水流动强化天然气水合物降压分解研究

The Study on Natural Gas Hydrate Depressurization Dissociation Strengthened by Water Flow Process

降压法被认为是最经济可行的天然气水合物开采方法,但开采后期驱动力不足、甚至产生水合物的二次生成,因此其应用受到限制。本文将降压法与水流动结合提升水合物分解驱动力,研究不同降压模式和水流动对天然气水合物分解特性的影响。发现当降压结合水流动时,压降为水合物分解提供初始驱动力,且压降越大水合物分解驱动力越大。同时水流动能够加快传热传质过程,为水合物分解提供额外的驱动力。在快速降压结合水流动模式中,较高背压下水流动为水合物分解提供主要的驱动力;在梯度降压结合水流动模式中,降压和水流动共同为水合物提供分解驱动力,对水合物分解的促进作用更加显著。

Depressurization is regarded as the most economic and feasible method of natural gas hydrate exploitation,however,its application is limited by the insufficient driving force in late stage of exploitation process and the hydrate re-formation.In order to enhance the hydrate dissociation driving force,depressurization combined with water flow was used to dissociate natural gas hydrate in this study,and further investigate the influence of water flow process and different depressurization modes on hydrate dissociation characteristics.The results showed that when depressurization combined with water flow,depressurization can supply the initial driving force for hydrate dissociation,and the driving force increased with the pressure drop increase.Meanwhile,water flow accelerated the mass and heat transfer process and provided the extra hydrate dissociation driving force.What’s more,water flow process supplied the main driving force for dissociating hydrate under a higher backpressure in the mode of combination rapid depressurization with water flow.Depressurization and water flow supplied the driving force to dissociate hydrate in the mode of combination gradient depressurization with water flow,there has an obvious promoting effect on hydrate dissociation.