Serious concerns exist about the economic feasibility of underground hydrogen (H2) storage (UHS) in aquifers. The authors’ objective is to investigate the use of an optimization workflow to maximize both H2 storage and net present value (NPV), consequently obtaining an optimal reservoir development strategy.
Introduction
An aquifer storage system for H2 typically consists of a brine-saturated formation layer, injection and withdrawal wells, and surface pipelines. The injected gas is divided into cushion gas (usually H2 or another gas) and working gas (H2). The main purpose of the cushion gas is to maintain sufficient minimum pressure, while the working gas is aimed at temporary storage and later production and sale. During UHS, the working gas is injected into the subsurface and then mixed with the formation fluid and extracted in a cyclical manner.
