Offshore hydrocarbon infrastructure will produce and transport fluids (comprising gas, condensate, and produced water) from the subsea wells to the platform via subsea flowlines, the gas and condensate is dehydrated and dewatered at the platform, and the dry gas and condensate routed through the trunkline to the onshore endpoint.
Before steady-state production, initial start-up and testing processes also occur, with well clean-ups at the platform and testing of the platform systems and equipment, as production is gradually ramped up to steady-state capacity and normal operations. Testing of platform systems may also be performed by using back-flow gas (via the onshore plant and the trunkline), prior to well production.
The description of the petroleum activity is presented in four sections including: the hydrocarbon system; the platform; inspections, maintenance and repairs; and field support. The hydrocarbon system is the infrastructure (including the wells, flowlines and trunkline) used for gathering and transporting fluids to and from the platform. The platform includes various hydrocarbon processing and utility systems, as well as accommodation facilities, control room and helideck. Inspections and maintenance of the hydrocarbon system will typically be performed by vessels and ROVs (or similar). Field support includes the use of platform supply vessels, helicopters for personnel transfers, and inspection, maintenance and repair (IMR) vessels.