Abstract: A method for the evaluation, design and optimization of in-situ bioconversion processes for the conversion of carbon to methane and other useful gases and liquids. The method utilizes a comprehensive computer simulation model for accurately simulating the physical and dynamic conditions in a subterranean carbon-bearing formation and the effects of stimulating the growth of indigenous or non-indigenous microbes therein for the bioconverstion of carbon to methane and other useful gases and liquids. The method enables the prediction of bioconversion rates and efficiencies under a range of variables, and thus provides for the optimization of in-situ bioconversion process design and operation.