Modeling pressure and saturation distribution in a CO₂ storage project using a Surrogate Reservoir Model (SRM)

Capturing carbon dioxide (CO 2 ) from large point sources and depositing it in a geological formation is an efficient way of decreasing CO 2 concentration in the atmosphere. A comprehensive study is required to perform a safe and efficient CO 2 capture and storage (CCS) project. The study includes different steps, such as selecting proper underground storage and keeping track of CO 2 behavior in the storage environment. Numerical reservoir simulators are the conventional tools used to implement such an analysis. The intricacy of simulating multiphase flow, having a large number of time steps required to study injection and post‐injection periods of CO 2 sequestration, a highly heterogeneous reservoir, a large number of wells, etc., will lead to a complicated reservoir model. A single realization for such a reservoir takes hours to run. Additionally, a thorough understanding of the CO 2 sequestration process requires multiple realizations of the reservoir model. Consequently, using a conventional numerical simulator makes the computational cost of the analysis too high to be practical. In this paper, we examine the application of a relatively new technology, the Surrogate Reservoir Model (SRM), as an alternative tool to solve the aforementioned problems. SRM is a replica of full‐field reservoir simulation models. It can generate outputs in a very short time with reasonable accuracy. These characteristics make SRM a unique tool in CO 2 sequestration modeling. This paper proposes developing an SRM for a CO 2 sequestration project ongoing in the SACROC unit to model pressure behavior and phase saturation distributions during different time steps of the CO 2 storage process.