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QUESTION: Asalaam oAalikum,
Dear Sir,
I am confused with the application of Carbolog for determination of TOC. Sir how to determine poles Om,water,matrix etx and how to apply them. kindly let me know its procedure step by step, I am unable to figure out from original Paper of Carbolog by Carpenter et al. Thanks a lot for your time.

ANSWER: I could not find the original paper on line and am not familiar with the log.  All I could find was this:

If you could send me a link if you have one, I will read it and see if I can determine the procedure.

---------- FOLLOW-UP ----------

Finally able to track down original paper after continuous struggle..

Just paste that link in your browser and wait for downloading sir. I will wait for your response.

I finally was able to download it.

Sonic logs response is based on the content of water, clay and organic material.  But it cannot differentiate the absolute relative amounts, it is only an indication of the total of the three.

The resistiviity log comes into use to separate the relative amounts of water and clay which are conductive.

Organic matter (and oil) are not.

For the measurement to work the method needs to be calibrated in a well in which Total Organic Carbon has been determined for the target interval or formation.

This can then be related to the log responses.

The authors say a rough description is:

An increase in the delta T in the sonic log combined with a decrease in the resistivity, corresponds to an increas in the water or clay content or visa versa.  An increas in delta T combined with an increase in resistivity corresponds to an increase in organic matter content OM.

The formula describe how to derive lots where by other wells can be classified using the calibrated logs.


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Keith Patton


I can answer questions concerning physical and historical geology, environmental geology/hydrology, environmental consulting, remote sensing/aerial photo interpretation, G&G computer applications, petroleum exploration, drilling, geochemistry, geochemical and microbiological prospecting, 3D reservoir modeling, computer mapping and drilling.I am not a geophysicist.


I have 24 years experience split between the petroleum and environmental industries. I have served as an expert witness in remote sensing, developmental geologist, exploration geologist, enviromental project manager, and subject matter expert in geology and geophysical software development.

American Association of Petroleum Geologists
American Association of Photogrammetrists and Remote Sensing

Bachelor and Master of Science
Registered Geologist in State of Texas

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