南堡油田海底管道砂沉积预测与模型检验

Sand deposit prediction and model checking of submarine pipeline in Nanpu Oilfield

介绍了几种砂沉积预测模型,包括均匀颗粒计算模型杜兰德公式以及非均匀颗粒计算模型卡察斯基公式、舒克公式、王可钦公式。以南堡35-2油田WHPB-CEP海底混输管道为例进行砂沉积预测计算,采用激光粒度仪对积砂进行粒度分析,验证了预测结果的可靠性。按照均匀颗粒计算得砂沉积的临界流速为1.931m/s,按照非均匀颗粒计算得砂沉积的最小临界流速为0.193m/s,均大于根据实际工况条件计算得到的水相流速0.12m/s,说明海管以目前的工况运行,存在砂沉积问题。积砂粒径的平均值为178.36μm,远大于滤砂网孔径对应的粒径63μm,说明经过长期运行,滤砂网磨损,导致过滤孔径增大。提出了降低清管器卡堵风险、防止携砂过度沉积的具体方法。

Several models for sand deposit are given,including uniform particle calculation model-Durand formula and non-uniform particle calculation model-Kazanskij Formula,Shook Formula and Wang Keqin Formula.Prediction calculation for sand deposit is made by authors with a case of Nanpu 35-2 Oilfield WHPB-CEP submarine mixed transferring pipeline,and particle size analysis is performed for sand deposit with a laser particle sizer to verify the reliability of predicted results.The critical velocity for sand deposit is 1.931 m/s if it will be calculated as uniform particles,and the minimum critical velocity of sand deposit is 0.193 m/s if calculated as non-uniform particle,both of which are greater than the calculated 0.12 m/s-water-phase flowrate according to actual working conditions,showing that the problem of sand deposit will occur under current operation conditions for the submarine pipeline.The average particle size of deposited sand is 178.36 μm,far greater than 63 μm of corresponding hole size of sand filter mesh,showing the sand filtration mesh will be damaged due to wear and thus cause the increase of hole diameter for filtration.It puts forward the method for decreasing the risk of pig blocking and avoiding too much deposit of carrying sand.