ENHANCED METHANE HYDRATE RECOVERY USING EXOTHERMIC HEAT OF CO₂ HYDRATE -EXPERIMENTAL RESULTS OF HEATING AND PERMEATION PHENOMENA IN SUPERCOOLING CONDITION-

Abstract

 Methane hydrate (MH) in Nankai-trough is expected as a Japanese domestic future energy resource of natural gases. It is mainly condensed in the pores of unconsolidated oceanic sedimentary layers. CO₂ hydrate that formed from CO₂ and water shows functions of exothermic heat and phase equilibrium in the same environment under the sea bottom. The functions of CO₂ hydrate could be used for enhanced recovery of methane hydrate. We had shown experimental validations that warming ability of the layer sediments by using exothermic heat of CO₂ hydrate and CO₂ injection method using the phase equilibrium of CO₂ hydrate. In this paper, we show experimental validation about the phenomena about the exothermic heat of CO₂ hydrate formation and CO₂ permeation when CO₂ is injected into super cooling layer sediments, which temperature is lower than phase equilibrium temperature by few degrees Celsius. We think that this validation made higher adaptability of CO₂ for enhanced recovery of methane hydrate.