Experimental investigation and modelling of heat loss mechanism from offshore buried pipelines
Experimental investigation and modelling of heat loss mechanism from offshore buried pipelines
复制标题
海上埋地管道热损失机制的实验研究和建模
DOI：
--
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
S. Chakraborty
中科院分区：
文献类型：
--
作者：
S. Chakraborty
海底埋地管道热损失的模拟是石油和天然气工业的主要关注点之一。由于北极地区恶劣的环境条件和危险性，海上石油和天然气生产以及埋地管道的热模拟是具有挑战性的任务。当流体温度下降时，原油的重组分开始以蜡晶形式沉淀。当天然气在高压和低温下与自由水结合时，也会形成气体水合物。海底埋地管道在海底以热传导和自然对流的形式存在大量的热损失。在回填土松散或桑迪的地方，后者可能变得更加突出。
埋地管道热损失计算中，理论形状因子模型被广泛采用。进行了几个基准测试，以确保使用理论形状因子模型的测试的有效性，该模型取决于周围介质的热流量、热导率和几何形状。
周围介质的饱和度对流体在回填土中的热行为有重要影响。本研究提供了几种稳态和瞬态响应分析，描述了一些有影响的岩土参数沿着以及不同参数（如埋深、回填土、沟槽几何形状等）的测试程序。
进行了几次关闭（冷却）测试，以显示干燥和饱和砂介质中的瞬态响应。本研究的成果将为海底管道设计、海底埋地管道热损失以及减轻蜡和水合物等流动保证问题的有效模型提供有价值的实验数据和数值预测。
Modeling of heat loss from offshore buried pipelines is one of the major concerns for oil and gas industries. Offshore oil and gas production and thermal modeling of buried pipelines in Arctic regions are challenging tasks due to the harsh environmental conditions and hazards. Heavy components of crude oil start to precipitate as wax crystal when the fluid temperature drops. Gas hydrates also form when natural gas combines with free water at high pressure and low temperature. Significant heat loss may occur from offshore buried pipelines in the forms of heat conduction and natural convection through the seabed. The later can become more prominent where the backfill soil is loose or sandy.
Theoretical shape factor model was widely utilized to estimate heat loss from buried pipelines. Several benchmark tests were performed to ensure the validity of the test using theoretical shape factor models which depend on the amount of heat flow, thermal conductivity and geometry of the surrounding medium.
The degree of saturation of surrounding medium can play a significant role in the thermal behavior of fluid traveling through the backfill soil. This research presents several steady state and transient response analysis describing some influential geotechnical parameters along with test procedures for different parameters such as burial depth, backfill soil, trench geometries, etc.
Several shutdown (cooldown) tests were performed to show the transient response in the dry and saturated sand medium. The outcomes of this research will provide valuable experimental data and numerical predictions for offshore pipeline design, heat loss from buried pipelines in offshore conditions, and efficient model to mitigate the flow assurance issues e.g. wax and hydrates.