Biogeochemical Assessment of Short-Term Hydrogen Storage in Methane Reservoirs with Field Sample Characterization and...

Area of Science:

• Geochemistry
• Microbiology
• Energy Storage

Background:

• Hydrogen is a key energy carrier, with potential for storage in existing natural gas infrastructure.
• Biogeochemical processes impacting hydrogen/methane blends in reservoirs are not fully understood.
• Adapting methane storage for hydrogen requires investigating microbial and geochemical challenges.

Purpose of the Study:

• To identify geochemical and microbial challenges of storing hydrogen/methane blends in methane reservoirs.
• To characterize fluid samples and microbial communities from two U.S. western reservoirs.
• To perform short-term reactor experiments simulating natural gas and hydrogen blend storage.

Main Methods:

• Fluid sample collection and analysis (IC, ICP-OES, TOC analyzer).
• Microbial community analysis (16S rRNA gene amplicon sequencing, metagenomic sequencing).
• Short-term reactor experiments under reservoir conditions (80 °C, ~1000 psi) with biotic and abiotic controls.

Main Results:

• Reservoirs showed high total dissolved solids (TDS) and organic acids (acetate, propionate).
• Microbial communities possessed metabolic potential for sulfur reduction, iron reduction, and acetogenesis.
• Initial storage (days 1-3) resulted in minimal fluid geochemistry change and 0-5% hydrogen gas decrease.

Conclusions:

• Underground hydrogen storage in methane reservoirs presents complex biogeochemical interactions.
• Initial experiments indicate minimal hydrogen loss and geochemical alteration in the short term.
• Further research is crucial to fully understand and mitigate potential impacts of hydrogen storage.