Modelling the uncertainty and risks associated with the design and life cycle of CO₂ storage in coalbed reservoirs

The main objective of the research reported in this paper was to address the uncertainties associated with coal seam reservoir performance during and after CO₂ injection in order to establish a methodology for the design, prediction and risk evaluation of safe and environmentally sound CO₂ storage in coal seam reservoirs. Full field scale simulations up to 1,000 years with over 140 permeability realisations and various swelling coefficients and sorption isotherms have shown that controlling the injection well bottomhole pressure ensures no overpressuring of the coalbeds or the caprock. Long-term leakage simulations with high cement deterioration and CO₂ leakage rates have shown that the likelihood of a leakage of 1% of the total volume of CO₂ stored over 1,000 years is low, and can be mitigated against through careful operational planning and reservoir management during CO₂-ECBM and CO₂ storage.