Synergistic Modes and Enhanced Oil Recovery Mechanism of CO 2 Synergistic Huff and Puff

Ganggang Hou, Xiaoli Ma, Wenyue Zhao, Pengxiang Diwu, Tongjing Liu and Jirui Hou
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Ganggang Hou: Unconventional Oil and Gas Institute, China University of Petroleum (Beijing), Beijing 102249, China
Xiaoli Ma: Jidong Oilfield Company Ltd. Exploration and Development Research Institute, Tangshan 063000, China
Wenyue Zhao: Unconventional Oil and Gas Institute, China University of Petroleum (Beijing), Beijing 102249, China
Pengxiang Diwu: College of Science, China University of Petroleum (Beijing), Beijing 102249, China
Tongjing Liu: Unconventional Oil and Gas Institute, China University of Petroleum (Beijing), Beijing 102249, China
Jirui Hou: Unconventional Oil and Gas Institute, China University of Petroleum (Beijing), Beijing 102249, China

Energies, 2021, vol. 14, issue 12, 1-30

Abstract: With the gradual declining of oil increment performance of CO 2 huff-and-puff wells, the overall oil exchange rate shows a downward tendency. In this regard, CO 2 synergistic huff-and-puff technologies have been proposed to maintain the excellent effect and extend the technical life of such wells. However, there is no specific research on the mechanism and synergistic mode of CO 2 huff and puff in horizontal wells. This study aims to establish the synergistic mode and determine the adaptability and acting mechanism of CO 2 synergistic huff and puff. Three synergistic huff-and-puff modes are proposed based on the peculiarity of the fault-block reservoir’s small oil-bearing area and broken geological structure. We establish three typical CO 2 synergistic huff-and-puff models and analyze the influence of different geological and development factors on the huff-and-puff performance with numerical simulation. Each factor’s sensitivity is clarified, and the enhanced oil recovery (EOR) mechanism of CO 2 synergistic huff and puff is proposed. The sensitivity evaluation results show that the reservoir rhythm, inter-well passage, well spacing, high-position well liquid production rate, and middle-well liquid production rate are extremely sensitive factors; the stratum dip and injection volume allocation scheme are sensitive factors; and the relationship with structural isobaths is insensitive. The EOR mechanism of synergistic huff and puff includes gravity differentiation, supplementary formation energy, CO 2 forming foam flooding, and coupling effect of production rate and oil reservoirs. The implementation conditions of the two-well cooperative stimulation mode are the simplest. The two-well model is suitable for thick oil layers with a positive rhythm and large formation dip. The single-well mode requires no channeling between the wells, and the multi-well mode requires multi-well rows and can control the intermediate well’s fluid production rate. Field application at C2X1 block shows a good performance with a total oil increment of 1280 t and an average water-cut reduction of 57.7%.

Keywords: CO 2 synergistic huff and puff; complex fault-block reservoir; synergistic mode adaptability; sensitivity analysis; EOR mechanism (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2021
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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