Current status and prospects on natural gas hydrate exploitation methods

Abstract:

Natural gas hydrate is a type of solid clean energy with huge reserve， which is therefore considered as a substitute for traditional fossil fuels and have attracted much attention around the world. Due to its occurrence in low-temperature and high-pressure marine and permafrost environments， the key to achieving commercial exploitation is to find out economical and efficient exploitation methods. Based on the current research status of laboratory research， numerical simulation， and on-site experiments， the exploitation effects of methods such as depressurization， heat injection， chemical inhibitor injection， CO₂ displacement and combination method were analyzed， and the advantages and limitations of each method were discussed. The existing exploitation methods are mainly limited by low reservoir permeability and poor thermal conductivity， and have not been able to achieve long-term continuous gas production. To address the above issues， the in-situ resistance heating method for reservoirs is proposed to improve thermal utilization efficiency， and it is believed that hydraulic fracturing and permeability enhancement technology is an effective measure to increase reservoir permeability and assist in efficient gas production through production methods such as depressurization； Regarding the potential instability of reservoirs caused by hydrate exploitation， it is believed that the use of CO₂ replacement method can strengthen the reservoir， and the use of supercritical CO₂ injection technology can improve the CO₂ replacement rate.

Key words:natural gas hydrate;exploitation method;depressurization method;in-situ heating method;combination method;reservoir permeability enhancement