Effect of thermal stimulation on gas production from hydrate deposits in Shenhu area of the South China Sea  

作　　者：SU Zheng HUANG Li WU NengYou YANG ShengXiong 

机构地区：[1]Key Laboratory of Renewable Energy and Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences [2]Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences [3]Guangzhou Marine Geological Survey

出　　处：《Science China Earth Sciences》2013年第4期601-610,共10页中国科学（地球科学英文版）

基　　金：supported by the China Geological Survey and Lawrence Berkeley National Laboratory, the National Natural Science Foundation of China (Grant No. 41076037);China Geological Survey (Grant No.GZH2012006003);National Basic Research Program of China (Grant No. 2009CB219508)

摘　　要：The Shenhu area on the northern continental slope of the South China Sea （SCS） is one of the promising fields for gas hydrate exploitation. The hydrate-bearing layer at drilling site SH2 is overlain and underlain by permeable zones of mobile water. In this study a vertical well was configured with a perforated Interval I for producing gas and a coiled Interval II for heating sed- iment, The hydrate is dissociated by a small depressurization at Interval Ⅰ and a thermal stimulation at Interval Ⅱ. The numeri- cal simulations indicate that the thermal stimulation has a significant effect on gas release from the hydrates in the production duration and improves the gas production in the late period. The gas released by thermal stimulation cannot be produced as quickly as the production gets operated because of the hard pathway for fluids to flow in the sediments. The gas production is enhanced due to the heating for 7242 m3 in the whole production. Increasing heating temperature at Interval Ⅱcan improve gas production and restrain water output, and advance the arrival time of the gas flow from the zone at Interval Ⅱ. The absolute criterion and relative criterion suggest that the thermal stimulation in the production schemes is pronounced for releasing gas from the hydrate deposit, but the production efficiency of gas is limited by the sediment of low permeability. The study pro- vides an insight into the production potential of the hydrate accumulations by thermal stimulation with depressurization in two wells, and a basis for analyzing economic feasibility of gas production from the area.The Shenhu area on the northern continental slope of the South China Sea (SCS) is one of the promising fields for gas hydrate exploitation. The hydrate-bearing layer at drilling site SH2 is overlain and underlain by permeable zones of mobile water. In this study a vertical well was configured with a perforated Interval I for producing gas and a coiled Interval II for heating sediment. The hydrate is dissociated by a small depressurization at Interval I and a thermal stimulation at Interval II. The numerical simulations indicate that the thermal stimulation has a significant effect on gas release from the hydrates in the production duration and improves the gas production in the late period. The gas released by thermal stimulation cannot be produced as quickly as the production gets operated because of the hard pathway for fluids to flow in the sediments. The gas production is enhanced due to the heating for 7242 m 3 in the whole production. Increasing heating temperature at Interval II can improve gas production and restrain water output, and advance the arrival time of the gas flow from the zone at Interval II. The absolute criterion and relative criterion suggest that the thermal stimulation in the production schemes is pronounced for releasing gas from the hydrate deposit, but the production efficiency of gas is limited by the sediment of low permeability. The study provides an insight into the production potential of the hydrate accumulations by thermal stimulation with depressurization in two wells, and a basis for analyzing economic feasibility of gas production from the area.

关 键 词：gas hydrates Shenhu area hydrate dissociation thermal stimulation numerical simulation 

分 类 号：P744.4[天文地球—海洋科学]