Abstract

In this paper we analyze the production of methane gas from methane hydrate deposits when heat is supplied by an electrical heater located in the reservoir. The reservoir is assumed to have cylindrical symmetry of variable external radius and variable thickness. By means of the enthalpy method we determine numerically the transient response of this system under a constant applied electrical power supplied to a cylindrical heater located at the center of the reservoir and at different depths. We determine the volume of methane hydrate that will melt and the energy equivalent of the gas thus produced. The energy efficiency of the heating process is obtained as the ratio of the gas equivalent energy to the applied energy.

In the calculations the heater temperature is maintained constant by a down-hole controller, so as to avoid the conversion into steam of the water produced. For different levels of applied electrical power, at a given heater temperature, we find that there is an optimal value of heater length where the ratio of the equivalent energy produced to the energy input is a maximum.

The energy efficiency of this heating process is the critical factor in determining the feasibility of an electrical heating production scheme.

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