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，必须通过二氧化碳注气“提高”采油（EOR）来保证能源安全。在研究项目的框架内，利用微计算机断层扫描（CT）和代表性微观模型，研究了高压气体注入（100 bar）过程中重要的二氧化碳流动和输送过程。为此，将建立一个高压测量站（高达100 bar），用于柱和微模型实验。主要目的是验证以前的μ-CT和微模型研究的结果，即润湿性和表面粗糙度对高压条件下多相流流型的影响，并发现新的压力相关现象。二氧化碳、水和油作为流体，玻璃珠沉积物、细砂和砂岩作为多孔介质。润湿性由硅烷化或合适的流体-流体对控制。渗流是否能够描述多相流行为和普遍标化簇大小分布，以及孔隙结构、固体表面微观结构和非均质润湿性对流动模式和俘获过程有何影响，这些都是最基本的问题。为了理解气体的形成过程，比较均匀和非均匀热力学系统中与压力相关的二氧化碳传输（扩散、传质）是很重要的。饱和水或油的多孔介质用作非均相系统。在方法上，通过微ct和图像分析对孔隙结构和孔隙空间拓扑进行了分析和量化，并通过聚类分析对捕获流体簇的几何和静态分布进行了分析。利用高分辨率单反相机或荧光显微镜对具有代表性的具有控制壁粗糙度的2d - si微模型进行光学可视化研究。预期的结果不仅具有重要的实际意义，而且具有重要的基础意义，因为它们提高了对孔隙尺度过程的理解，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.