flooding in Qinhuangdao oilfield. However, the contamination of the gases, which is mainly methane, greatly limits the promotion of miscible flooding. In this paper, near-miscible flooding was proposed considering the comparative recovery effect as increasingly lab tests and field tests indicated. In this paper, the effect of impurity content in the production gas on the near-miscible interval are studied. The lower limit of CO2 content for production gas re-injection in the targeted well are determined. It is concluded that CO2 content higher than 50% can achieve near-miscible flooding.

Keywords

offshore oilfield, production gas re-injection, lower limit of CO2 content.