KING ABULAZIZ UNIVESITY
FACULTY OF EARTH SCIENCES
DEPT. OF GEOPHYSICS
GEOELECRTIC METHODS
EGP431 LABORATORY SECTION
LAB. NO. 3
1) Derive the geometrical factor for the wenner and schlumberger cofigration?
2)2)
2) Find the potential difference between points P1 and P2 for cases (a) and (b).
Assume a current of 0.6 ampere.
C1
Source
C2 Sink
4) Derive the geometrical factor for the Lee-Partitioning configuration?
The Lee-partitioning electrode is the same as the wenner array, except that an additional
potential electrode O is placed at the center of the array between the potential electrodes
M and N. Measurements of the potential difference are made between O and M and
between O and N.
KING ABULAZIZ UNIVESITY
FACULTY OF EARTH SCIENCES
DEPT. OF GEOPHYSICS
GEOELECRTIC METHODS
EGP331 LABORATORY SECTION
LAB. NO. 6
1) sketch a set of three curves following model:
ρ 1 (Ωm)
200
200
200
ρ 2 (Ωm
10
10
10
Depth to the interface (m)
5
10
20
Use RESIS program to calculate the possible apparent resistivity curve. What are the
factors that are controlled on the apparent resistivity curves (resolution od the DC
resistivity method)?
Which do of the three cases that the DC resistivity method can resolve their physical
properties and why?
2) Sketch three curves for which the interface of the previous model remain the same (
depth of the interface is 20m) and the resistivity of the shallow layer is constant at 10
Ωm, but the resistivity of the deeper layer takes on values of 100 Ωm, 200 Ωm, and 500
Ωm. Discuss the factors that affect on the resolution of the DC resistivity method and
how to over come this problem?