Polymer recovery mechanisms in simple stratified systems

7 Polymer recovery mechanisms in simple stratified systems 

An important application of polymers in several areas of the world is in the improvement of waterflooding performance in highly inhomogeneous reservoirs. In particular, polymers can reduce the harmful effects of high-permeability layers in a vertically stratified system and so reduce watercut and improve vertical sweep efficiency. Polymers can act by a combination of two mechanisms  

This section will examine in detail the mechanisms of incremental oil recovery in the polymer flooding of heterogeneous (layered) reservoirs. It is shown 

This issue is discussed and illustrated using simulation results from a very simple two-layer reservoir with high- and low-permeability regions. This allows the illustration of the effects of a number of parameters on the basic fluid cross-flow mechanisms which occur. The dependence of cross-flow on features such as reservoir permeability contrast, vertical/horizontal permeability ratio (kjkx) and the relative thickness of the layers is examined. Although the cross-section is sufficiently simple to allow the performance of a wide range of sensitivities, it does capture the basic flow mechanisms very satisfactorily. This is shown later in results from much more realistic models which have been taken from real field systems. 

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