Volume 49

Flue Gas-Assisted Steam Flooding in Heavy Oil Reservoirs: Experimental Study and Numerical Simulation Tao SONG, Yiqiang LI, Jianqiang ZI, Jinxin CAO, Yaqian ZHANG, Xuechen TANG, Qihang LI, Xiaolong LV

Abstract

To address the issue of steam override and low oil-steam ratios in the middle to late stages of steam flooding development in heavy oil reservoirs, experiments and numerical simulation studies on flue gas-assisted steam flooding were conducted following steam flooding. This study investigates a heavy oil reservoir block in the Xinjiang Oilfield as its research subject and conducts one-dimensional core displacement experiments to comparatively analyze the impact of various injection media on oil displacement efficiency. The experimental results demonstrate that flue gas-assisted steam flooding can enhanced oil recovery by up to 5.84% in comparison to steam flooding. A mechanism model for flue gas-assisted steam flooding in heavy oil reservoirs with a five-spot well pattern was established based on a core numerical model calibrated to experimental data and supplemented by geological reservoir characteristics data. This model is used to systematically study the mechanism and effect of the above methods in heavy oil reservoir development. The results indicated that flue gas-assisted steam flooding is an effective technique to enhance the oil recovery. Injected flue gas not only increases the contact time between steam and crude oil but also mitigates steam override and expand steam sweep range. Oil recovery improvement is significant when the steam to flue gas molar fraction ratio is 8:2, and oil recovery is 63.36%. The results of the injection mode study show that slug injection facilitates superior steam penetration into the lower reservoir compared to continuous injection. At this moment, the periodic pressure difference formed in the reservoir can improve the efficiency of the oil displacement. The study findings could be valuable in designing flue gas-assisted steam flooding for heavy oil reservoirs.

Keywords steam flooding, flue gas, heavy oil, displacement test, numerical simulation, enhanced oil recovery