Abstract
A continuously undulating pipeline results in the accumulation of air at high points and liquid at low points during commissioning, hindering the process, and impacting oil product quality. Cavitation may occur at the crossover point, especially for high saturated vapor pressure oils, potentially causing water strikes and pipeline damage. This study focuses on the BZ pipeline, transporting high saturated vapor pressure condensate in a varied terrain. It proposes the “oil injection after water isolation section” commissioning method and develops 20 commissioning schemes based on site conditions. A multiphase flow simulation model investigates the effects of pipeline flowrate and water injection length on start pressure, high point liquid retention, crossover point pressure, low point liquid retention, and liquid accumulation time. A preferred commissioning scheme suggests a pipeline flowrate of 192 m3/h–240 m3/h and a water injection length of 133 km. Commissioning schematics and operation schedules are devised accordingly. Optimization shows that increasing pipeline flowrate reduces low point fluid accumulation time. For downhill pipeline sections, extending water injection length does not enhance liquid retention at crossover points or improve pipeline exhaust, risking high pressure at low points. During oil–water injection transitions, maintaining a high delivery rate minimizes pressure fluctuations due to density differences. Following this scheme, pig wear along the BZ pipeline was even, and crossover point 2# and valve chamber No. 10 showed good exhaust conditions. Optimizing key parameters and commissioning scheme formulation effectively guide BZ condensate pipeline commissioning, ensuring safety.
