Safe pressure for hydrogen storage in subsurface

Abstract

Hydrogen exhibits interesting behavior that has intrigued many researchers in the last few years. It also provides a promising option for reducing carbon dioxide emissions but requires large storage as an energy carrier. In this study, we determine the safe pressure for hydrogen storage in a gas reservoir, so the fugitive and odorless molecules do not leak from the structural trap. For this reason, we propose a relation for estimating the safe pressure and quantify its uncertainty using Monte Carlo simulation. The uncertainty quantification is crucial because of the limited information available in this evolving field. We also adopt an Artificial Neural Network (ANN) approach to present the interfacial tensions of hydrogen systems for various pressures and temperatures. This study applies the proposed relation to the Ann Mag field near Corpus Christi in Texas and discusses complexities that arise in practice. It shows that the structural trap can sustain hydrogen pressure up to 8,438 psi at 10,239 ft and 10,515 psi at 12,020 ft below the surface. Higher pressures may lead to leakage because of fault slippage or fracture propagation. This study presents the heat maps of the interfacial tensions that are convenient tools for analyzing hydrogen transport. The proposed relation also has applications in the safe storage of hydrogen in geological formations.

Keywords

• Underground hydrogen storage
• Structural trapping
• Artificial Neural Network (ANN)
• Monte Carlo simulation