Assessing the potential of CO2 huff ‘n’ puff technology for enhanced oil recovery and CO2 sequestration in tight oil reservoirs

Abstract Fossil fuels utilization will produce a large amount of CO 2 , which causes a series of environmental problems. However, the exhaust CO 2 can be used to achieve oil recovery improvement (CO 2 EOR), while simultaneously allowing for the geological storage of CO 2 . For the unconventional reservoir, CO 2 huff ‘n’ puff (HNP) is a potential technology showing promising results in laboratory experiments, while its effectiveness in enhancing oil recovery and CO 2 sequestration at the reservoir scale remains uncertain. Thus, further research is needed to evaluate the CO 2 HNP performance for its implementation. In this paper, we conducted a numerical simulation of the CO 2 HNP process in a real tight oil reservoir (1800 m × 350 m × 10m in size) to assess its potential for improving oil recovery, CO 2 injectivity, and CO 2 sequestration. The results show that the accumulative oil production increased by more than 20% after the implementation of CO 2 HNP. Meanwhile, CO 2 HNP in tight oil reservoirs is proven capable to achieve CO 2 injectivities of more than 4×10 7 SCm 3 and CO 2 storages of more than 5×10 6 SCm 3 . We designed 3 CO 2 HNP schemes and found that the largest CO 2 storage does not occur in the optimal scenario for oil production. A new type of CO 2 HNP evaluation system considering oil production and storage capacity needs to be established. The results of the article suggest that CO 2 HNP can achieve an oil production increase and CO 2 storage in tight reservoirs, which has a positive significance for the sustainable development of environmental protection.