ABSTRACT
In crude oil production, gas, oil, and co-produced water are mixed due to pressure drop and high shear forces as the fluid passes the wellhead and various choke valves from the reservoir to the separation facilities. The primary task at the oil producing facility is to separate gas from liquid and oil from water. The oil and water mixture is typically processed through a separation train of two or three separators, where water is removed. The produced water contains dispersed oil droplets, which need to be removed in order to meet environmentally based, governmental demands on water quality before discharge to sea. The produced water is therefore cleaned through additional separators, cyclones, etc. before it is disposed to sea or re-injected into the reservoir.
One of the major factors influencing performance in both hydrocyclones and traditional flotation cells/plate separators is the droplet size distribution of the dispersed phase. The separation of smaller droplets is slower and more difficult. In the design and evaluation of oil-water separators in the oil industry, information concerning the sizes of droplet is critical [1]. Droplet size is an important parameter in equations describing droplet movement, such as Stokes’ law for gravity induced sedimentation/creaming [2], the Stokes-Einstein equation for diffusion [3], and in equations describing sedimentation and coalescence profiles [4-6].
