Publication History: This article is based on Chapter 7 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 Selecting LITHOLOGY Models
The quality of the answers for all lithology models will vary, and in some cases be unreasonable or impossible to calculate due to lack of data. In order of preference, we would choose:

Special case for gas zones
1. PE 2-Mineral Model
Uses PE log only. The PE has no gas effect so is the BEST and ONLY model for gas zones. Also good in oil or water zones. 

3-Mineral MODELS
DO NOT use in gas zones.

2. DENSma - Uma 3 - Mineral Model
Uses PE, Density, Neutron logs, BEST model in good borehole

3. Mlith - Plith 3-Mineral Model
Uses PE, Sonic, Neutron, may be OK in rough borehole.

4. Mlith - Nlith3-Mineral Model
Usws Sonic, Density, Neutron logs

5. Alith - Klith 3-Mineral Model
Uses Sonic, Density, Neutron logs

2-Mineral MODELS
6. PE 2-Mineral Model
Uses PE log only. The PE has no gas effect so is the BEST and ONLY model for gas zones. Also good in oil or water zones. 

DO NOT use the following in gas zones.

7. Uma 2-Mineral Model
Uses PE and Density logs

8. DENSma 2-Mineral Model
Uses Density log and PHIe from any porosity model.

9. DTCma 2-Mineral Model
Uses Sonicy log and PHIe from any porosity model.

10. Plith 2-Mineral Model
Uses PE and Density logs.

11. Mlith 2-Mineral Model
Uses Sonic and Density logs.

12. Nlith 2-Mineral Model
Uses Neutron and Density logs.

13. Alith 2-Mineral Model
Uses Neutron and Density logs.

14. Klith 2-Mineral Model
Uses Sonic and Density logs.

15.KUT Clay Typing Models
Uses Spectral Gamma Ray log.
 

MULTI-Mineral and statistical MODELS
Usually work when gas, if present, is treated as one of the minerals.
See links in menu at the right.
 

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