Page 22 - Basic Well Log Analysis for Geologist

BASIC RELATIONSHIPS OF WELL LOG INTERPRETATION

Resistivity of the zone

Resistivity of the
Water in the zone
Water Saturation
in the zone.

a

oOo!
4

MUD CAKE

Rs

dj ADJACENT BED

VASION DIAMETERS }

_

* Fora step-contact invasion profile
(ie. no transition zone or annulus
d,.
zone). dd,

Figure 1. The borehole environment and symbols used in log interpretation. This schematic diagram illustrates an idealized
version of what happens when fluids from the borehole invade the surrounding rock. Dotted lines indicate the cylindrical
nature of the invasion.
Courtesy, Schlumberger Well Services.
Copyright 1977, Schlumberger.