海底埋地管道启输计算模型的建立

目前的海底埋地输油管道启输计算模型没有具体分析海水本身自然对流换热对管道启输的影响,启输计算模型能否应用于海底埋地输油管道启输计算需要实际投产来验证.因此急需研究海底输油管道预热计算模型满足海上油田开发的需求.对海底埋地输油管道进行了传热分析,建立了海底埋地输油管道三维物理模型,分析了海水本身自然对流换热对管道启输的影响情况.通过处理物理模型将管道启输传热模型简化为一维圆环传热模型,并进行了模拟计算和试验验证.模拟计算和实验研究对比表明:①当海水底流流速小于1.5m/s时,在此区域内海水自然对流换热对海底输油管道传热影响可以忽略不计.②海底输油管道正常矩形散热区域转换为圆环区域后其散热量基本不变,可见海底输油管道转化为一维模型是可行的.③在验证稳定状态沿程温降的过程中,发现各个测温点的绝对误差不超过0.1℃,说明该启输计算方法具有很高的置信度.

Establishment of the model for the Starting-up calculation of seafloor oil buried pipeline

The natural convection of seawater is not considered in the most of the models for the starting-up transmission heat transfer calculation of seafloor buried oil pipeline.Whether these models can be used needs practice to verify.In order to meet the need of offshore oilfield development,the heat transfer of seafloor buried oil pipeline is analyzed,and a three-dimensional physical model and mathematical model for seafloor buried oil pipelines are established.The effect of seawater natural convection on the starting-up transportation of the seafloor buried oil pipeline is analyzed.The mathematical model is simplified to a one-dimensional annular heat transfer model by the treatment of the physical model,and it is simulated and verified by experiments.The contrast of simulation calculation result and certification experimental result shows that,(1) the effect of seawater natural convection on the starting-up transportation of the seafloor buried oil pipeline can be neglected when the flow velocity of seafloor seawater is less than 1.5m/s;(2) the heat dissipating capacity of the seafloor buried oil pipeline does not basically change when the rectangular heat radiating area of it is simplified into the annular heat radiating area,which shows that the simplification of the mathematical model is feasible;(3) the temperature error at all the temperature measuring points along the pipeline is less than 0.1℃,which also shows that the simplification of the mathematical model is correct.