A computer-implemented method for predicting a volume of biogenic gas for an area of interest, the method comprising: (a) identifying a plurality of environmental characteristics for one or more periods of time for the area of interest, wherein the plurality of environmental characteristics comprise at least a hydrogen concentration and a carbon dioxide concentration; (b) determining a methanogenesis rate for the one or more periods of time for the area of interest using the following equation: Rate = k * M * D * A * R e wherein k is a rate constant; wherein M is a biomass; wherein D is a function indicating the hydrogen activity for the period of time in the area of interest, determined by the equation: D = H 2 K D + H 2 where H 2 is the concentration of H 2; and where K D is the H 2 concentration at which the specific growth rate of the microbial community or organism is one-half of its maximum, wherein A is a function indicating the carbon dioxide activity for the period of time in the area of interest, determined by the equation, A = CO 2 K A + CO 2 where CO 2 is the concentration of CO 2; and where K A is the CO 2 concentration at which the specific growth rate of the microbial community or organism is one-half of its maximum; and wherein R e is a thermodynamic function indicating the microbial respiration energy (R e) for the period of time in the area of interest determined by the equation where Δ G redox - m Δ G atp is the free energy change of microbial respiration; where m is the number of adenosine triphosphates (ATPs) synthesized; where X is the average stoichiometric number of reaction; where R is the universal gas constant; and where T is the temperature; and (c) predicting the volume of the biogenic gas based on the methanogenesis rate for the one or more of the periods of time for the area of interest. (a) identifying a plurality of environmental characteristics for one or more periods of time for the area of interest, wherein the plurality of environmental characteristics comprise at least a hydrogen concentration and a carbon dioxide concentration; (b) determining a methanogenesis rate for the one or more periods of time for the area of interest using the following equation: Rate = k * M * D * A * R e wherein k is a rate constant; wherein M is a biomass; wherein D is a function indicating the hydrogen activity for the period of time in the area of interest, determined by the equation: D = H 2 K D + H 2 where H 2 is the concentration of H 2; and where K D is the H 2 concentration at which the specific growth rate of the microbial community or organism is one-half of its maximum, wherein A is a function indicating the carbon dioxide activity for the period of time in the area of interest, determined by the equation, A = CO 2 K A + CO 2 where CO 2 is the concentration of CO 2; and where K A is the CO 2 concentration at which the specific growth rate of the microbial community or organism is one-half of its maximum; and wherein R e is a thermodynamic function indicating the microbial respiration energy (R e) for the period of time in the area of interest determined by the equation where Δ G redox - m Δ G atp is the free energy change of microbial respiration; where m is the number of adenosine triphosphates (ATPs) synthesized; where X is the average stoichiometric number of reaction; where R is the universal gas constant; and where T is the temperature; and wherein k is a rate constant; wherein M is a biomass; wherein D is a function indicating the hydrogen activity for the period of time in the area of interest, determined by the equation: D = H 2 K D + H 2 where H 2 is the concentration of H 2; and where K D is the H 2 concentration at which the specific growth rate of the microbial community or organism is one-half of its maximum, wherein A is a function indicating the carbon dioxide activity for the period of time in the area of interest, determined by the equation, A = CO 2 K A + CO 2 where CO 2 is the concentration of CO 2; and where K A is the CO 2 concentration at which the specific growth rate of the microbial community or organism is one-half of its maximum; and wherein R e is a thermodynamic function indicating the microbial respiration energy (R e) for the period of time in the area of interest determined by the equation where Δ G redox - m Δ G atp is the free energy change of microbial respiration; where m is the number of adenosine triphosphates (ATPs) synthesized; where X is the average stoichiometric number of reaction; where R is the universal gas constant; and where T is the temperature; and (c) predicting the volume of the biogenic gas based on the methanogenesis rate for the one or more of the periods of time for the area of interest.