N360 Quantitative Log Analysis and Petrophysics

Course Facts

Course Code:
5 days
4.0 Continuing Education Units
40 Professional Development Hours
Certificate Issued Upon Completion


The course introduces the principles and practice of petrophysics as applied to conventional reservoir rocks (clastics and carbonates). It defines the petrophysical properties: porosity, permeability and water saturation and goes onto explain what controls them and how they can be reliably estimated. The course also considers some of the more artificial properties that are based on the above and shows how they are used to characterize petroleum reservoirs.

Duration and Training Method

A five-day classroom course, comprising lectures supported by exercises of varying complexity. Most exercises will use real data from a variety of different reservoir types. All exercises can be completed using calculators and graphs (computers and special software are not required).

Participants will learn to:

  1. Be able to define porosity, water saturation and permeability and appreciate the difference between total and effective porosity models.
  2. Understand how porosity is measured in the laboratory and how it can be estimated from density and other physical properties measured by logging tools.
  3. Have a qualitative understanding of how porosity tools work: density, sonic, neutron porosity and NMR.
  4. Define electrical resistivity and what determines it in porous solids (Archie equation).
  5. Understand how resistivity is measured in the borehole and how resistivity measurements can be used to estimate water saturation.
  6. Appreciate what controls permeability, how it is measured and how it determines deliverability in wells.
  7. Calculate reservoir average properties and use them to characterize reservoirs.
  8. Have a qualitative understanding of what controls the distribution of oil and gas in a reservoir.

The course starts with an introduction which includes an overview of the course and some useful tools and techniques. The rest of the course goes through the outputs of a petrophysical interpretation in the order they are typically generated: shale volume, porosity, saturation and permeability. Each property is defined, before explaining how it is measured on rock samples and why it is important. At the same time the logs that are most commonly used to estimate it are introduced and the way(s) they are transformed is described.

Day 1:
1.1 Petrophysical properties and data
1.2 Physical Properties of Rocks
1.3 Measuring porosity and permeability on core samples
1.4 Fundamentals of Logs and Log Analysis
1.5 Some Useful Tools and Techniques

Gamma-ray, SP and Shale Volume.
2.1 Clay minerals and why they are important in petrophysics
2.1 Shale and Clay Volume
2.2 Natural Gamma-ray Activity
2.3 SP

Day 2:
Density and Porosity
3.1 Introduction
3.2 Density and the density log
3.3 Porosity from Density
3.4 More on Porosity

More Porosity Logs
4.1 Neutron Porosity
4.2 Sonic
4.3 NMR
4.4 Estimating porosity and shale volume from sonic and neutron logs
4.5 Combining Measurements

Day 3:
Resistivity and Saturation

5.1 Introduction
5.2 Resistivity Tools
5.3 Water Saturation
5.4 Resistivity and Saturation: Archie equation.
5.5 Modifi cations to the Archie equation (conductive minerals)

Day 4:
Hydrocarbon Eff ects on Logs

6.1 Specifi c eff ects of hydrocarbons on logs
6.2 Accounting for Hydrocarbon Eff ects
6.3 Accounting for Invasion
6.4 Fluid Substitution

7.1 Introduction, diff erent types of permeability
7.2 Controls on permeability
7.3 Estimating Permeability from Logs

Net, Pay and Averaging
8,1 Why Average?
8.2 Cut-off s and how they are chosen
8.3 Problems.
Brief introduction to uncertainty

Day 5:
Fluid Distribution: Controls and Models

9.1 Introduction and Fundamentals
9.2 Water in Porous Rocks
9.3 Measuring Capillary Pressure Curves.
9.4 Real Fluids in Real Rocks
9.5 Contacts and Free water Level
9.6 The Saturation Height Function
Conclusion and the Future

Who should attend

The course is designed to give participants an appreciation of the practice of petrophysics. Anyone who uses petrophysical properties in their day to day work would benefit from attending. Petrophysicists at the start of their careers would also benefit from attending but it is not intended to cover the more advanced tools and techniques.

Prerequisites and linking courses

There are no prerequisites for this course.

Click on a name to learn more about the instructor

Martin Kennedy