ABSTRACT

Lochard Energy, supported by research from CSIRO’s Energy Division, is investigating the feasibility of geological underground hydrogen storage (UHS) in depleted gas fields within the onshore Otway Basin, Victoria. Lochard’s H2RESTORE Project aims to use electricity sourced from the National Electricity Market (likely during periods of high renewable energy generation and low energy demand) to make hydrogen, store it underground as long duration energy storage and then reuse it to generate electricity when demand is high. This paper presents a general overview of a two-stage UHS reservoir modelling approach for porous sandstone reservoirs at two depleted gas fields with contrasting trap geometries and storage objectives. Stage 1 includes the static model building, subsequent dynamic model history matching and conversion to a full compositional model. Stage 2 involves the UHS well placement, setting of hydrogen cycling targets and constraints, initial filling scenario testing and hydrogen cycling analyses. Modelling at Field A was aimed at demonstrating the technical case for UHS feasibility at low hydrogen injection volumes for a pilot project, with acceptable hydrogen purity on production over a minimum number of cycles. Modelling at Field B was designed to demonstrate that a seasonal energy demand profile could be met over a 10-year period within the usual commercial operational constraints associated with cycling gas in underground porous reservoirs. Simulation results were able to demonstrate that hydrogen could be successfully injected and withdrawn at suitable production rates and purity to meet the project objectives at each of the fields.