Geomechanical modelling of hydrogen injection into a depleted gas field

R&D Focus Areas:
Underground storage

Lead Organisation:
Geoscience Australia

Partners:
CO2CRC, Schlumberger

Status:
Completed

Start date:
February 2022

Completion date:
August 2022

Key contacts:
Lead Investigator: Dr. Eric Tenthorey eric.tenthorey@ga.gov.au

Funding:
The project is funded under the Exploring for the Future program.

Project total cost:
Not applicable

Project summary description:
This Exploring for the Future study will develop geo-mechanical models of hydrogen injection into a depleted gas field, with the aim of understanding key mechanical differences relative to methane or CO₂ injection.

Modelling will be based on previous reservoir models developed for the Otway facility and rock mechanical data that has been collected over the past 20 years. Geo-mechanical modelling will be conducted using industry standard software. The results of the injection modelling will provide information on how the reservoir, caprock and wells may respond mechanically to hydrogen storage. The outputs of the work will not only be relevant to the Otway site, but also more broadly for hydrogen storage, as there have been very few studies conducted on the geomechanics of hydrogen storage.

The geo-mechanical aspects that will be investigated are thermal and pressure changes on stress and fault stability and cap rock integrity, and whether or not fracturing will be initiated at these injection rates at the point of injection. The study will be separated into three distinct phases:

Phase-1: Construction of 1D Mechanical Earth Model (MEM)

At the start of the project, a hypothetical Injection Well (HIW) and depth/ formation where hydrogen injection and storage is to be considered in the Naylor field will be defined. The base case of stresses at the hypothetical well will be obtained and then based on the maximum temperature change that will occur at the HIW due to cooling or heating because of injection, the stress changes will be derived at the wellbore. The impact of the variation of the stress will be translated to downhole flowrates for the various fluids.

Phase-2: Reservoir Dynamic Modelling:

For deriving the stress variations away from the wellbore, a 3D MEM will be constructed. However, to understand the spatial variation of pressure and temperature due to injection, a reservoir dynamic model will be constructed using ECLIPSE. The study will use an existing Petrel Otway static reservoir model developed by CO2CRC.

Phase-3: Construction of 3D MEM:

Based on the Petrel static model, the elastic and rock strength properties will be propagated into the static model. The pre injection stress state of the model will be established. For different injection scenarios, the stress state that is affected due to temperature and pressure will be derived and. fault and caprock integrity evaluated.

Related publications and key links:
Tenthorey, E., Feitz, A., Puspitasari, R., Moh, Hsiao, Suryanto, O., Giddins, M.A., Pallikathekathil, Z., Dandekar, R. 2023. Reservoir modelling and geomechanics of hydrogen storage at the CO2CRC Otway International Test Centre, Schlumberger Digital Forum, 19-22 September 2022, Luzern, Switzerland.

Higher degree studies supported:
Not applicable

 

Reviewed: August 2023