Patent ID: 8186442

Claim:
A system for production of oil and heavier gas fraction from a reservoir under the seabed, comprising: a field installation with at least one production well and one injection well, said at least one production well and one injection well being connected with risers to a loading and unloading station, a vessel configured to be connected to the loading and unloading station, a receival plant configured to load and unload the vessel, wherein the vessel comprises a high-pressure three-phase separator, an injection compressor, and either water cleaning equipment or water injection equipment, and the receival plant comprises a high-pressure loading and unloading mechanism, so that the vessel as connected to the field installation can load high pressure well fluid that is brought into the high-pressure three-phase separator and separated to lighter gas fractions, oil and heavier gas fractions, and water, of which oil and heavier gas fractions are configured to be brought to high-pressure storage tanks in the vessel, said high-pressured storage tanks containing high-pressure gas that thereby is displaced out of the high-pressure storage tanks and injected into the reservoir together with the lighter gas fractions, via the injection compressor, after which oil and heavier gas fractions after transport to the receival plant are configured to be unloaded by displacing the tank contents with high-pressure gas delivered from the receival plant.