天然气水合物浆液摩阻的实验研究

随着海洋油气开发向着深海进军,为了防止发生从海底井口到生产平台的多相混输管道天然气水合物堵塞,传统天然气水合物抑制方法将会大大增加开采成本,而以天然气水合物浆液形式进行输送已成为深海油气输送的一种新方法。为此,在天然气水合物壳模型的基础上开发了HyFlow软件,在水—柴油体系的天然气水合物浆液环路实验中,计算了天然气水合物颗粒的粒径,得到了天然气水合物浆液中颗粒大小与含水率的关系,讨论了不同含水率下最大填充系数的确定,分析了颗粒大小对天然气水合物浆液摩阻系数的影响。结果发现:当含水率在15%～25%时,天然气水合物颗粒的表观直径为0.974mm,而摩阻系数约为0.22。此研究结果为模拟计算天然气水合物浆液的流动提供了实验依据,也为正确设计和布置混输管线的工艺流程奠定了基础。

An experimental study on flow friction of natural gas hydrate slurry

As offshore oil and gas recovery is being turned to deep seas, natural gas hydrate blockage has become a big problem in multiphase flow pipelines from wellhead at the sea floor to the offshore platform. Traditional hydrate inhibition methods will add a big burden on the cost of hydrocarbon exploitation in deep seas. Therefore, we adopt a new method of dispersing hydrates into oil phase to form hydrate slurry to transport. In view of this, the HyFlow software is developed based on a shell model of natural gas hydrate. By use of this software, in experiments with hydrate slurry loop in water diesel oil system, we calculate the particle diameter of hydrate crystals, the relationship between which and water cut is thus obtained. Furthermore, we discuss how the maximum filling rate can be determined under different water cut, and what impact the particle size of hydrate has on the friction coefficient of slurry. The results demonstrate that when water cut is 15 ~ 25%, the apparent diameter of hydrate crystals is about 0.974 mm, while the friction coefficient is about 0.22. This experimental study will provide some reference for researchers to predict flow behavior more accurately and to design the layout of pipes and process flow more reasonably in the projects of multiphase transportation pipelines.