Waste gas management on offshore platforms

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One of the single largest sources of greenhouse gas emissions in the production and processing of oil and gas is a result of flaring/venting. While flaring only contributes 1% of the world's anthropogenic CO2 and less than 4% of CH4 emissions, the Kyoto protocol has identified that reducing/eliminating flaring is equivalent to a 10% reduction in GHG emissions potential for industrialized countries. In addition, emissions of nitrogen and sulphur organics and polycyclic aromatic hydrocarbons (PAH) are produced from flares in significant amounts. In fact, the input into the marine environment of PAHs due to flaring from a single platform could vary from 16-2000 tonnes/yr depending on the frequency of flaring and volumes of gas. Flaring on remote/offshore platforms derives from gas co-produced with oil where economics dictate flaring is less expensive than recovery and transport (due to remoteness and limited space on the platform). This produced gas is referred to as stranded and is typically flared, re-injected or used for utilities on the platform. Re-injection is restricted in many regulatory regimes and in some deepwater wells the re-injection tended to degrade the overall oil recovery. Further, the equipment required to treat and compress the gas for re-injection can cost up to 12% of the topsides cost but provide no added value. Ultimately recovery of the all or part of the natural gas would minimize environmental impacts by not only decreasing emissions into the marine environment but also as natural gas represents a "cleaner" source of fossil fuel. A number of factors determine the option of either recovering part of the gas stream or all of the gas stream (via pipeline, Compressed Natural Gas (CNG), Liquefied Natural Gas (LNG), and Gas to Liquids (GTL)). However all options require some sort of platform gas treatment prior to transportation/storage such as condensate/NGL removal, dewpoint control, and/or contaminant removal. This focus of this work is to decrease the volume/toxicity of flared gas by removal of NGLs and contaminants.