Publication History: This article is based on Chapter 6 of "The Log Analysis Handbook" by E. R. Crain, P.Eng., published by Pennwell Books 1986  Updated 2004, 2021. This webpage version is the copyrighted intellectual property of the author.

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Crain's Usage Rules For Permeability MethoDS
The methods shown on other pages of this Handbook provide numerous independent approaches for calculating permeability, as well as a number of correction factors which could be applied.  If no reconciliation can be made between alternative models, discard the least trustworthy results. In order of preference, it is suggested you use:

BEST METHODS
1. Permeability from Porosity Model
Use in sands, shaly sands, carbonates when permeability regression versus porosity is good to excellent. Results automatically calibrated to core.

2. Permeability from Porosity and Water Saturation - Wyllie-Rose and Timur Models
Use in sands, shaly sands, carbonates. Adjust parameters to obtain match to core.
 

3. Permeability from Porosity and Water Saturation - Lucia Model
Best model for carbonates. Adjust parameters to obtain match to core.
 

Other METHODS
 

4. Permeability from Porosity - Domanoir and Coatwa Models
Use in sands, shaly sands only. Adjust parameters to obtain match to core.
 

5. Permeability from Stonley Wave Model
Rarely used due to lack of data.
 

Special Cases
6. Fracture Permeability

Requires fracture aperture data from resistivity image log.

TRIMming Permeability RESULTS
Porosity and water saturation must be trimmed before use in permeability equations.

Trims may be needed to remove results above 2000 mD before display or use in other calculations, for example:
      1: PERMw = Min(2000, PERMw)

Fracture permeability may exceed 50,000 mD but such high values should be confirmed by pressure transient analysis.
 

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