Indexed by:会议论文

Date of Publication:2019-01-01

Included Journals:CPCI-S、EI

Volume:158

Page Number:5213-5218

Key Words:Oceanic methane hydrate; Vertical well; Aggressive depressurization; Permeability improvement; Enhanced gas recovery

Abstract:The 2013 and 2017 offshore methane hydrate production tests conducted in the Nankai Through, Japan, showed the technical feasibility of the oceanic methane hydrate production by depressurization. However, the gas production rate was still far from the economical utilization level. Therefore, this study focused on the enhanced gas recovery from the methane hydrate reservoir in the Nankai Through using a vertical well by depressurization. A geological model simulating the real oceanic methane hydrate reservoir was built first, and numerical simulations of gas production using two special production strategies (i.e., the aggressive depressurization and permeability improvement) were carried out for a period of 5 years to verify the enhanced effects on the gas recovery. Based on the simulation results, it was found that the middle low-permeability silt-dominated layers played an important part in the processes of the hydrate dissociation and gas production from the methane hydrate reservoir in the Nankai Through. The aggressive depressurization only had a limited effect on the increase in gas production, while the method of the permeability improvement was more efficient for the enhanced gas recovery than the aggressive depressurization. In the future field test, if these two methods can be combined, the gas recovery is expected to be further enhanced. (C) 2019 The Authors. Published by Elsevier Ltd.