湿气内腐蚀直接评价方法的现场应用

Field Application of Wet Gas Internal Corrosion Direct Assessment Method

以延长气田延气2井区BZ1-BZ4集气管线为例,采用多相流工艺计算标准化软件OLGA提供的腐蚀模块,重点分析BZ1-BZ4集气管线当前输送条件、气质、水质条件下,集气管线高腐蚀风险值的大小、出现的位置以及形成原因,并对不同腐蚀位置的风险值,依大小进行了排序,评价湿气管线运行的完整性。BZ1-BZ4集气管线高腐蚀风险点大多出现在起伏管线的上坡段,且在上坡段中部较长时间维持高风险值;集气管线高腐蚀风险点出现的位置均与高持液率、段塞流动状态、高壁面剪切力等气液两相流动参数出现的频率和位置相吻合,即在管线操作参数确定的条件下,管内气液流动状态严重影响管线高腐蚀风险点的位置和风险大小;μ-map超声波扫描检测结果与内腐蚀直接评价方法的预测结果吻合得较好。湿气内腐蚀直接评价方法可以实现延气2井区管线内腐蚀直接检测,进而替代湿气管道智能清管内检测技术。

Setting BZ1-BZ4 gas gathering line in Yan-Gas-2 well area of Yanchang Gas Field as an example,using corrosion modules provided by multiphase flow process calculation standard software of OLGA to emphatically analyze the risk values,locations and causes of high corrosion in BZ1-BZ4 gas gathering line under current transmission, air quality and water quality conditions. Meanwhile, risk values of different corrosion locations are ranked by size to evaluate the integrity of the wet gas pipeline operation.The high corrosion risk points of BZ1-BZ4 gas gathering line are mostly in the uphill section of the undulating pipeline, and the high risk value is maintained for a long time in the middle of the upper part.The positions of the high corrosion risk points of the line are all in agreement with the frequency and the position of the gas-liquid two-phase flow parameters,such as high liquid holdup,slug flow state and high wall shear stress.That is to say,under the condition of decided pipeline operating parameters,the position and the risk of the pipeline high corrosion risk point are seriously affected by the gas liquid flow state.The μ-map ultrasonic scanning test results matched well with the internal corrosion direct assessment method of forecasting results.The wet gas inner corrosion direct evaluation method can be used to directly detect pipeline inner corrosion in Yan-Gas-2 well area,which can replace the detection technology of intelligent cleaning pipe in the wet gas pipeline.