Abstract: Method by collection and separation of oil, gas and water from an offshore oil/gas well (2) and a column (1) for usage by the same.The column (1) comprising a vertically arranged tube (3) with a lower end (8) resting on the sea bed (14) and an upper closed end (9) from which gas may be discharged by gas outlet means (6). Oil-gas mixture flowing out of a well head (22) in operation of the column (1) will be retarded by an oil column (10) in the tube (3), thereby releasing gas which is collected in the upper portion (11) of the column. Motion of the oil at the surface of the oil column (10) will be very small, oil thereby flowing over an overflow rim (15) into an overflow channel (26), from where oil is transferred to the sea surface by oil outlet means (7).The motion of the mixture may be additionally dampened by horizontal webs.The column (1) may be operated at sea depths more than 300 meters and at shallow water where the column may be constructed as part of a platform.