天然气水合物开采方法研究进展

Advances in natural gas hydrate recovery methods

天然气水合物(简称水合物)是天然气(主要成分甲烷)和水在高压和低温条件下形成的类冰固体化合物.我国在南海北部陆坡和祁连山冻土带的钻探取样结果证实了其潜在储量,国家将水合物开采研究归入战略发展规划.本文首先简要介绍国际水合物地层成藏和分类的研究现状、现有水合物开采方法与原理;然后重点总结Messoyakha,Mallik和Alaska现场分别采用降压、注热与降压联合和CO_2置换与降压联合的试验性开采的研究进展以及试验性开采过程中物理、化学监测手段的应用情况;最后结合我国水合物地层特点提出类似采矿的机械—热开采水合物方法,重点介绍了其中的工艺流程和基本科学原理,为实现我国水合物高效、安全、经济的开采方案的制定提供参考.

Natural gas hydrate is an ice-like solid compound composed of mainly methane molecules and water molecules under high temperature and low temperature. Drilling and sampling in the slope of the northern South China Sea and permafrost of the Qilian Mountain have confirmed the potentially huge hydrate reserves, and the hydrate recovery is being studied as a strategic energy resource. First, brief overview on the hydrate formation and existing hydrate recovery methods containing the engineering principles were given. Second, test productions i.e. depressurization, combination of thermal method and depressurization, combination of depressurization and carbon dioxide replacement in Messoyakha, Mallik and Alaska zone were summarized, respectively. And the applications of real-time monitoring by physical and chemical technologies were provided. Finally, a new concept similar to mining i.e. mechanical-thermal hydrate recovery method was presented based on the geological-mechanical characteristics in China and the technological process and scientific principles were introduced and overviewed.