Investigations of CO2 flow and transport processes in high pressure gas injections (100 bar) using micro-computer tomography, representative micro-models and numerical models

地下二氧化碳气体储存（CCS）是气候友好型能源政策的重要选择。另一方面，必须通过使用CO2气体注入的“增强”石油生产（EOR）来保证能源安全。在该研究项目的框架内，使用µ-计算机断层扫描（CT）和代表性微观模型在高压气体注入（100 bar）期间研究重要的CO2流动和传输过程。为此，将为柱和微模型实验建立一个高压测量站（高达100 bar）。主要目的是验证先前的μ-CT和微观模型研究的结果，在高压条件下的润湿性和表面粗糙度对多相流模式的影响，并发现新的压力依赖性现象。CO2、水和油用作流体，玻璃珠沉积物、细砂和砂岩用作多孔介质。润湿性通过硅烷化或合适的流体-流体对来控制。基本感兴趣的问题是，是否可以描述多相流行为和通用标度的集群大小分布和什么样的影响，孔结构，固体表面的微观结构和非均匀润湿性的流型和捕获过程。为了理解气体形成过程，重要的是要比较压力依赖的CO2传输（扩散，传质）在均匀和非均匀的热力学系统。被水或油饱和的多孔介质被用作非均质系统。在方法上，利用微CT和图像分析技术对储层孔隙结构和孔隙空间拓扑结构进行了分析和量化，利用聚类分析技术对捕集流体团簇的几何形状和静态分布进行了分析和量化。捕获过程的动力学进行了研究，使用光学可视化与高分辨率SLR相机或荧光显微镜的代表性的2D-Si-micromodels与控制壁粗糙度。预期的结果是基本的利益，以及极大的实际意义，因为它们提高了理解的孔隙尺度过程，从而有助于CCS和EOR。

Underground CO2-gas storage (CCS) is an important option for a climate-friendly energy policy. On the other hand, energy security must be guaranteed through "enhanced" oil production (EOR) using CO2 gas injection. Within the framework of the research project, important CO2-flow- and transport processes are investigated during high-pressure gas injections (100 bar) using µ-Computer Tomography (CT) and representative micromodels. For this purpose, a high-pressure measuring station (up to 100 bar) will be set up for both column and micro-model experiments. The main objective is to verify the results of previous μ-CT- and micromodel studies on the influence of wettability and surface roughness on multiphase flow patterns under high-pressure conditions and to discover new pressure-dependent phenomena. CO2, water and oil are used as fluids and glass beads sediments, fine sands and sandstones as porous media. The wettability is controlled by means of silanization or suitable fluid-fluid pairs. Of fundamental interest are the questions, whether percolation can describe the multiphase flow behavior and universal scaling the cluster size distribution and what influence, pore structure, microstructure of the solid surface and heterogeneous wettability have on the flow pattern and the trapping process. To understand the gas formation processes, it is important to compare pressure-dependent CO2 transport (diffusion, mass transfer) in homogeneous and heterogeneous thermodynamic systems. Porous media saturated with water or oil are used as heterogeneous systems. Methodologically, the pore structure and pore space topology are analyzed and quantified by means of µ-CT and image analysis, and the geometry and static distribution of trapped fluid clusters by means of cluster analysis. The dynamics of the trapping process are investigated using optical visualization with a high-resolution SLR camera or fluorescence microscopy of representative 2D-Si-micromodels with controlled wall roughness. The expected results are of fundamental interest as well as of great practical relevance, as they improve the understanding of the pore scale processes and thus contribute to CCS and EOR.