| Summary: | Above sea gas dispersion resulting from subsea release could cause explosion risk to a nearby offshore platform. Past researchers performed a CFD-based assessment of above sea gas dispersion under the varying sea and environment conditions, but the resulting expected overpressure consequences due to the potential ignition of dispersing flammable on an offshore platform under such varying conditions were not investigated. Overpressure estimates under varying sea and weather parameters could support the practitioners in determining the most critical conditions that correspond to the worst consequences on the offshore platform thus, the research could contribute to process safety. Therefore, in this study, above sea gas dispersion under varying wind speeds in range 2-6 m/s and sea surface release rates of 390 kg/s and 872 kg/s were performed using a Fire Dynamics Simulator (FDS), and expected overpressure consequences in each case are estimated based on the flammable concentration distribution on the platform. It was found that low wind speed and less release rate do not pose a danger to the platform. However, compared to the low wind-low release rate, 35% greater platform area was covered by flammable gas cloud at a high wind speed of 6 m/s and a high release rate of 872 kg/s. This could cause overpressure of 70 kPa in 7.5% of the platform region, which is identified as the most dangerous release rate and wind speed condition. It is suggested that the operators on the offshore platform take special care in high wind and release rate scenarios to avoid flammable cloud accumulation and resulting overpressure consequences.
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