Journal of Southwest Petroleum University(Science & Technology Edition) ›› 2025, Vol. 47 ›› Issue (4): 137-145.DOI: 10.11885/j.issn.1674-5086.2022.06.21.02

• OIL AND GAS ENGINEERING • Previous Articles     Next Articles

Adsorption Characteristics of Fluid in the Reservoir of Wells Injected Alternately by Supercritical Carbon Dioxide and Water

BAI Yujie, WEI Haodong, NAN Xiaohan   

  1. MOE Key Laboratory for Oil and Gas Recovery Improvement, Northeast Petroleum University, Daqing, Heilongjiang 163318, China
  • Received:2022-06-21 Published:2025-07-25

Abstract: In order to study the adsorption characteristics of fluid in the reservoir of wells injected alternately by supercritical carbon dioxide and water, the microstructure and mineral composition of reservoir rocks were analyzed. The molecular model of stratum rock structure was established to study the fluid adsorption characteristics of different clay minerals, and the competitive adsorption and influencing factors of different fluids on the rock surface were analyzed. The results showed that the compact rocks of Yushulin oil layer in Daqing Oilfield are composed of silica matrix and clay minerals such as kaolinite and montmorillonite. The adsorption capacity of reservoir minerals for light hydrocarbons was greater than that for heavy hydrocarbons, and adsorption capacity for water and carbon dioxide was greater than that for hydrocarbons. Silicon dioxide had the strongest adsorption capacity for water and carbon dioxide, indicating that the oil recovery of the reservoir dominated by silicon dioxide was higher by using alternate injection flooding of supercritical carbon dioxide and water. Intermittent stop injection could make carbon dioxide easier to enter into rock samples and make crude oil easier to discharge. The higher temperatures accelerate the exchange of crude oil, water and carbon dioxide molecules. Under high pressure, carbon dioxide reacts with crude oil on the rock surface to change the properties of crude oil, thereby increasing the oil removal rate.

Key words: competitive adsorption, tight oil, supercritical carbon dioxide, water-gas alternate flooding, molecular dynamics

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