天然气水合物钻采技术

Technology of natural gas hydrate drilling and recovery

天然气水合物是一种在特定的低温高压条件下由水和天然气形成的冰态物，其钻采技术要求高、难度大。总结了目前国内外天然气水合物钻井关键技术。包括钻井液冷却技术、特殊钻具工艺以及关井、洗井、固井等技术。开采技术是实现天然气水合物开发的关键，从细分天然气水合物藏的赋存状态、成藏模式和聚集类型出发，介绍了加热法、降压法、注温水一降压法、CO2置换法、高压射流法等开采方法，对比了各种开采方法的优缺点，可根据不同条件天然气水合物藏优选开采方法。该研究对开发冻土地区及海洋天然气水合物具有参考价值。

Natural gas hydrate is a kind of ice-state materials that is formed by water and natural gas under specific low temperature and high pressure conditions. The technology requirements of drilling and recovery of the natural gas hydrate are high and difficult. This paper summarizes the key teehnologies of natural gas hydrate drilling at home and abroad, including drilling fluid cooling technology, special drilling tool technology and well drilling, washing and cementing techniques. The mining technology is the key to realize the development of natural gas hydrate. The recovery methods of heating, depressurization, warm water injection - depressurization, CO2- substitution, anti high-pressure jet are introduced, proceeding from the partitioning of the oceurrence, SRCA modes and accumulation types of gas-hydrate reservoirs. The advantages and disadvantages of various mining method are compared. The mining methods can be optimized according to the gas-hydrate in different conditions. This study has reference value for the development of permafrost and offshore or marine gas hydrate.