Indexed by:会议论文

Date of Publication:2019-01-01

Included Journals:CPCI-S、EI

Volume:158

Page Number:5390-5395

Key Words:Methane hydrate; depressurization; Joule-Thomoson effect;wellbore

Abstract:Methane hydrate has great value of exploitation as a kind of clean energy, many countries have carried out exploitation test before. It was confirmed in previous research that using depressurization is the most stable and efficient method to exploit methane hydrate in lots of exploitation ways. Since the wellbore head is close to pressure fluctuation region in the process of methane hydrate dissociation, it causes the Joule-Thomson effect. This phenomenon may lead to the temperature decline in the wellbore head, and may hinder the methane hydrate dissociation. The characters of gas-liquid transfer in the process of hydrate dissociation near wellbore was studied. The efficiency of gas production was also evaluated. The result shows that the hydrate reservoir close to the vessel wall dissociated quickly because of the enough dissociation latent heat. And the drastic gas-liquid flow causing the Joule-Thomson effect in both sides of the wellbore with a huge temperature decline. Comparing with different dissociation back pressures in the experiments, the lower back pressure will increase the amount of gas production. But the lower back pressure will lead to a huge temperature decline in wellbore head and cause the ice blockage. (C) 2019 The Authors. Published by Elsevier Ltd.