Experimental and numerical investigation of supercritical CO2 migration in sandstone with multiple clay interlayers. (January 2021)

• Record Type: Journal Article
• Authors: Xu, Liang; Li, Qi; Myers, Matthew; White, Cameron; Tan, Yongsheng
• Is Part Of: International journal of greenhouse gas control. Volume 104(2021)
• Publication Date: 2021-01
• Subjects: CO2-EWR -- Anisotropic sandstone -- Multiple clay interlayers -- Core flooding experiment -- Numerical simulation; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2020.103194
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: Typical reservoir sandstone with multiple clay interlayers is used. A high-resolution X-CT scanner is used to visualize the fluid behavior during the drainage processes. A 2D model based on Darcy flow is developed to analyze fluid migration. The main factors affecting behavior of CO2 during drainage are analyzed. The reasons for the difference between experimental and simulation results are listed. Abstract: CO2 enhanced water recovery (CO2 -EWR) is one of the most promising technologies for geologic carbon sequestration. The migration characteristics and displacement efficiency of supercritical CO2 (SC-CO2 ) after injection into a saline aquifer directly affect the feasibility and economy of a CO2 -EWR project. Multiple clay interlayers often develop in the target sandstone reservoir and combine in different expansive ways, which could influence the SC-CO2 migration. In this study, core flooding experiments were conducted using a special sandstone with multiple thin clay interlayers and the fluid behavior was monitored by an X-ray computed tomography (X-CT) scanner. Based on the porosity matrix obtained from X-CT images, a two-dimension model based on Darcy flow was developed to simulate the fluid behavior under the experiment conditions. The experimental results show that SC-CO2 pathways were developed in the sand part of the sample, while the clay interlayers were fluid-proof. Comparing the experimental and simulation results, it is evident that the porosity distribution, clay interlayers directionality/extent and flooding direction were the main factors that affected the fluid behavior in the sample. There were positive correlations between porosity and SC-CO2 saturation after drainage processes. Flooding directions and clay interlayers were combined to affect the fluid migration. The clay interlayers had functions of barrier and collection when the flooding direction pointed towards the opening of a wedge-shaped semi-open area formed by clay interlayers. While this area was almost free of SC-CO2 when the injection direction reversed, resulting a smaller SC-CO2 saturation in sample during the backward drainage process.