Abstract: System for producing de-watered oil from an underground formation to the surface, which system comprises a reception well having a substantially horizontal or inclined section for primary oil/water separation of the well fluid; a water discharge system having an upstream end that is capable of receiving during normal operation liquid from the lower region of the downstream part of the reception well; and a secondary underground oil/water separator having an upstream end that is capable of receiving during normal operation liquid from the upper region of the downstream part of the reception well, the secondary separator having an outlet for de-watered oil that is in fluid communication with the inlet of a production well and an outlet for a water-enriched component that is in fluid communication with the water discharge system.

Abstract: A gas/liquid separator comprising a vertical vessel having an inlet for a gas/liquid mixture; a gas/liquid separation device arranged within the vessel, which separation device has an inlet in fluid communication with the inlet of the vessel, and an outlet means for at least partially separated gas and liquid; an outlet for gas from the vessel, above and in fluid communication with the outlet means of the separation device; a liquid collection space in the vessel, below and in fluid communication with the outlet means of the separation device; and an outlet for liquid from the vessel, having a receiving end in the liquid collection space, wherein the gas/liquid separation device is a vane inlet device and wherein between the separation device and the liquid collection space a liquid collection promoter tray is arranged, forming a receiving area for liquid impinging on the tray from above and having a passage for liquid received on the receiving area to flow to the liquid collection space; and the use of such

Abstract: System for producing de-watered oil from an underground formation (2) to the surface (4), which system comprises a reception well (7) having a substantially horizontal or inclined section (10) for primary oil/water separation of the well fluid; a water discharge system (12) having an upstream end (13) that is capable of receiving during normal operation liquid from the lower region (14) of the downstream part (9) of the reception well (7); and a secondary underground oil/water separator (18) having an upstream end (19) that is capable of receiving during normal operation liquid from the upper region (20) of the downstream part (9) of the reception well (7), the secondary separator having an outlet (21) for de-watered oil that is in fluid communication with the inlet (5) of a production well and an outlet (22) for a water-enriched component that is in fluid communication with the water discharge system (12).