Correlation of Factors Affecting the Gravity Separation of Crude Oil-Water Mixtures

This basic investigation was prompted by the lack of a scientific method for determining the amount of settling surface needed to permit the gravity separation of oil and water for a particular set of conditions, i.e., oil gravity, per cent water cut, and oil viscosity. Consequently, both static and dynamic separation tests were performed, in order to determine the relative importance of the variables involved. As a result of this work, a correlation is presented that enables one to predict the length and diameter of settling vessel needed. Theory Inasmuch as the settling of water particles in oil is similar to the gravity separation of solid particles in a fluid, it was felt that a modified application of Stokes' law would establish the general relationship of the variables. In order to employ this simple approach, it is convenient to assume that:The water droplet is spherical, incompressible, and nonporous.Gravity is the only accelerating force present.The particle is free moving and is not hindered in any manner.The oil is incompressible and of such volume that no "wall effect"is encountered.