This graph can be used to indicate whether a formation is homogeneous or heterogeneous.

This graph can be used to indicate whether a formation is homogeneous or heterogeneous.

• A. Capillary Pressure Curve
• B. Relative Permeability Curve
• C. Pressure-Volume Diagram
• D. Capillary Pressure vs Water Saturation

Answer: (D)

Capillary pressure is controlled by the size and distribution of pores and throats and how wetting occurs in the rock. When a formation is uniform, the capillary entry pressure and the Pc-Sw relationship are essentially the same throughout, so a single Pc versus water saturation curve can represent the whole formation. If the formation is heterogeneous, different zones or layers have different pore size distributions and wettability, so their Pc-Sw curves shift or take on different shapes. Plotting capillary pressure against water saturation for various intervals will reveal these differences as distinct curves or offsets rather than one uniform curve. That direct link between the capillary behavior and pore structure makes the Capillary Pressure vs Water Saturation graph the best way to indicate heterogeneity.

Capillary pressure is controlled by the size and distribution of pores and throats and how wetting occurs in the rock. When a formation is uniform, the capillary entry pressure and the Pc-Sw relationship are essentially the same throughout, so a single Pc versus water saturation curve can represent the whole formation.

If the formation is heterogeneous, different zones or layers have different pore size distributions and wettability, so their Pc-Sw curves shift or take on different shapes. Plotting capillary pressure against water saturation for various intervals will reveal these differences as distinct curves or offsets rather than one uniform curve. That direct link between the capillary behavior and pore structure makes the Capillary Pressure vs Water Saturation graph the best way to indicate heterogeneity.