Mud removal and cement placement during primary cementing of an oil well

摘要

A two-dimensional model is derived of the displacement flow that occur during primary cementing of oil and gas wells. The displacement geometry is a long narrow eccentric annulus, between the casing and the rock formation. The model consists of a series of first-order convection equations for the fluid concentrations and a quasi-linear Poisson-type equation for the stream function. Coupling is through the velocity field and the concentration-dependent fluid properties. A range of computed results from this model is presented. One simulation illustrates how a channel of mud Can be left behind on the narrow side of the annulus.