Microscopic remaining oil initiation mechanism and formation damage of CO2 injection after waterflooding in deep reservoirs

Xue Zhang, Yuliang Su, Lei Li, Qi'an Da, Yongmao Hao, Wendong Wang, Jiahui Liu, Xiaogang Gao, An Zhao and Kaiyu Wang

Energy, 2022, vol. 248, issue C

Abstract: Injecting CO2 into deep reservoirs with high temperature and pressure (HTHP) is a promising method for enhancing oil recovery (EOR) and CO2 utilization and storage (CUS). It is, however, challenging to quantitatively unravel the initiation mechanisms of micro-remaining oil and formation damage using microfluidic technology at 115 °C and 55 MPa. In this study, water/gas flooding experiments in the micromodel has carried out on the HPHT microfluidic experimental platform. The results reveal that 35.41% of the micro-remaining oil is recovered by scCO2 extraction on the funnel-shaped interface, and 11.21% by carbonated water swelling. When water is injected into heterogeneous reservoirs, the oil-water displacement front in the high-permeability zone is less stable than that in the low-permeability zone. Subsequent scCO2 injection resulted in asphaltene deposits (approximately 10.49% of pore volume), including low-velocity deposition, corner deposition and trap deposition, which reduced reservoir permeability. Moreover, compared with continuous CO2 injection, the asphaltene deposition is reduced by 4.25% of CO2 injection after waterflooding, including 2.64% in the high-permeability zone and 1.61% in the low-permeability zone. These observations provide important theoretical support for the application of CO2-EOR technology and carbon storage in deep reservoirs.

Keywords: Micro-remaining oil initiation mechanism; Multiphase flow characteristics in porous media; Asphaltene deposition; CO2-EOR; Unconventional deep reservoirs (search for similar items in EconPapers)
Date: 2022
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Citations: View citations in EconPapers (2)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:248:y:2022:i:c:s0360544222005527

DOI: 10.1016/j.energy.2022.123649

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