The Norwegian Statfjord licensees had to find solutions for transporting the huge volumes of oil and gas involved. While the gas went by pipeline to Germany, the stabilised crude oil was exported by specially equipped shuttle tankers to refineries and terminals throughout northern Europe. Such offshore loading failed to comply with the “10 commandments” of Norwegian petroleum policy, which said that all the country’s oil and gas production should be landed in Norway. That made it difficult to approve the system.

Loading buoys are a collective term for facilities used to transfer (load/discharge) liquids between different units, at least one of which is floating. Many varieties of such structures exist. These include catenary anchor leg mooring (Calm) designs and single point moorings (SPM), which comprise columns or towers fixed to the seabed. Some examples used on the Norwegian continental shelf (NCS) are presented below.

Accommodation facilities on all three of the Statfjord platforms have been subject to modifications large and small throughout the field’s life as a result of operational and regulatory changes.

Utilities are a collective term for the systems required to operate a platform, other than those directly involved in oil and gas production. This definition embraces direct support for the production process, general power generation facilities, and systems which sustain life and work on the installation. The latter include safety, process control, heating and ventilation, and communication equipment.

Crude oil coming up from the reservoir must be separated from the associated gas and water, and have its pressure and temperature reduced through a multistage process. Only then can it be stored in the big cells in the gravity base structure (GBS) for each platform. Processing the oil is intended to stabilise it enough to allow tanker transport.

Natural gas removed from the wellstream through pressure reduction is a mix of several different light hydrocarbons, with methane as the main component. Ethane, propane and butane are also present. Statfjord’s gas production was initially injected back into the reservoir.

Statfjord came on stream in 1979, peak annual production was achieved in 1985 and this level was maintained for eight years until output began to decline. After 2000, however, oil production declined rapidly and it was difficult to find new drilling targets with good commerciality – despite large remaining oil volumes.