Abstract: A motion insensitive phase separator for separating oilfield production fluid phases includes a tank having a pair of opposing inlets and three generally centrally arranged outlets for different phases of a production fluid mixture fed into the tank simultaneously through the inlets. Separation media is disposed in the tank for separating the different phases of the production fluid, The separation media include antifoam media at opposite ends of the tank and further includes demisting media proximately to the median plane, on opposite sides thereof. Flow regulators, such as perforated plates, are disposed substantially vertically in the tank between the antifoam media and the demisting media. The separation media and the flow regulators are disposed generally symmetrically about a central transverse plane, thereby providing for a symmetrical flow and weight distribution for motion insensitivity.

Abstract: This invention provides a fluid-handling system for use in underbalanced drilling operations. The system includes a first vessel which acts as a four phase separator. The first vessel includes a first stage for separating solids. Oil and gas are separated at a second stage. A pressure sensor provides signals to a pressure controller, which modulates a gas flow valve coupled to the vessel for discharging gas from the first vessel. The pressure controller maintains the pressure in the first vessel at a predetermined value. An oil level sensor placed in the first vessel provides a signal to an oil level controller. The oil level controller modulates an oil flow valve coupled to the vessel to discharge oil from the first vessel into a second vessel. Water is discharged into a third vessel. Water from the third vessel is discharged via a water flow control valve, which is modulated by a level controller as a function of the water level in the third vessel.