This document discusses electrical logs, including self potential (SP) logs. It defines the SP log as measuring the voltage difference between a downhole electrode and a surface electrode. The objectives are to understand the physical principles, interpretation for lithology and properties, and corrections needed. The SP log is used to identify impermeable zones like shale and permeable zones like sand, detect boundaries of permeable beds, and determine formation water resistivity and shale volume. It further explains the theory of measurement, factors affecting readings, and gives more details on the definition and general uses of SP logs.

2. Electrical Logs
- Self Potential log,
- Conventional resistivity logs ,
- Focused resistivity Logs,
- Microspherically focused logs,
- Induction logs.

3. Self (Spontaneous) Potential (SP) log
Objectives
• To understand the physical principles behind
the operation of spontaneous potential (SP)
logging.
• To learn how to interpret SP logs in terms
of lithology and petrophysical properties.
• To understand what corrections needed to be
applied to SP log before using it for
interpretation.

4. * Definition.
* Units& Presentation.
* Applications.
* Theory of measurement.
-Shale-base line& Sand line
-SSP, PSP and SP log readings
* Factors affecting on log readings.

5. SP log “Definition”
The SP is a measure and record of direct current
(DC) voltage differences between the naturally
occurring potential of a moveable electrode in
the well bore, and the potential of a fixed
electrode located at the surface.
The SP log is recorded on the left hand track of
the log in track #1
It is measured in millivolts (mv).

8. SP log “General Uses”
The SP log is used to identify impermeable
zones such as shale, and permeable zones
such as sand,
Detect boundaries of permeable beds,
Determination formation water
resistivity(Rw),
Calculation the volume of shale in
permeable beds.

9. Theory of Measurement

10. SP log “Definition”
The SP is a measure and record of direct current
(DC) voltage differences between the naturally
occurring potential of a moveable electrode in
the well bore, and the potential of a fixed
electrode located at the surface.
The SP log is recorded on the left hand track of
the log in track #1
It is measured in millivolts (mv).

12. …THANKS ..