Abstract: Hydrate deposition is a main reason for the plugging in oil and gas transmission pipelines. This paper investigates the common experimental apparatus used for hydrate deposition research,including micromechanical force apparatus,rocking cells and flow loops of different scales. According to the researches performed using the apparatuses above and through computational fluid dynamics simulations,hydrate particle bedding,hydrate film growth and hydrate particle wall adhesion are identified to be the three mechanisms of hydrate deposition. High hydrate concentration,large hydrate particle size and low fluid velocity together lead to hydrate particle bedding. When there is a temperature gradient between the pipe wall and the bulk phase,gas molecules or water molecules tend to diffuse to the cooler pipe wall to form film growth deposition. The capillary liquid bridge force and the van der Waals force between hydrate particle and the pipe wall could count for adhesion deposition. For the three deposition mechanisms,deposition characteristics and deposition models were introduced respectively. Hydrate deposition mechanisms are closely related to subcooling and they can besegregated depending on the fluid subcooling degree at different pipeline positions. The optimization of deposition model and the coupling between hydrate deposition characteristics and flow characteristics have a great significance for oil-gas flow assurance,and is the main focus of the future research.

Key words: hydrate, deposition, bedding, film growth, adhesion

摘要： 水合物在油气输送管线内的沉积是导致管线堵塞的重要原因。本文调研了国内外水合物沉积研究常用的实验装置，主要包括微机械力测量装置、摇晃式反应釜和不同规模的实验环路。利用上述装置的实验研究及相关计算流体力学模拟研究共同表明，水合物颗粒的管线着床、水合物的管壁膜生长和水合物颗粒的管壁黏附是油气输送管线内水合物沉积的3种主要机理。水合物浓度过高、水合物颗粒粒径过大及管内流速过低是水合物颗粒着床沉积的主要原因。管壁和流体间存在温度梯度且管壁处过冷度较大时，水分子或气体分子由流体内部向管壁处的扩散是引发水合物膜生长沉积的根本原因。水合物颗粒与管壁间的毛细液桥力和范德华力是粘附沉积产生的主要原因。针对3类沉积机理，分别介绍了其沉积特性及相关沉积模型。过冷度与水合物的沉积机理密切相关，因此可根据流体过冷度的大小对管线不同位置处的水合物沉积机理进行区分。沉积模型的完善及水合物沉积特性与流体流动特性间的耦合对油气流动安全保障具有非常重大的意义，是未来研究的重点。

关键词: 水合物, 沉积, 着床, 膜生长, 粘附