Multiphase separator, and method of separating a multiphase fluid

The present invention provides a multiphase separator for separating a multiphase fluid produced by one or more oil wells, the multiphase separator comprising: a separating vessel, comprising an inlet chamber and an oil chamber for collecting oil at least partially separated by a barrier; an inlet for introducing the multiphase fluid into the separating vessel; wherein the oil chamber is positioned on the opposite side of the barrier to the inlet; a gas outlet configured to collect gas separated from the multiphase fluid; an oil outlet configured to collect oil, separated from the multiphase fluid, from the oil chamber; a water outlet configured to collect water separated from the multiphase fluid; and a gas and water mixture injector configured to inject a mixture of pressurized gas and water in a lower portion of the separating vessel.