Application of a dual tubing CO2 injection-water production horizontal well pattern for improving the CO2 storage capacity and reducing the CAPEX: A case study in Pohang basin, Korea

Abstract Water production is an efficient way of relieving pressure build-up and improving the CO2 storage capacity (CSC) in the carbon capture and storage process. The additional offshore platforms, production wells, pipelines, and pumps required for water production, however, increase the capital expenditure (CAPEX) of the project. Therefore, a CO2 injection method that can both improve the CSC and reduce the CAPEX is needed. This paper proposes a dual-tubing CO2 injection-water production horizontal well (DTHW) pattern for improving the CSC, in which CO2 is injected at the heel of the horizontal well while water is produced at the toe. The CSC and CAPEX of the proposed DTHW pattern were then compared to those of other cases in a saline aquifer in the Pohang basin, offshore Korea. The CCSPerformance (CSC to CAPEX ratio) of the proposed DTHW pattern was larger than that of a typical CO2 injection with a water production pattern for the all CO2 injection-water production rate cases. The proposed DTHW pattern showed promising results in that the maximum CSC was improved by 98.2% compared to a single vertical CO2 injection well pattern and the CAPEX was reduced by 37.1% compared to the typical CO2 injection with a water production pattern. More CAPEX might be saved if a DTHW pattern is used in an onshore platform near a power plant because an additional offshore platform and pipeline are not required.