复杂地层内CO2溶解对流过程物化耦合两相流动特征及机理研究

为探索CO2地质封存中真实地层环境下的两相流动过程，本项目将研究超临界CO2注入复杂地层后，考虑化学反应影响的部分溶解诱导对流流动特征及机理。研究内容为：（1）搭建非均匀Hele-Shaw cell实验系统，开展不同地层内CO2溶于盐水诱导对流实验；构建超临界CO2与盐水“部分互溶”过程的两相流动模型，开展不同地层内部分溶解对流的直接数值模拟，研究地层结构对流动特征及CO2溶解特性的影响；（2）通过实验和耦合化学反应的数值方法，开展不同地层环境下部分溶解对流物化耦合流动研究，明晰化学反应对流动特性、地层渗透率等的影响；（3）基于实验和数值结果，构建CO2在不同地层环境下溶解速率和封存量的时变模型、羽流尺度和对流强度的量化模型，揭示CO2地质封存中部分溶解对流过程物化耦合两相流动机理。本项目的研究成果将为CO2地质封存具体实施提供理论支持，促进CO2减排工程科学发展。

In order to investigate the two-phase flow process of CO2 geological sequestration in realistic stratigraphic environment, this program is proposed to study the flow feature and mechanism of the chemical reaction influence included partially-dissolving-driven convection flow, after the supercritical CO2 is injected into complex stratum. The research content includes: (1) Building heterogeneous Hele-Shaw cell experimental system to conduct the convection driven by CO2 dissolving into brine in different stratum. Establishing two-phase flow model for “partially miscible” process of supercritical CO2 and brine to achieve direct numerical simulation of partially-dissolving-driven convection in different stratum and study the influence of stratum construction on flow characteristic and dissolving peculiarity. (2) Employing experiment and chemical reaction coupling numerical method to study physical and chemical coupling flow of partially-dissolving-driven convection in different stratum environment and make sure the influence of chemical reaction on flow characteristic and stratum permeability. (3) Combining experiment and numerical simulation results, to build the time-varying model for CO2 dissolution rate and sequestration and quantitative model of plume scale and convection intensity in various stratum environment, and reveal mechanism of physical and chemical coupling two-phase flow for partially-dissolving-driven convection flow in CO2 geological sequestration. The achievement of this program will provide theoretical support for concrete implement of CO2 geological sequestration and promote the scientific development of CO2 emission reduction.