PNNL

Abstract

This paper explores the impact of the temporally dynamic demand for CO2 for enhanced hydrocarbon recovery with CO2 storage. Previous evaluations of economy-wide CO2 capture and geologic storage (CCS) deployment have typically applied a simplifying assumption that 100% of the potential storage capacity for a given formation is available on the first day of the analysis, and that the injection rate impacts only the number of wells required to inject a given volume of fluid per year, making it a cost driver rather than a technical one. However, as discussed by Dahowski and Bachu [1], storing CO2 in a field undergoing CO2 flooding for enhanced oil recovery (EOR) is subject to a set of constraints to which storage in DSFs is not, and these constraints combined with variable demand for CO2 may strongly influence the ability of an EOR field to serve as a baseload storage formation for commercial scale CCS projects undertaken as a means of addressing climate change mitigation targets. This analysis assumes that CCS is being undertaken in order to reduce CO2 emissions from the industrial sources evaluated and that there is enough of a disincentive associated with venting CO2 to the atmosphere that any CO2 not used within the EOR field will be stored in a suitable nearby deep saline formation (DSF). The authors have applied a CO2 demand profile to two cases chosen to illustrate the differences in cost impacts of employing EOR-based CCS as a part of a given source’s CCS portfolio. The first scenario is a less-than-ideal case in which a single EOR field is used for storage and all CO2 not demanded by the EOR project is stored in a DSF; the second scenario is designed to optimize costs by minimizing storage in the DSF and maximizing lower-cost EOR-based storage. Both scenarios are evaluated for two facilities emitting 3 and 6 MtCO2/y, corresponding to a natural gas processing facility and an IGCC electric power plant, respectively. Annual and lifetime average CO2 transport and storage costs are presented, and the impact of added capture and compression costs on overall project economics is examined.