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Gamma Ray Shale Volume vs. Gamma Ray Index

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gamma-ray

Gamma Ray Clean must be less than Gamma Ray Shale.
Instructions

This crossplot displays shale volumes calculated from the gamma ray log. Linear and non-linear equations are presented.

Inputs are highlighted in yellow and  outputs are color coded, based on the equation used. Enter the average gamma ray log value over the interval of interest, as well as gamma ray log values for clean (no shale) and shale  (completely shale) intervals. The linear output is known as the gamma ray index, which is used as input to the non-linear equations.

Data points associated with output values are plotted on the cross plot for reference and are also color coded. 

 

References

Bush, Robert, E., and Mardock, E.S., "The Quantitative Application of Radioactivity Logs." Petroleum Transactions AIME, Volume 192, 1950: 191-198.

Bhuyan and Passey, "Clay Estimation from GR and Neutron-Density Porosity Logs." SPWLA, Thirty-Fifth Annual Logging Symposium, 1994, papper DDD.

Clavier, C.,  Hoyle, W., and Meunier, D.,  "Qunatitative Interpretation of Thermal Neutron Decay Time Logs: Part I Fundamentals and Techniques." Journal of Petroleum Technology Volume 23, Number  6, 1971: 743-755.

Heslop, A., "Gamma-ray Log Response of Shaly Sandstones." The Log Analyst Volume 15, Number 5, 1974: 16-24.

Katahara, K.W., "Gamm Ray Log Response In Shaly Sand." The Log Analyst Volume 36, Number 4, 1995: 50-55.

Larionov, V.V., "Borehole Radiometry." Book Published in Russian Language, Moscow, 1969.

Poupon, A., and Gaymard, R., "The Evaluation of Clay Content from Logs." The Log Analyst Volume 11, Number 6, November - December 1970: 18-25.

Stieber, S.J., "Pulsed Neutron Capture Log Evaluation: Louisiana Gulf Coast." American Institute of Mining, Metallurgical and Petroleum Engineers, 1970, SPE 2961.

Aptian Technical

 

Client Comments

“We are going to run with your model Dorian. I think your average perms over the intervals are in line with publications for the area. Great work on this set!”

B.L., Principal Geologist

“It’s nice to see your work around the office – always a solid place to start from.”

G.G., President & Principal Geoscientist

“Great work on the last round of data. I threw a few new technical tasks your way and you did a great job integrating them.”

B.L., Principal Geologist

“The merged compressional sonic log that you created now ties the seismic from surface to TD. Great job.”

N. K., Senior Geophysicist

“Thanks Dorian, this is why we keep coming back to you. Hassle free, no BS service, very refreshing.”

Z.J., Senior Geologist

“Many thanks Dorian, excellent work.”

J.C., Lead Geoscientist

“Thanks again Dorian.  And BTW, your analysis helped us enormously with our reserves evaluations. Your company does hold authority.”

P.T., Vice President Exploration

“Thanks Dorian, I knew you would come through. This is one of the reasons we keep coming back to you…you always deliver.”

Z.J., Vice President Exploration

“Hi Dorian, I was just going through the mapping and it looks great so far! Very happy with what I’m seeing.”

J.G., Senior Geologist

“Thanks Dorian for the quick turnaround. Your proposal for petrophysical services looks very good (impressive) and I will be approving.”

A.B., Vice President Geosciences

“Your petrophysical model matches core very closely.”

B.E., Senior Engineer

“Hi Dorian, Thanks for solving those problems. You have a black belt in petrophysics.”

S.R., Senior Geophysicist

“Excellent work! Thank you for the speed!!!”

R. R., Senior Engineer

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J.M., Vice President Exploration & Production

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R.C., Senior Engineer

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T.G., Geologist

“We took your advice and had some cuttings analyzed in a few wells. The results support your interpretation. Thanks for pointing us in the right direction.”

D.M., Senior Geophysicist

“We have found your petrophysical evaluations extremely useful and have had good success integrating the work into Petrel.”

A.B., Vice President Geosciences
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