Preliminary Assessment of the Reservoir Rock in the Niger Delta for Carbon Capture and Storage in Depleted Reservoirs

The world is running out of time to be on target for the Paris Agreement to maintain an average global temperature rise of 1.5°C. Carbon capture and storage (CCS) can win the race to anthropogenic gas stabilisation. Characterisation of geological formations is fundamental to ascertain the ability to keep injected carbon in perpetuity without posing a risk to the environment. This study focuses on the characterisation of the mineralogy, petrophysical, petrographic properties and micromorphological data of reservoirs using core samples from the reservoirs in the Niger Delta, Nigeria. A systematic set of specialised equipment such as XRD, X‐ray fluorescence (XRF) and SEM‐EDS was implored to understand the preliminary characterisation of selected reservoirs before carbon dioxide injection. Porosity and permeability were measured using a helium porosimeter to complement the mineralogical composition and morphology. The petrographic and mineralogical characteristics of the core samples provide crucial insights into potential geochemical reactions. Quartz, orthoclase and albite were found to be dominant in all the sampled depo belts with chlorite and garnet being the trace minerals. The sampled depo belts recorded an average porosity of 10% to 30% with permeability averaging 130–300 mD, which surpass the cautionary indicator limits. The findings indicated a positive potential for CCS in the Niger Delta with suitable mineralogical and petrophysical properties. The positive findings of this research pave the way for pilot testing with the physical injection of carbon dioxide. They also set a pathway for enacting and implementing carbon dioxide mitigation guidelines controlling CCS installations by the Nigerian Upstream Petroleum Regulatory Commission (NUPRC).