Evaluating Reservoir Suitability for Large-scale Hydrogen Storage: A Preliminary Assesment Considering Reservoir Properties

With rising demand for clean energy, global focus turns to finding ideal sites for large-scale underground hydrogen storage (UHS) in depleted petroleum reservoirs. A thorough preliminary reservoir evaluation before hydrogen (H2) injection is crucial for UHS success and safety. Recent criteria for UHS often emphasize economics and chemistry, neglecting key reservoir attributes. This study introduces a comprehensive framework for the reservoir-scale preliminary assessment, specifically tailored for long-term H2 storage within depleted gas reservoirs. The evaluation criteria encompass critical components, including reservoir geometry, petrophysical properties, tectonics, and formation fluids. To illustrate the practical application of this approach, we assess the Barnett shale play reservoir parameters. The assessment unfolds through three key stages: (1) A systematic evaluation of the reservoir's properties against our comprehensive screening criteria determines its suitability for H2 storage. (2) Using both homogeneous and multilayered gas reservoir models, we explore the feasibility and efficiency of H2 storage. This phase involves an in-depth examination of reservoir behavior during the injection stage. (3) To enhance understanding of UHS performance, sensitivity analyses investigate the impact of varying reservoir dimensions and injection/production pressures. The findings reveal the following: (a) Despite potential challenges associated with reservoir compaction and aquifer support, the reservoir exhibits substantial promise as an H2 storage site. (b) Notably, a pronounced increase in reservoir pressure manifests during the injection stage, particularly in homogeneous reservoirs. (c) Furthermore, optimizing injection-extraction cycle efficiency can be achieved by augmenting reservoir dimensions while maintaining a consistent thickness. To ensure a smooth transition to implementation, further comprehensive investigations are advised, including experimental and numerical studies to address injectivity concerns and explore storage site development. This evaluation framework is a valuable tool for assessing the potential of depleted gas reservoirs for large-scale hydrogen storage, advancing global eco-friendly energy systems.