Caprock integrity and sealing capacity during underground hydrogen storage

R&D Focus Area:
Underground storage

Lead Organisation:
Curtin University

Funding:
Future Energy Exports CRC (PhD Project)

Status:
Active

Start date:
February 2024

Completion Date:
November 2027

Project summary description:
Underground hydrogen storage in depleted gas reservoirs offers the dual benefits of

• Repurposing existing geological structures and surface facilities, and
• Advancing sustainable energy storage in the range of tens to hundreds of TWh.

Caprocks play a crucial role in maintaining the structural integrity of these geological structures by acting as barriers to gas (methane) migration upwards. While in these depleted gas reservoirs, caprock seals to methane, little research work has been conducted to ensure whether the same caprock can seal to hydrogen with fast cyclic loading during the underground hydrogen storage. This knowledge gap triggers uncertainties and perceived risks in underground hydrogen storage technology development.

This research project aims to address the knowledge gap through a combination of experiment, analytical and numerical modelling.

• First, hydrogen conditioned caprock wetting characteristics will be measured at reservoir condition of pressure and temperature. Together, a physical model will be development to predict the wetting behaviour of the hydrogen-conditioned caprock.
• Second, hydrogen-conditioned caprock mechanics will be tested through triaxial rock mechanical experiments. A few triplets’ caprocks will be extracted from Western Victoria and Perth basins which will be subjected to aging in brine at reservoir pressure and temperature over 300 degrees C to accelerate the geochemical and physiochemical process equivalent to lifetime of underground hydrogen storage systems. Afterwards, static, and dynamic moduli of the caprock will be tested through triaxial rock mechanical experiments. Axial and radial deformations of the samples during stress cycling will be measured using local linear variable differential transformers together with acoustic velocity measurements.
• Third, micro-seismicity together with triaxial rock mechanical tests will be deployed to investigate hydrogen-conditioned micro-fracture mechanics through fracturing and reactivation processes.

Further information:
https://www.fenex.org.au/connect/

 

September 2024