Feasibility and Influencing Factors of Miscible Hydrocarbon Gas Flooding for Deep Fractured-Vuggy Reservoirs

doi:10.7657/XJPG20210610

Abstract

Abstract:

In order to investigate the deep fractured-vuggy reservoir in Tahe oilfield, the minimum miscible pressure of hydrocarbon gas-crude oil system is calculated through indoor phase behavior experiments and using empirical formula method, pseudo-ternary phase diagram method and slim tube simulation method, and the influences of early nitrogen injection and crude oil quality on hydrocarbon gas miscible flooding are studied through numerical simulation. The research results show that the minimum miscible pressure calculated by the three methods is much lower than the average actual reservoir pressure, so hydrocarbon gas-crude oil miscible flooding is very feasible for the deep fractured-vuggy reservoir in the study area; and early nitrogen injection impacts the miscible flooding significantly. In the reservoir swept by injected nitrogen, the minimum hydrocarbon gas-crude oil miscible pressure becomes higher. In the reservoir where the ratio of nitrogen to hydrocarbon gas is greater than 1.208, a miscible phase wouldn’t appear. Crude oil quality also has a great impact on hydrocarbon gas-crude oil miscible flooding. The more the light components in crude oil, the lower the minimum miscible pressure of hydrocarbon gas and crude oil, and the more the heavy components in crude oil, the lower the ultimate recovery rate of the miscible flooding.

Key words: Tarim basin, Tahe oilfield, deep fractured-vuggy reservoir, hydrocarbon gas-crude oil miscible flooding, minimum miscible pressure, slim tube experiment, feasibility

CLC Number:

TE344

LI Jikang, SUN Zhixue, TAN Tao, GUO Chen, XIE Shuang, HAO Cong. Feasibility and Influencing Factors of Miscible Hydrocarbon Gas Flooding for Deep Fractured-Vuggy Reservoirs[J]. Xinjiang Petroleum Geology, 2021, 42(6): 714-719.

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