Selection and Maturation of a CO2 Store for Oman's First Blue Hydrogen Project

In May 2022, a Memorandum of Understanding was signed between Petroleum Development Oman (PDO) and Shell to pursue the development of Oman's first Blue Hydrogen project with Carbon Capture Utilisation and Storage (CCUS), based at the Port of Duqm. To create a certified blue product, the CO2 associated with hydrogen production from natural gas must be permanently sequestered underground. This required selection and maturation of a suitable CO2 storage site in the onshore area of Oman with sufficient capacity for the project, sustained reservoir injectivity, robust containment and adequate monitorability using available technologies. The subsurface of Oman contains a vast succession of geological reservoirs and seals, from Pre-Cambrian through to the Tertiary, many of which are proven petroleum systems. It was quickly determined that saline aquifers, rather than depleted gas fields, presented the best opportunity for CO2 storage, due to their size and separation from Oman's dense network of hydrocarbon-producing fields and infrastructure. PDO's Block 6 concession contains the most likely candidates from a geological perspective, as it covers the main sedimentary basins within the country, plus benefits from a rich subsurface dataset for evaluation of the CO2 store. This paper describes the process of selection and subsurface characterisation of a suitable saline aquifer CO2 store in Central Oman, to meet the pore space requirements of CO2 sequestration for the lifetime of the proposed Blue Hydrogen project.