Developing Large-Scale Saline Aquifer as a CO2 Storage Hub Offshore Malaysia
Authors: Tiwari P. K. , Das D. , Chidambaram P. , Ebining Amir M. B , Abu Bakar M. B. , Tewari R. D. , Kechut N. I. 
Published: February 2025

The rising CO2 emissions resulting from the development of high CO2 contaminated gas fields in Malaysia necessitate the identification of appropriate, secure, and capacious reservoirs for CO2 storage. Large-scale saline aquifers have emerged as promising solutions for establishing a storage hub equipped with extensive onshore injection facilities. Nevertheless, the development of a large-scale saline aquifer as a CO2 storage hub offshore Malaysia presents numerous substantial challenges. The current study focusses on identifying and evaluating the associated risks and uncertainties and formulating a mitigation strategy for the development of a large-scale storage hub within synrift sediments of a rift graben off the coast of peninsular Malaysia (PM).

When establishing a large-scale CO2 storage hub, it's crucial to prioritize two key elements: containment integrity and storage capacity. However, these components carry inherent risks that demand careful management throughout the storage development process. Containment integrity entails risks related to reservoir and overburden formations, structural features, and well integrity within the storage reservoirs. Conversely, storage capacity can be influenced by factors like reservoir continuity, aquifer size and strength, caprock strength, and injectivity.

The storage site was analyzed for its containment and capacity through extensive 3D data interpretation for generation of structural maps, mapping of major and minor faults, and attribute extraction, trap & seal analysis, faults & wells integrity analysis, 1D caprock integrity analysis, and effective storage capacity estimation through dynamic simulation. This comprehensive assessment aims to identify potential hazards and risks concerning containment integrity—such as reservoir instability, caprock failure, CO2 migration pathways, and wellbore integrity issues. To facilitate the development of the safe and dependable operation of the offshore CO2 storage site, the likelihood and potential consequences of identified risks are understood, and appropriate risk mitigation measures are planned.

The extensive study of the storage site has leveraged all accessible seismic and log data resulting in the identification of five major risks: Caprock continuity and integrity, Fault Sealing, Structural concerns, Basement Characteristics, and Aquifer Size and Strength. Dynamic simulation results of maximum storage capacity help deciding plausible mitigation plans, such as seismic data acquisition, appraisal well drilling, and coring, have been suggested to tackle these risks. However, quantifying the precise value added by these plans in terms of risk reduction presents a challenge. Additional mitigation strategies, including hybrid seismic inversion, appraisal well drilling, coring, and 3D seismic acquisition, offer potential to reduce uncertainties, with subsequent activities depending on initial phase outcomes. The availability of huge storage capacity with managed pressure and plan for derisking ensure the safety of storage and containment. The workflow for this study to be used as the guideline for any future saline aquifer storage development plan feasibility study.