天然气水合物快速分解实验研究

Experimental Research on Fast Decomposition of Natural Gas Hydrate

针对天然气水合物堵塞油气管道以及海洋天然气水合物的开发的问题,如何快速将水合物分解对于天然气安全运输和水合物的开发有着重要意义。采用了降压和注化学剂的方法对天然气水合物在静态以及动态的分解动力学参数进行了研究。结果表明:水合物的分解经历了初始加速、主力生产以及产量衰竭3个阶段,初始加速期极短,占整个分解时间的比例甚至不到5%;分解推动力越大,水合物的峰值分解速率就越快,例如在静态条件下,水合物在1.18 MPa的分解推动力下的峰值分解速率为1 316.4 mL·min^(-1),而在3.18 MPa的推动力下,水合物的分解速率达到了4 407.05 mL·min^(-1);在分解推动力以及注入乙二醇的体积分数相同的情况下,水合物在动态条件下的峰值分解速率要比静态条件下的快;水合物在静态条件以及动态条件下通过联合1.18 MPa分解推动力和注20%乙二醇的方法,相较于单独在1.18 MPa的分解推动力作用下,峰值分解速率分别提高了2.5倍和2.8倍。研究成果为现场解决水合物堵塞天然气管线的问题以及海洋天然气水合物的开发提供重要的理论指导和一定的数据支持。

In view of the problems of gas hydrates blocking oil and gas pipelines and the development of marine gas hydrates,how to quickly decompose hydrates is of great significance for the safe transportation of natural gas and the development of hydrates.In this article,the methods of pressure reduction and chemical injection were used to study the static and dynamic decomposition kinetic parameters of natural gas hydrate.The results show that,the decomposition of hydrate has gone through three stages:initial acceleration,main production and output depletion.The initial acceleration period is extremely short,accounting for less than 5%of the total decomposition time;The greater the driving force of decomposition,the faster the peak decomposition rate of hydrates.For example,under static conditions,the peak decomposition rate of the hydrate decomposition driving force at 1.18 MPa is1 316.4 mL·min^(-1),while the driving force at 3.18 MPa,the decomposition rate of hydrate is 4 407.05 mL·min^(-1);When the decomposition driving force and the volume fraction of injected ethylene glycol are the same,the peak decomposition rate of hydrate under dynamic conditions is faster than that under static conditions;The method of combining 1.18 MPa decomposition driving force and 20%ethylene glycol injection under static and dynamic conditions of hydrate,compared with the decomposition driving force of 1.18MPa alone,the peak decomposition rate is increased respectively by 2.5 times and 2.8 times.The research results provide important theoretical guidance and certain data support for solving the problem of hydrates blocking natural gas pipelines and the development of marine gas hydrates.