Room-scale CO2 injections in a physical reservoir model with faults

TL;DR

This study conducts repeated room-scale CO2 injection experiments in a faulted geological model to analyze storage capacity, security, and reproducibility, revealing high consistency in homogeneous areas and fault-related variability.

Contribution

It provides a detailed physical and quantitative analysis of CO2 sequestration processes and introduces a reproducibility assessment in faulted geological models.

Findings

High reproducibility in homogeneous regions (up to 97%)

Fault heterogeneity reduces experimental reproducibility

Observed oscillating CO2 leakage behavior at an open anticline

Abstract

We perform a series of repeated CO2 injections in a room-scale physical model of a faulted geological cross-section. Relevant parameters for subsurface carbon sequestration, including multiphase flows, capillary CO2 trapping, dissolution, and convective mixing, are studied and quantified. As part of a forecasting benchmark study, we address and quantify six predefined metrics for storage capacity and security in typical CO2 storage operations. Using the same geometry, we investigate the degree of reproducibility of five repeated experimental runs. Our analysis focuses on physical variations of the spatial distribution of mobile and dissolved CO2, multiphase flow patterns, development in mass of the aqueous and gaseous phases, gravitational fingers, and leakage dynamics. We observe very good reproducibility in homogenous regions with up to 97 % overlap between repeated runs, and that fault-related heterogeneity tends to decrease reproducibility. Notably, we observe an oscillating anticline CO2 leakage behavior from an open anticline with a spill point in the immediate footwall of a normal fault, and discuss the underlying causes for the observed phenomenon within the constraints of the studied system.