Harnessing shale for net-zero: economic and environmental impact of CO$$_2$$ sequestration in the Marcellus shale formation

CO $$_2$$ sequestration in subsurface shale formations is a promising strategy for reducing atmospheric carbon emissions. This study evaluates the potential of CO $$_2$$ storage in a shale-gas well from the Marcellus shale formation using a numerical compositional reservoir model developed with the stimulated reservoir volume (SRV) approach. The model was history-matched by adjusting key SRV parameters, including permeability, porosity, and fracture spacing. After reservoir depletion, CO $$_2$$ was injected until the original reservoir pressure was restored. The net present value (NPV) was estimated considering gas sales, production, injection costs, and capital expenses, while the environmental impact was assessed by calculating the net carbon footprint, incorporating both carbon emissions and sequestered CO $$_2$$ volume. A Monte Carlo simulation with 1000 scenarios addressed uncertainties in SRV characteristics, providing probabilistic distributions for NPV, carbon footprint, storage volume, and sequestration duration. Results demonstrate that CO $$_2$$ sequestration through a shale gas well can achieve economic feasibility with favorable gas prices and cost efficiency. Notably, over 88% of lifecycle carbon emissions can be sequestered into the reservoir, aligning with net-zero objectives. This study offers a comprehensive framework integrating economic and environmental analyses, emphasizing the critical role of SRV characteristics in both gas production and CO $$_2$$ storage efficiency. By combining numerical simulation, lifecycle assessments, and probabilistic analysis, this work highlights the significant potential of unconventional reservoirs in advancing global decarbonization goals.