Assessing the economic feasibility of regional deep saline aquifer CO 2 injection and storage: A geomechanics-based workflow applied to the Rose Run sandstone in Eastern Ohio, USA

Abstract

Typical top-down regional assessments of CO 2 storage feasibility are sufficient for determining the maximum volumetric capacity of deep saline aquifers. However, they do not reflect the regional economic feasibility of storage. This is controlled, in part, by the number and type of injection wells that are necessary to achieve regional CO 2 storage goals. In contrast, the geomechanics-based assessment workflow that we present in this paper follows a bottom-up approach for evaluating regional deep saline aquifer CO 2 storage feasibility. The CO 2 storage capacity of an aquifer is a function of its porous volume as well as its CO 2 injectivity. For a saline aquifer to be considered feasible in this assessment it must be able to store a specified amount of CO 2 at a reasonable cost per ton of CO 2. The proposed assessment workflow has seven steps that include (1) defining the storage project and goals, (2) characterizing the geology and developing a geomechanical model of the aquifer, (3) constructing 3D aquifer models, (4) simulating CO 2 injection, (5,6) evaluating CO 2 injection and storage feasibility (with and without injection well stimulation), and (7) determining whether it is economically feasible to proceed with the storage project. The workflow was applied to a case study of the Rose Run sandstone aquifer in the Eastern Ohio River Valley, USA. We found that it is feasible in this region to inject 113 Mt CO 2/year for 30 years at an associated well cost of less than US $1.31/t CO 2, but only if injectivity enhancement techniques such as hydraulic fracturing and injection induced micro-seismicity are implemented.