Basic Petrophysics

Lecture Presentation

Carlos Torres-Verdín, Ph.D.Assistant Professor

PGE368Fall 2001 SemesterSeptember 21, 2001

Basic Pore Space Properties

Definition of Porosity

Range of Porosity Values

Range of Porosity Values

Trends of Porosity

Porosity vs. Grain Diameter

Porosity vs. Depth

Porosity vs. Depth

Porosity of a Sphere Packing

Types of Sphere Packing

Variations in Grain Size

Porosity of Sphere Packings

Fluids in the Pore Space

Fluids in the Pore Space

Permeability

Methods Used for Measuring Permeability

Effect of Grain Size and Shape on Permeability

Permeability Tensor

Spherical Permeability

Tensor vs. Scalar

Permeability Trends

Permeability vs. Porosity

Permeability vs. Porosity and Grain Size

Permeability vs. Pore Size

Shale Content Reduces Permeability

Summary

Absolute and Relative Permeability

Pressure Dependence of Permeability

Specific Internal Surface

Specific Internal Surface

Pore-Filling Kaolinite

Surface Area of Common Rock Types

Surface-to-Volume Ratio

Relationship Between Porosity, Specific Surface,and Tortuosity

Relationship Between Porosity, Permeability, and Specific Surface Based on Models

Fundamentals of Capillary Pressure

Capillarity and Pore Diameter

Capillary Pressure Curves

Capillary Pressure Curves

Capillary Pressure Curves vs. Permeability

Directions of Saturation Change

Capillary Pressure Curves: Water-Wet and Oil-Wet

Capillary Pressure Curves

Summary

Summary

Acknowledgements

• Baker Atlas