Abstract: A system for production of oil and heavier gas fractions from a reservoir under a seabed includes a field installation with at least one production well and one injection well, a vessel with means to be connected to a loading and unloading station, and a receival plant configured to load and unload the vessel. The vessel includes a high-pressure three-phase separator, an injection compressor, and either water cleaning equipment or water injection equipment that the vessel can load high-pressure well fluid that is brought into the separator and separated to lighter gas fractions, oil and heavier gas fractions, and water, of which oil and heavier gas fractions are brought to high-pressure storage tanks in the vessel, which high-pressure storage tanks include high-pressure gas which thereby is displaced out of the tanks and injected into the reservoir together with the lighter gas fractions, via the injection compressor.

Abstract: System for production of oil and heavier gas fractions from a reservoir under a seabed, comprising: a field installation with at least one production well and one injection well, which wells are connected with risers to a loading and unloading station, a vessel with means to be connected to the loading and unloading station, a receival plant with means to load and unload the vessel.