Spontaneous Potential Log

S ont ontaneo aneous us Potential Lo s

Courtesy: Wikipedia

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Bassiouni Ch. 6 Spontaneous Potential Logs

indicator and secondarily as a fluid salinity indicator.

Two Diffusion Mechanisms

Comparison of  Sands and Shales for Muds “Fresher” an orma on

Com are this res onse to a natural gamma ray log

~Normal device with no source (A, B missing)

N

M

The actual deflection depends on fluid salinity

Mud is saltier than formation

Formation is saltier than mud

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Know the acron ms for the lo s, e. ., CNL Think of the physics:  –   –   – 

What is the log actually measuring? What formation property are we approximating? What corrections are likely to be needed?

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can be constructed in many ways. Com are numerous lo s if available  –   – 

Are they consistent? What do the discrepancies mean?