Experimental Study on Supercritical CO<sub>2</sub> Huff and Puff in Tight Conglomerate Reservoirs
Haiming Gao, Wanfen Pu
Abstract
A tight conglomerate reservoir is a kind of unconventional reservoir with strong heterogeneity, and CO2 injection is an economical and environmentally friendly method to enhance tight oil recovery. Supercritical CO2 is a very promising fluid medium for unconventional reservoir development due to its gas–liquid dual properties. In this study, the production effects of supercritical CO2 and non-supercritical CO2 in tight conglomerate reservoirs were quantitatively analyzed by huff and puff simulation experiments conducted under reservoir conditions (formation pressure 37 MPa, temperature 89 °C). Also, the influencing factors of CO2 huff and puff production, including injection volume, soaking time, and throughput cycles, were investigated. The results showed that supercritical CO2 improves the recovery by 4.02% compared with non-supercritical CO2. It could be seen that supercritical CO2 plays a positive role in improving tight conglomerate reservoirs. The optimal injection volume, soaking time, and throughput cycles were determined to be 0.50 PV, 2 h, and 3 cycles, respectively. This paper provides an important basis for the study of supercritical CO2 production in tight conglomerate reservoirs.