Method and apparatus to monitor reformation and replacement of CO2/CH4 gas hydrates

A method for monitoring production from a methane hydrate reservoir includes obtaining a plurality of temperature measurements in a wellbore connected with the methane hydrate reservoir; and deriving a parameter relating to conversion of methane hydrate to carbon dioxide (CO2) hydrate by injection of liquid CO2, wherein the deriving uses a modeling program and the plurality of temperature measurements, wherein the modeling program uses at least one parameter relating to a thermodynamic properties that are substantially different between methane and CO2. The at least one parameter relating to thermodynamic properties may include Joule-Thomson coefficients of methane and CO2. The parameter relating to the conversion of methane hydrate to CO2 hydrate may include a ratio of methane and CO2 in a mixed fluid.