Indexed by:会议论文

Date of Publication:2019-01-01

Included Journals:CPCI-S、EI

Volume:158

Page Number:5453-5458

Key Words:Hydrate; depressurization; water-saturated sediment; sensible heat; thermal conductivity

Abstract:Natural gas hydrate is a potential source of energy with enormous distribution in permafrost regions and under seafloors. Although quantities of researches have been carried out to investigate the mechanisms of natural gas production from hydrate bearing sediments, few studies have focused on the dissociation behavior in a water-saturated situation, which better mimics the natural conditions. In this work, methane hydrate dissociation was investigated in three kinds of porous media at water-saturated condition, with production pressures of 2.2 MPa, 2.6 MPa, and 3.0 MPa. The results imply that a large quantity of free water remaining in pores increases the sensible heat of the reservoir, largely preventing the occurrence of hydrate reformation and ice generation. The Ste number is introduced to evaluate the impacts of sensible heat and ambient heat transfer. The impact of the thermal conductivity of porous media on ambient heat transfer is weakened due to the existence of residual free water in the pores. The findings could provide some insights into the mechanism of gas production from natural marine sediments through depressurization in terms of heat consumption and transfer. (C) 2019 The Authors. Published by Elsevier Ltd.