Achieving Zero Flaring in Offshore Gas Fields

Abstract

Abstract The facilities associated with producing nonassociated gas from offshore fields consist of wellheads and tie-in platforms, which are equipped with flare systems. At wellhead platforms, the flares are maintained where a high integrity protection system (HIPS) is provided at each wellhead for over pressure protection. In addition, continuous flares are usually provided at tie-in platforms as another layer of protection. The initiative is to convert tie-in flares to maintenance, which will eliminate continuous flaring and further minimize the emissions. There are three protection layers consisting of Emergency Shutdown system (ESD) system, a HIPS system, and mechanical relief valves with partial flaring at the tie-in platforms, which activate in case both ESD and HIPS protection systems at the wellhead platform do not respond to an overpressure condition. Normally the original design will have the relief system and continuous flaring at the TPs manifolds as another protection layer. However, the HIPS design stated that the design shall ensure that HIPS alone bridges the safety risk gap. A methodology and comprehensive engineering assessment was conducted to evaluate the risk for modification of continuous flare to maintenance flare considered with partial flare and without partial flare. The study concluded that continuous flaring is no longer required and the HIPS alone is sufficient for over-pressure protection. This initiative will eliminate thousands of tons of CO2 emitted to the environment from the continuous flaring. The total cost savings analysis includes gas value creation and maintenance cost savings such as propane (fuel) burning reduction, flare tip replacements, and maintenance costs.