Publications

To achieve Net Zero Emission 2060, Indonesia is actively planning CCS/CCUS programs in its oil and gas fields. Among many subsurface parameters considered for those programs, the seal is one of the most critical parameters to ensure the stored CO2 will not leak and cause environmental problems. The widely used method for measuring seal capacity is Mercury Injection Capillary Pressure (MICP) on shale rock as the seal of the reservoir/saline aquifer to be injected. Problems arise due to the core scarcity from shale intervals acting as a top or intra-formational seal. Our results corroborate several previous studies that drill cuttings can be used to analyze seal capacity. The MICP results of the solid core compared to simulated drill cuttings show similar porosity and lie within a similar trend compared to published data from the USA and Australia. To obtain reliable samples, the drill cuttings should be treated by performing rigorous procedures to separate in situ cutting from the ones that fell from above, followed by MICP test with a proper closure correction. However, our MICP results of solid core, simulated cutting, and actual drill cuttings show lower entry and threshold pressure than most values in the literature. These results raise questions about the seal capacity of Indonesian shale and its applicability for CCS/CCUS storage. Even so, Indonesian shales have been proven to seal many reservoirs, as shown by Indonesia's active oil and gas fields. The study presented here depicts the mild effects of clay contents and the prominent effects of porosity, affected by compaction and mechanical maturity, on the entry pressure. Additionally, how the pore throat size distribution controls the threshold pressure and the sensitivity of contact angle in determining seal capacity or the maximum CO2 column height. Lastly, the potential seal corrosion in the studied field and recommendations for further study on the laboratory analysis of reactive (chemical) transport and their simulation.