Simulation and Replication of High-Pressure Hydrocarbon Pipeline Commissioning under Large-Drop Undulating Environments

The BoZi (BZ) hydrocarbon pipeline is a large descending pipeline that transports a mixture of condensate and light hydrocarbons. It is prone to evaporation during transportation, posing safety risks during commissioning. In this study, a transient hydraulic model of pipeline commissioning was developed to formulate the commissioning plan and operational procedures for the BZ pipeline. Parameters such as oil, gas, and water distribution; pig velocity; pressure profile; and liquid retention were simulated, assuming no gasification at high points and no overpressure at low points. During actual commissioning, due to fluctuations in hydrocarbon production at the first station, frequent adjustments to the main valve opening percentage, occurring 74 times, delays in switching between water and oil injection, and constraints on emission pipelines at the last station, the boundary conditions of the production calculation model were adjusted to reflect real production conditions. The water injection and oil injection processes during actual commissioning were completed, and the travel times of air–water and water–oil pigs were calculated. The deviation between calculated and monitored pressure along the pipeline was less than 1.5%, with no gas blockages or flow disruptions during commissioning. The predicted commissioning time was 95.4 h, which was 0.1 h less than the actual time. Through experimental validation, this study provides a practical solution for improving the efficiency and safety of pipeline commissioning. It helps engineers to study operational problems in advance of the commissioning with OLGA simulation software, increase the success rate, and minimize the environmental impact, thus advancing the development of pipeline commissioning technology.