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Hello,
I need your help. I have to calculate porosity in shale (potencially gas/oil shale). I have sonic log, GR, laterolog and neutron log (this one is not calibrated into porosity units, but is in counts/min). All logs are old fashioned Soviet logs only on sheetpapers. Now question: can I freely apply GR to calculate Vsh in shale; and can I apply Willy equation for calculating porosity in shale? Will it be correct? I have many doubts, that's why I ask for help. All calculation have to be done with no software.

.Unless you don't have calibration of Neutron tool, you can't covert counts into porosity measured. I mean how we know how much counts corresponds to how much porosity. There should be calibration or something mentioned in the log somewhere.
Please let me know if there is anyway to covert counts into porosity without having calibration.

Thanks for reply. I have found out that it's possible. See: http://www.spec2000.net/17-specancient.htm
However, I do not know how much I can trust it.

Good to know...Just be sure about constraints and correct chart when you use this method.


cheers..

I extremely do not suggest to use sonic logs for porosity evaluation in gas reservoirs, because of gas impact.
The best supply of porosity information in gas shale is, of course, density tool.

Can anybody help me understand CT scanning and how it can help in Shale porosity calculation?