Xia Wei, Wang Yu-Bo, Wu Jiang-Tao, Zhang Tao, Gong Liang, Zhu Chuan-Yong
Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
College of New Energy, China University of Petroleum (East China), Qingdao 266580, China.
Int J Mol Sci. 2025 Jul 3;26(13):6402. doi: 10.3390/ijms26136402.
The impact of water on CO sequestration and enhanced oil recovery processes is significant. In this study, a CO-water-film-crude-oil-rock molecular system was established. Then, the influence of water-film thickness on the dissolution and dispersion of CO and crude oil under different temperature and pressure scenarios was examined through molecular dynamics simulations. The results indicate that water films hinder CO diffusion into the oil, reducing its ability to lower oil density. When the thickness of the water film increases from 0 nm to 3 nm, the oil density increases by 86.9%, and the average diffusion coefficient of oil decreases by 72.30%. Increasing the temperature enhances CO-oil interactions, promoting CO and water diffusion into oil, thereby reducing oil density. Under conditions of a 2 nm water film and 10 MPa pressure, increasing the temperature from 100 °C to 300 °C results in a decrease of approximately 32.1% in the oil density. Pressure also promotes oil and water-film density reduction, but its effect is less significant compared to temperature. These results elucidate the function of the water film in CO-EOR processes and its impact on CO dissolution and diffusion in water-bearing reservoirs.
水对二氧化碳封存和强化采油过程的影响显著。在本研究中，建立了一个二氧化碳 - 水膜 - 原油 - 岩石分子体系。然后，通过分子动力学模拟研究了在不同温度和压力条件下水膜厚度对二氧化碳和原油溶解与扩散的影响。结果表明，水膜阻碍二氧化碳向油中扩散，降低了其降低油密度的能力。当水膜厚度从0纳米增加到3纳米时，油密度增加86.9%，油的平均扩散系数降低72.30%。升高温度增强了二氧化碳与油的相互作用，促进二氧化碳和水向油中扩散，从而降低油密度。在2纳米水膜和10兆帕压力条件下，将温度从100℃升高到300℃，油密度降低约32.1%。压力也促进油和水膜密度降低，但其效果与温度相比不太显著。这些结果阐明了水膜在强化采油过程中的作用及其对含水库中二氧化碳溶解和扩散的影响。
