Petrophysicists like patterns and trends. It’s a sure and a quick way to evaluate a reservoir.

They make it easier for us to establish, correlate and predict the outcomes.

Like in a quick log analysis, if we know that the density-neutron are overlaying, it means that we are in an oil or water bearing zone. If the density and neutron separate, we are in a gas zone.

Even in core analysis, we join and lump those tiny dots that represent phi, or Pc, or k so we can relate them to another properties. For example, we use a phi-k relationship to estimate permeability or to cluster rock types using RQI or FZI.

There are two fundamental differences between a pattern and a trend.

Simply put:

A trend is a direction.

A pattern is a shape.


What is a trend?

A trend is the general direction of which something is changing. The three basic trends are up, down and sideways. Trends may be discovered in the short, medium and the long terms. A trend is always following a direction. Like resistivity going up is a trend.


What is a pattern?

A pattern is an occurrence of data that repeats in a recognizable way. A pattern has similar characteristics.

The tiles in your bathroom has a certain pattern even if you see just a part of your bathroom floor. So you know how it would go on without actually seeing it.

Like when you are coming up with formation tops, as you are drilling inside different formation, you'll know which formation comes next.


Once you spot the patterns or trends, you can establish specific reference scenarios for your well logs. This is the basis of The Six Ko Ko Rules and The Super Quick Log Analysis.

Take a look.