TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The monitoring production parameters further include flow rate of the produced gas, chemical composition of the produced gas and at least one of hydrogen or oxygen isotopic composition of produced water. The monitoring of chemical composition of the produced gas involves monitoring amounts of methane, carbon dioxide and hydrogen included in the produced gas. Monitoring of isotopic composition involves monitoring carbon isotopic composition of at least one of methane or carbon dioxide included in the produced gas, monitoring hydrogen isotopic composition of methane or hydrogen included in the produced gas, or an oxygen isotopic composition of carbon dioxide included in the produced gas. Before producing gas from the zone, an increase in reservoir pressure in the zone is monitored, and production of gas from the zone is commenced when the zone's gas saturation reaches a threshold gas saturation based on the reservoir pressure determining the zone's gas saturation. The threshold gas saturation is based on a critical gas saturation of the zone. The threshold gas saturation is 85-95% of the critical gas saturation or 100% of critical gas saturation. Stimulation of microbial conversion of petroleum in the zone to biogenerated methane involves injecting one or more modifiers into the reservoir to stimulate microbial conversion of the petroleum to methane. Fluid containing gas and water is injected into reservoir. At least one of stimulation of the microbial conversion to control the composition of the produced gas or gas saturation in the zone to control mobility of the biogenerated methane is adjusted by adjusting injector well flow rate for injecting at least one of modifier(s) or fluid into the reservoir, a production well flow rate, composition of one or more modifiers injected into the reservoir, amount of one or more modifiers injected into the reservoir, composition of the gas included in the fluid injected into the reservoir, amount of gas included in the fluid injected into the reservoir, amount of water included in the fluid injected into the reservoir, duration of injection, soak and production cycles for the reservoir, or ceasing production of the gas from one or more wells and commencing production of the gas from one or more different wells. Fluid is injected into zone through a set (I) of one or more wells and gas is produced from the zone through other set (II) of one or more wells. Fluid is injected into the zone concurrently with production of gas from the zone. Injection of fluid into the zone is ceased when producing gas from the zone. A soak cycle is allowed to endure in a region of the zone situated proximate a set (III) of one or more wells, when injection and production occur from the set (I,II) of one or more wells. During a later cycle, the set (I) of one or more wells is allowed to endure a soak cycle, fluid is injected into zone through the set (II) of one or more wells and gas is produced from the zone through set (III) of one or more wells. The isotopic and bulk gas composition of the produced gas is predicted using isotope fractionation model when gas production is occurred under optimal conditions. The actual isotopic and bulk gas composition of the produced gas is compared to the predicted isotopic and bulk composition and at least one of stimulation of the microbial conversion to control the composition of the produced gas or gas saturation in the zone to control mobility of the biogenerated methane is adjusted using the comparison.