Abstract The high pressure and low temperature operational conditions of deepwater subsea facilities often result in the formation of gas hydrates, which is one of the most challenging flow assurance issues. The variant water cuts and flowline geometries could result in complicated flow patterns leading to different hydrate formation mechanisms. In previous work, we have developed hydrate formation models both for oil- and water-dominated systems. The model for oil-dominated systems considers the water phase being dispersed as droplets in an oil continuous layer, and uses either a kinetics or a transport model to calculate hydrate formation at the interface of water droplets. On the other hand, water-dominated systems contain small amounts of oil, and a mass transfer-based hydrate growth model is used. This paper presents a new transient hydrate formation model that predicts hydrate growth and transportability in oil- and water-dominated environments, which might be present simultaneously in oil and gas pipelines due to changes in fluid distribution in complex multiphase flow systems. Simulations of high-pressure pilot-scale flowloop experiments at different water cuts are used to verify this modeling approach. Furthermore, the proposed hydrate simulation tool is applied to analyze the flow dynamics of a subsea tieback involving hydrate formation at varying water cuts after flowloop verification. This simulation model is targeted to be widely used to simulate oil-dominated pipelines, as well as high water cut systems leading to phase inversions, and represents a step further towards the development of more comprehensive hydrate formation models.

中文翻译：

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用于预测管道中以油为主和以水为主的系统中水合物形成速率的瞬态模拟模型

摘要 深水海底设施的高压和低温运行条件经常导致天然气水合物的形成，这是最具挑战性的流动保障问题之一。不同的含水量和流线几何形状可能导致复杂的流动模式，从而导致不同的水合物形成机制。在之前的工作中，我们已经为油和水主导系统开发了水合物形成模型。以油为主导的系统模型将水相作为液滴分散在油连续层中，并使用动力学或传输模型来计算水滴界面处的水合物形成。另一方面，以水为主导的系统包含少量油，并使用基于传质的水合物生长模型。本文提出了一种新的瞬态水合物形成模型，该模型可预测在以油和水为主的环境中水合物的生长和可运输性，由于复杂多相流系统中流体分布的变化，这些环境可能同时存在于油气管道中。在不同含水率下的高压中试规模流动回路实验的模拟被用来验证这种建模方法。此外，所提出的水合物模拟工具还用于分析海底回接的流动动力学，包括在流动回路验证后在不同含水率下形成水合物。该模拟模型旨在广泛用于模拟以石油为主导的管道以及导致相转化的高含水系统，并代表朝着开发更全面的水合物形成模型迈进了一步。