多孔介质中含溶解-沉淀的多场耦合反应过程孔隙尺度模拟研究

Multiple physicochemical coupled reactive transport processes involving dissolution and precipitation occurring in porous media are often encountered in energy and environmental disciplines, such as CO2 subsurface sequestration, shale gas/oil exploitation and oil well acidizing. Several physicochemical phenomena are involved in such reactive transport processes and the coupling mechanisms between different phenomena are non-linear and significantly complicated. Investigation of such processes is of great theoretical significance and academic value, and can provide theoretic foundation for practical engineering. In the present project, pore-scale numerical method will be employed to simulate the above processes, understand the reactive transport phenomena and reveal the coupled mechanism. First, reconstruction algorithm will be developed to reconstruct the complex microscopic porous structures of the porous media and the topologies of multiple elements in the solid phase. Second, pore-scale numerical method will be established, which takes into account multiple physicochemical processes including fluid flow, multi-component mass transport, homogeneous and heterogeneous reactions, and solid phase dissolution and precipitation. Third, dissolution processes in porous media with multiple mineral elements will be studied. Dissolution patterns, statistic structural parameters and macroscopic transport properties under different reactive transport condition, different content and topologies of the un-dissolving mineral will be determined. Fourth, interface coupled dissolution-reaction processes will also be simulated. Effects of reaction kinetic parameters, physical properties of the primary dissolving phase and the secondary precipitating phase, and crystal growth mechanism on the dissolution-precipitation processes will be investigated. Finally, the simulation will be extended to multiphase reactive transport system. Distributions of the two-phase flow under different surface wettabilities will be predicted, and their effects on the dissolution of solid phase will be assessed.

在能源与环境学科中，多孔介质中含溶解-沉淀的多场耦合反应输运过程非常常见，如CO2地质封存，页岩油气开发以及油井酸化等。其含物理化学过程众多，过程间非线性耦合机制复杂，对其研究具有重要理论意义和学术价值，为工程实际提供理论基础。本项目发展孔隙尺度数值方法研究该过程，揭示过程机理和过程间耦合机制。具体工作包括：发展结构重构算法，重构多孔介质复杂微观结构和固相中多矿物成分分布；发展和完善考虑流动、多组分传质、均相（非均相）反应以及固体溶解-沉淀的孔隙尺度数值模拟方法；研究含多矿物成分的多孔介质溶解过程，查明不同反应输运条件、不溶矿物含量和形态对溶解过程、结构参数和输运系数的影响；研究界面耦合的溶解-沉淀过程，探明反应输运条件、原生溶解相和次生沉淀相物性参数、晶体生长方式等因素对溶解-沉淀的影响；研究多相反应输运过程，揭示多孔介质润湿特性对两相分布型态以及固体溶解的影响规律。

针对多孔介质中含溶解-沉淀的多物理化学场耦合反应输运过程，项目发展了若干多孔介质结构重构及表征方法，基于介尺度数值方法格子Boltzmann方法及流固界面追踪技术，构建了针对多孔介质中复杂多场耦合传递过程的先进孔尺度数值仿真方法，并深入研究了多孔介质中发生的多相流、传质、化学反应、固体溶解-沉淀的多场耦合过程，查明了反应输运条件及多孔介质各向异性结构及成分分布对输运过程及输运关系函数的影响。项目发展的针对多孔介质中复杂多场耦合传递过程的先进孔尺度数值仿真方法被国内外同行积极评价。共发表标注基金号SCI论文15篇。其中第一作者SCI论文7篇，通讯作者SCI论文3篇，合作作者SCI论文4篇。一篇第一作者SCI论文入选ESI高被引论文，一篇合作作者论文入选ESI高被引论文。共参加国际会议5次，国内会议2次，受邀请在国际会议上做邀请报告2次，国内会议邀请报告1次。培养博士生1名，已经获博士学位1名，还有1名博士论文正在完成中。