大落差原油管道投产排水过程研究

针对最大相对高差达1 432.64 m且含大落差“U”型管段的某原油管线在油顶水投产过程中,原油与水的密度差导致油头行进停滞的问题,提出了在油水界面点附近的阀室,利用压力泄放阀排水泄压的解决方式,基于OLGA多相流瞬态模拟方法,以实际情况为例,对大落差管段的气顶水排水过程进行仿真研究。以泄流孔径为变量,重点研究了流量、压力随时间的变化规律,得到一系列可选泄流孔径及其相应的排水量、流量、压力等随时间变化的关系曲线等。结果表明,选定管段（容量约为6 376.98 m³）最大排水量可达3 375 m³,并从经济、安全、有效3个方面分析选出最佳泄流孔径为90～110 mm,与实际情况基本吻合,为解决投产过程中出现类似的异常工况提供实施依据。

Analysis of Drainage Process for Crude Oil Production Using Pipeline with Large Drop-in-height

For oil-after-water commissioning that involves a maximum drop-in-height of 1 432.64 m and uses a crude oil pipeline containing a U-shaped section with a large drop-in-height, the density difference between crude oil and water leads to stagnation issues in the oil head. To resolve this problem, we proposed to drain the pipeline and release pressure using a pressure relief valve installed in the valve chamber near the oil-water interfacial point. Based on the OLGA multiphase flow transient simulation method and taking the actual situation as an example, we simulated the gas-driven water drainage process in the pipe section with a large drop-in-height. Specifically, the simulation focused on analyzing the change in flow rate and pressure over time with varying diameters of the leakage aperture. A series of available sizes of the leakage apertures and corresponding changes in the displacement, flow, and pressure over time were obtained from the simulation. The results demonstrate that the maximum displacement in the selected pipe section (capacity≈6 367.98 m³) can reach 3 375 m³. From the perspectives of economy, safety and effectiveness, the best leakage aperture range was found to be 90～110 mm. This number was consistent with that in the actual situation. This study provides a practical basis for alleviating similar abnormal conditions in real production processes.