Laboratory Experiments of Hydrocarbon Gas Flooding and Its Influencing Factors on Oil Recovery in a Low Permeability Reservoir with Medium Viscous Oil

Bihua Xian; Hongda Hao; Song Deng; Tiantian Sun; Hongze Wu; Lizhi Cheng; Zheng Tang; Xiaolong Gao; Yuting Wang; Songyan Cai; Erlong Yang

doi:10.1021/acsomega.3c09482

Laboratory Experiments of Hydrocarbon Gas Flooding and Its Influencing Factors on Oil Recovery in a Low Permeability Reservoir with Medium Viscous Oil

ACS Omega. 2024 Feb 8;9(7):8381-8396. doi: 10.1021/acsomega.3c09482. eCollection 2024 Feb 20.

Authors

Bihua Xian¹, Hongda Hao¹, Song Deng¹, Tiantian Sun¹, Hongze Wu¹, Lizhi Cheng¹, Zheng Tang¹, Xiaolong Gao², Yuting Wang^{3

4}, Songyan Cai⁵, Erlong Yang⁶

Affiliations

¹ School of Petroleum and Natural Gas Engineering, School of Energy, Changzhou University, Changzhou, Jiangsu 213164, China.
² Huabei Petroleum Tiancheng Industrial Group Co. Ltd., Renqiu, Hebei 062552,China.
³ Exploration and Development Research Institute of PetroChina Hubei Oilfield Company, Renqiu 062552, China.
⁴ China University of Geosciences, Wuhan 430074, China.
⁵ The Hong Kong Polytechnic University, Jiulongqu, Hong Kong 100872,China.
⁶ The Northeast Petroleum University, Heilongjiang, Daqing 163319, China.

Abstract

In view of the problems of low liquid production, a high proportion of high water cut wells, and poor development effect in the late stage of water flooding in the special sandstone reservoir of Niuquanhu "low permeability and medium viscosity crude oil", we carried out the research on hydrocarbon gas oil recovery and its influencing factors. First, the influence of different injected gas media on the physical properties of crude oil was analyzed. Second, the core displacement experiments of different gas injection media including CO₂, CH₄, and hydrocarbon gas were carried out by using the method of oil recovery comparison and optimization. Third, the indoor experimental study on the oil recovery of different influencing factors was carried out by using the method of controlling variables of influencing factors. Finally, the influence degree of different influencing factors on oil recovery was analyzed by a Spearman rank correlation coefficient analysis. The experimental results showed that the oil recovery of hydrocarbon gas is higher than that of CO₂ and CH₄, which were 57, 51, and 18% respectively. This is mainly because hydrocarbon gas is similar to the components of crude oil and is more easily dissolved in crude oil. The experimental results of influencing factors showed that the higher the content of C₂-C₄, the higher the oil recovery, and the content of C₂-C₄ will affect its dissolution with crude oil and its interaction with heavy component crude oil. The larger the permeability ratio, the lower the oil recovery, which was mainly due to the uneven distribution of injected gas in different regions. The higher the permeability, the lower the oil recovery, which was also due to the serious heterogeneity of the low permeability core of Niuquanhu; The results of Spearman rank correlation coefficient analysis based on different influencing factors and oil recovery showed that the order of influence of different factors on oil recovery was C₂-C₄ content > permeability ratio > permeability > back pressure > gas injection rate. In the development process of hydrocarbon gas injection, we should control the C₂-C₄ content, back pressure, and injection rate. The research in this study not only provides theoretical support for gas injection enhanced oil recovery technology in "low permeability and medium viscosity crude oil" reservoirs but also provides a new idea for the ranking of influencing factors.