Guidelines for Reservoir Modeling of Geologic CO2 Storage

Abstract

The process of identifying suitable sites for storage of CO2 in deep saline formations involves methodical and careful analysis of the technical and non-technical features of potential storage areas. This process is largely analogous to that used in the petroleum industry through which a project matures from an exploration project to a producing project. The goal is to ensure that CO2 can be successfully and securely stored over extended periods of time in a manner that is compliant with the best engineering and geological practices, applicable regulations, and the best interests of local and regional stakeholders. Dynamic reservoir modeling is a key component of the process at all stages, from initial site screening and selection, through development planning, project implementation and operation, to site closure and post-injection monitoring. This paper summarizes guidelines for dynamic reservoir modeling of CO2 storage in deep saline formations. The guidelines draw heavily upon existing petroleum industry best practices for reservoir modeling of conventional oil and gas developments, but also consider modeling issues raised by the CO2 storage research community and historical CO2 and acid gas injection experience. Topics discussed include: Physical and chemical processes that need to be considered Project design options to manage CO2 plume growth and promote safe, efficient, and reliable storage in different geologic settings Design of models to address specific issues such as injectivity, storage capacity and security, and the long-term fate of the CO2 Although reservoir modeling has applications across all phases of a CO2 storage project, this paper focuses on modeling activities specific to site selection and development planning that are aimed at identifying suitable candidate sites having sufficient storage resource, confining formations, and the capability to retain the injected CO2 over hundreds of years. Modeling results are also used to assist several additional activities including: calculation of the Area of Review for monitoring of CO2 plume migration and pressure buildup, determination of the most advantageous injection intervals and operation parameters to maximize injectivity and storage efficiency, assessment of potential leakage pathways, mitigation options, and risk evaluation.