Author Identifier

Masoud Aslannezhad: https://orcid.org/0000-0002-7113-7341

Date of Award

2026

Keywords

Hydrogen geo-storage, CO2 sequestration, digital core analysis, pore network modeling, upscaling, reservoir simulation, micro-CT

Document Type

Thesis

Publisher

Edith Cowan University

Degree Name

Doctor of Philosophy

School

School of Engineering

First Supervisor

Alireza Keshavarz

Second Supervisor

Stefan Iglauer

Third Supervisor

Zhenjiang You

Abstract

This thesis investigates how hydrogen (H2) and carbon dioxide (CO2) behave when stored deep underground, attempting two urgent challenges in the shift to clean energy: 1) creating safe underground hydrogen storage (UHS) and 2) achieving secure, long-term CO2 sequestration. Both gases behave in complex ways when they encounter rocks and underground water, so this research brings together studies on fluid behaviour, advanced rock imaging, and computer simulations to build a complete understanding of underground storage.

The first part of the thesis focuses on hydrogen, which is seen as a clean fuel for the future. While hydrogen has great potential, storing it on the surface is risky because it is highly flammable, leaks easily, and is difficult to handle safely. Underground storage is a promising alternative, but many factors affect how well hydrogen can be stored in rock formations. This research reviews how key factors, such as salinity, temperature, pressure, rock surface roughness, and the presence of organic material, impact wettability, which is a critical property that controls how hydrogen moves through and stays trapped in underground reservoirs. It also compares underground hydrogen storage to natural gas and CO2 storage, helping to identify challenges and best practices for future hydrogen storage projects.

The next part of the thesis addresses a key problem: although hydrogen can be produced on a large-scale using steam methane reforming (SMR), this process produces large amounts of CO2. To solve both the hydrogen storage and CO2 emission problems together, a new method is proposed: using coalbed methane (CBM) reservoirs to both separate hydrogen from CO2 and store the CO2 underground at the same time. This idea is tested using advanced simulation models that consider multiple processes—like how gases flow and stick to the coal, how the coal swells or shrinks, and how gases diffuse inside. The results are promising, showing that it’s possible to separate more than 80% of the hydrogen while safely storing over 90% of the CO2 at the same time, offering an efficient and innovative solution.

The thesis then focuses on improving how we understand and model underground storage sites by using digital core analysis (DCA) and high-resolution micro-CT imaging. These tools allow us to look inside rocks at the microscopic level, revealing the tiny pores where gases like CO2 and hydrogen flow and get trapped. However, while these tools provide detail, their data is very small-scale and must be scaled up to be useful for larger reservoir models. To solve this problem, the research develops new upscaling methods that allow pore-scale data to be included in full-size reservoir simulations.

As a real-world case study, the thesis applies these methods to the Otway Formation in Australia, a well-known site for CO2 storage research. The study shows how rock features like layering, facies, wettability, and capillary trapping affect how gases move and stay trapped underground. It also builds pore-scale models to study how gases displace water (drainage) and how water re-enters the pores (imbibition), producing important curves that describe how much gas is trapped and how easily it can flow. These findings are essential for improving predictions of gas movement and storage capacity in real reservoirs. By bringing together fluid behaviour research, new storage concepts, advanced rock imaging, and multi-scale modelling, this thesis creates a strong foundation for improving the safety, efficiency, and reliability of underground hydrogen and CO2 storage. The results provide practical tools and knowledge to help design better underground storage projects, supporting global efforts to reduce greenhouse gas emissions and move toward a cleaner, more sustainable energy future.

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Access to this thesis is embargoed until 25th April 2027 

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Link to publisher version (DOI)

10.25958/17tb-q108