Research subject: Oil and gas transmission pipelines are considered critical energy transportation arteries and are exposed to various threats. Natural phenomena, such as earthquakes and floods, as well as human-related factors, including unsafe excavation activities and operational failures, are among the main causes of leakage and performance disruptions in transmission lines. The 16-inch Mansouri oil field pipeline, with a length of 33 km, transports 75,000 barrels of crude oil per day from the field’s gathering center to the Ahvaz booster pump station. In this study, the pressure drop along the pipeline and the volume of fluid released into the environment due to leaks of different sizes were calculated using transient flow simulation.
Research approach: Transient multiphase flow simulations were performed using the OLGA simulator. Operational and field data were used to construct the initial model. The initial hydraulics of the pipeline model were calibrated by adjusting parameters such as internal pipe roughness, fluid viscosity, and gas–oil ratio (GOR) to minimize deviation from actual operating conditions. The calibrated model was then used to predict pressure drops and leakage flow rates. The modeling results can support the design of leak detection and warning systems, particularly real-time transient model–based systems.
Main results: The results indicate that, for leak diameters of 1 cm, 10 cm, and a full-bore rupture, the pressure drop rate at the pipeline inlet is approximately 0.0001 bar/s, 0.06–0.28 bar/s, and 0.25–5 bar/s, respectively. These pressure drop rates are critical for determining the automatic shutdown time in real-time transient model (RTTM) systems.