Pore-doublet model

The pore doublet model was introduced by Moore and Slobod in 1956 (i), and has been critically reviewed by Chatzis and Dullien (2). In this model, two capillaries of different diameters are connected at the inlet and outlet ends to create an idealized model of a pore structure. Initially, the doublet is full of oil, and water with viscosity the same as that of the oil flows in from one end (Figure la). As the water continues to flow, three outcomes are possible ... 

Figure 1. Pore doublet model. (Reproduced with permission from reference 3. Copyright 1989 Prentice Hall.)...

The main objective of surfactant flooding is to reduce residual oil saturation, which is closely related to capillary number. Therefore, the concept of capillary number is discussed first. Analysis of the pore-doublet model yields the following dimensionless grouping of parameters (Moore and Slobod 1955), which is a ratio of the viscous-to-capillary force ... 

Two models help to explain the mechanisms by which oil is entrapped in porous media the pore doublet and the snap-off models. 

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