CO ₂ sequestration potential in Depleted Hydrocarbon fields - A geochemical approach

Area of Science:

• Geological storage of carbon dioxide
• Energy transition technologies
• Reservoir engineering

Background:

• Carbon dioxide (CO2) emissions reduction is vital for the energy transition.
• Depleted hydrocarbon fields (DHF) offer cost-effective CO2 storage solutions due to existing infrastructure and knowledge.
• Interactions between injected CO2 and reservoir fluids pose a significant challenge for CO2 storage in DHFs.

Purpose of the Study:

• Investigate the potential of DHFs for CO2 storage.
• Examine CO2 interactions with carbonate-siliciclastic reservoirs.
• Assess long-term CO2 sequestration mechanisms and potential risks.

Main Methods:

• Utilized PHREEQC software to simulate CO2 interactions with reservoir rock, water, and methane.
• Employed CMG-GEM software for long-term CO2 sequestration analysis, including dissolution and residual trapping.
• Modeled CO2 behavior under various concentration scenarios in a Marismas field analogue.

Main Results:

• CO2 injection formed carbonic acid, leading to mineral dissolution and precipitation of siderite and clay minerals.
• Siderite's colloidal nature and Ca-montmorillonite swelling can cause pore throat clogging, potentially reducing reservoir permeability.
• CMG-GEM simulations confirmed CO2 plume establishment and validated the sequestration process.

Conclusions:

• DHFs are viable for CO2 storage within the CEEGS technology framework.
• Potential risks from mineral precipitation can be managed through anthropogenic control of reservoir parameters.
• The study highlights the importance of understanding geochemical interactions for safe and effective CO2 sequestration.