An apparatus and method for separating water from an oil-water influx are provided. The apparatus includes a separation vessel having an inlet, an oil collection portion at its upper end, and a water collection portion at its lower end. Multiple high voltage tubes, each containing an electrode, are located within the oil collection portion. These high voltage tubes are staggered in length and held in place by perforated plates. The oil-water influx flows through the inlet of the vessel into the high voltage tubes, where it is subjected to an electrostatic field. The electrostatic field causes water droplets in the influx to coalesce and form a water out-flux which flows downwardly into the water collection portion of the vessel. The remaining stream of dehydrated oil flows upwardly to the upper outlet end. The oil collection portion of the separation vessel may be oriented vertically or at an angle.