Flow and displacement of waxy crude oils in a homogenous porous medium: A numerical study

Abstract

In the present study, the displacement of waxy crude oils is numerically/theoretically investigated in the water-flooding operation. The oil was assumed to obey the Houska model-a robust thixotropic fluid model which is often realized to well describe the rheology of waxy oils in different parts of the world. Based on the concept of effective viscosity, a modified version of the Darcy's law was developed for this particular fluid model in order to describe its flow through a homogenous porous medium. Use was made of numerical and theoretical methods to study the displacement of Houska fluid by water in two benchmark problems: (i) the Buckley-Leverett problem, and (ii) the five-spot problem. It was found that the yield stress of the Houska fluid being variable (i.e., shear-and time-dependent) has a retarding effect on the water breakthrough phenomenon. The breakdown-to-rebuild ratio in the Houska model was shown to play a key role in the water breakthrough phenomenon provided that it is very large. At this extreme, however, the effect was attributed mostly to the shear-thinning behavior of the Houska fluid rather than its thixotropic behavior. In fact, at sufficiently low breakdown-to-rebuild ratios (i.e., when fluid's thixotropy becomes progressively more important) it had no significant effect on the water breakthrough phenomenon. Therefore, it is concluded that in competition with shear-thinning, the thixotropic behavior of Houska fluid plays a secondary role, if any, in the water-flooding operation.

POD-Galerkin Model for Incompressible Single-Phase Flow in Porous Media

“…The distribution of permeability is not uniform with a small value in the "H"-shape zone and a large value in other zone, but the two components kxx and kyy are always equal to each other. Sample cases are designed as p 1 = {50, 55} mH 2 Pressure and velocity coincide very well with each other for both POD and FDM in the two cases with the maximum and minimum deviations (Fig. 11).…”

“…Fluid flow in porous media is a very important physical phenomenon in many aspects of engineering, such as catalytic reaction in chemical engineering [1], transport of oil/gas/water in petroleum engineering [2], etc. Numerical simulation is needed to predict the flow details [3].…”