Oil, water, gas and solid particle separation in oil and/or gas production

An apparatus for separating oil, water and gas from a hydrocarbon-containing fluid produced from an oil and/or gas production facility, the apparatus comprising:

• a. a separation tank for separating a multiphase hydrocarbon-containing fluid comprising oil, water and gas into its constituent oil, water and gas phases, the separation tank including a first inlet for the hydrocarbon-containing fluid, a second inlet for gas and, connected to the second inlet, a gas fluffer for passing gas bubbles through an oil/water mixture in a reservoir of the separation tank to collect droplets of oil entrained within the water;
• b. a first separator provided upstream of the separation tank, the first separator comprising an inflow conduit for the hydrocarbon-containing fluid, a first outlet of the first separator communicating an upper part of the first separator with the second inlet to convey gas separated from the hydrocarbon-containing fluid to the gas fluffer provided inside the separation tank, and a second outlet communicating a lower part of the first separator with the first inlet of the separation tank to convey liquid phases of the hydrocarbon-containing fluid to the separation tank.