|BRITAIN'S OFFSHORE OIL & GAS
Functions of a Production Platform
Oil platforms are an industrial town at sea, carrying the personnel and equipment needed for continuous hydrocarbon production. The most important functions are drilling, preparing water or gas for injection into the reservoir, processing the oil and gas before sending it ashore, and cleaning the produced water for disposal into the sea. Power is generated on the platform to drive production equipment and support life. All production systems are constantly monitored for leaks, since oil and gas are hazardous and extremely flammable.
The top of each production well sprouts a branching series of pipes, gauges and valves called the 'Christmas tree' (see F97, page 55). At this point, crude oil is a hot, frothy, corrosive, high-pressure fluid containing gas, water and sand. After separation, the crude oil is metered and pumped into the pipeline, or stored until sent ashore by tanker. The gas separated from the oil may be used for fuel, or compressed and piped to shore or re-injected into the reservoir. Any gas that cannot be used or piped ashore must be burnt in the platform's flare. Very little gas is now flared. Processing systems for the gasfields of the southern North Sea are relatively simple. Any liquids dissolved in the gas are removed, then the gas is compressed, cooled, dehydrated and metered before being piped to shore.