Historical production

The production (well stream) from different reservoirs contains oil, gas and water in various combinations. To get marketable products, the production from the reservoirs must be separated and treated. The production from different reservoirs varies from oil with low gas content to almost dry gas (methane with only small amounts of other gases).

Crude oil is a fluid that is a combination of different types of hydrocarbons. The composition varies from field to field, and the quality of the oil, including how light or heavy (viscous) the oil is, depends on the composition of the hydrocarbons as well as the contents of other substances, such as wax and sulphur.

Rich gas, or crude natural gas, is a mixture of various gases. When necessary, the gas is separated from the oil before the rich gas is treated in a processing facility that separates the dry and wet gas components. Dry gas is often referred to as natural gas, and consists mainly of methane, but also a little ethane.

Wet gas, or NGL (Natural Gas Liquids), consists of a mixture of heavier gases (ethane, propane, butanes and naphtha). In addition there are heavier condensates which some classify as a separate product. Naphtha and condensate are liquid at room temperature, while the lighter wet gas components can be made liquid either by cooling or by adding pressure.

Not all gas that is produced is sold. Some of the gas is used to generate power on the fields, and small amounts are flared for safety purposes. On some fields, gas is reinjected into the reservoirs. Reinjection is often used to maintain reservoir pressure and displace the oil. This results in efficient recovery of the oil, and the gas is stored for possible recovery in the future.

There is a delay of about two months in the production figures. Test production is not included in the production figures. All numbers below are in million Sm³ o.e., and natural gas is not normalised to 40 MJ/Sm³.