Polymer adsorption models in field calculations

In a practical polymer flood calculation in a real reservoir, there will be several rock types. Not only will the permeability vary over quite a large range, but the actual details of the reservoir lithology may also differ in different regions of the reservoir. For example, there may be certain geological strata that have a higher active clay content than other strata, and this affects the polymer adsorption/retention behaviour. Permeability itself is also 

In the study by Sorbie etal. (1982), the adsorption isotherms used are based on Langmuir-type expressions. Stripping isotherms may also be used to describe the type of polymer adsorption in which the adsorption level rises very rapidly at low polymer concentration to its maximum level at which it then plateaus. It is known that the precise form of the isotherm will affect certain aspects of the flood predictions (see Section 7.5.2). For example. 

In making laboratory measurements on adsorption, it is very helpful to consider which field cores should be selected and used for most prominent attention. For example, in a multilayer reservoir from which many rock samples are available, including low-permeability cores and higher permeability material, say from a thief zone, which should be selected for most experiments This issue will be addressed in the calculations presented later in this section. 

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