Study on Heat Self-generated Mixed-gas Assisted Steam Huff-n-Puff for Enhance Heavy Oil Recovery

ABSTRACT

In this paper, based on the in-situ generation technology and the advantage of non-condensate gas (N₂ and CO₂)-assisted steam huff-n-puff, a new technology of heat self-generated mixed-gas (HSGMG)-assisted steam huff-n-puff is proposed, which can further enhance heavy oil recovery by using different gas-assisted steam huff-n-puff. Based on the optimization of HSGMG agent solution, the reliability and relative error of the experimental results and calculated pressurization effect were evaluated, and its heavy oil viscosity reduction rate (HOVRR) was investigated. Results showed that the experiments were reliable, and its relative error was small. The calculated pressurization effect indicated that formation energy could be supplemented. Its HOVRR was very significant above 90°C. The oil displacement efficiency of this technology was further examined by sand-pack huff-n-puff test under different conditions. The results indicated that a higher total molar concentration, a larger slug size, and a faster pressure depletion rate contributed to improved oil displacement efficiency, but the economic indicator was reduced. When the total injection volume was constant, this efficiency of huff-n-puff with different injection patterns was little different.

Abbreviation: DDTFW: diluted different times formation water; EHOR: enhanced heavy oil recovery; HOVRR: heavy oil viscosity reduction rate; HSGMG: heat self-generated mixed-gas; HTPR: high temperature and pressure reactor; IFP: initial formation pressure; IP: initial pressure; IOR: incremental oil recovery; L-P: lipid molar proportion; PDR: different pressure depletion rate; PST: pressure stabilization time; RT: reaction temperature; TIOR: total incremental oil recovery; TMC: total molar concentration.

KEYWORDS:

• Heavy crude oil
• sand-pack huff-n-puff
• heat self-generated mixed-gas agent
• EOR
• viscosity reduction rate

Acknowledgments

We also acknowledge the Provincial Key Laboratory of Unusual Well Stimulation at Xi’an Shiyou University for the permission to publish this paper.

Competing interests

The authors declare no competing interests.

Additional information

Funding

The research was supported by the National Natural Science Foundation Projects of China (51304159 and 51174163), China Petroleum Major Project (2016ZX05050-009), and Scientific Research Program Funded by Shaanxi Provincial Education Department (18JS086).

Notes on contributors

Qin Guowei

Qin Guowei is an associate professor at College of Petroleum Engineering of Xi’an Shiyou University. He previously served as apetroleum engineer at E&D Research Institute of Daqing Oilfield Co Ltd..He holds a PhD in petroleum from China University of Petroleum(Eastern).

Wu Mei

Wu Mei is apetroleum engineer at E&D Research Institute of PetroChina Research Institute. She holds a MS in petroleum from Northeast Petroleum University.

Li Wenfang

Li Wenfang is apetroleum engineer at E&D Research Institute of Changqing Oilfield Company. She holds a MS in petroleum from Xi’an Shiyou University.

Qin Wenlong

Qin Wenlong is an associate professor at College of Petroleum Engineering of Xi’an Shiyou University. He holds a PhD in geology from Northeast University.

You Qing

You Qing is an associate professor at School of Energy Resource of China University of Geoscience(Beijing).He holds a PhD in petroleum from China University of Petroleum(Eastern).

Jin Wenbo

Jin Wenbo is a lecturer at College of Petroleum Engineering of Xi’an Shiyou University. He holds a PhD in geology from Southwest Petroleum University.