A New and Practical Approach to
Mud Log Evaluation and Interpretation
Mud Logging is a capricious science and service that has been utilizing similar methodologies for over 50 years. In the course of logging 2,000 wells in 6 years and using conventional Mud Logging techniques, I made an analytical advance in mud logging by developing an empirical formula to evaluate productivity of a reservoir based on the Total Gas recovered from the reservoir. Total gas or "hot wire" is available in all mud logs including very old mud logs. Not only is it useful for new logs on the fly but with some comparative information, this approach can be used for evaluating old mud logs also.
The purpose and benefit is to reduce human subjectivity and increase scientific value and repeatability. It is useful for old conventional plays or evaluating a new unconventional resource play. It is another technique or tool that can be very enlightening.
The core of the interpretation is based on qualitatively solving for Sw in the OOIP formula. As a result, the product is frequently interchangeable with Sw calculated from open hole logs.
How it works
In Open Hole Log Interpretation, subject to lithology and water salinity (Rw), you are essentially normalizing Resistivity to Porosity. You are asking, do I have enough resistivity for this porosity to be productive.
In mud logging, we all know "gas" can indicate oil. The question is, how much "gas" does it take to be oil productive? The fundamentals of interpretation are intuitive and as follows:
- More Oil yields More Total Gas
- A Higher GOR Reservoir yields more Total Gas
- A thicker Drilling Fluid Yields less Gas
The combination of the above in conjunction with understanding the variables of porosity and permeability can greatly aid in the use of mud logs in estimating productivity of a reservoir. This information is not intended to replace open hole logs but rather as an aid to you in understanding what the mud log is actually telling you.
The Product
For $125 you get access to the following:
- An online calculator for estimating productivity given in terms of Sw from your mud log data.
- A written manual to aid in the understanding of the formula and its interpretation including evaluating old mud logs.
For Mud Log Evaluation Consulting Services or other geological services please email directly: info@mudlogevaluation.com
“I received the document in seconds! You have transformed simple data (GOR) in a new and very original exploration concept and production tool.
Now, the mudlogging has much more value.”
— Roberto J. Garcia
Exploration & Production Manager
Buenos Aires
Download the Advanced Mud Log Evaluation Manual Here and Receive Password to Calculators
Click the Add to Cart button below to download this 14 page Advanced Mud Logging document that:
- Explains my water saturation calculation derived from mud logs
- Gives Examples of Mud Log Evaluations for new wells
- Gives an interpretation method for old mud logs
- Discusses using mud logs as an aid to releasing differentially stuck drill pipe
- A synopsis of mud log management and evaluation best practices
Additional Information
For more information please email Bud Johnson: info@mudlogevaluation.com
© 2023 R.S. Bud Johnson |