Beyond Porosity: Lithology from Logs - Dan Krygowski - Oklahoma City

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Oklahoma City

Oklahoma City, OK

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The course assumes a basic understanding of common openhole logging measurements and interpretation, and uses that working knowledge to expand the interpretation of “porosity” and other measurements to the determination of lithology. Exercises provide the means to put the information shared here into practice.

The course:

• Offers a “hands-on” approach to the prediction of lithology from openhole measurements;

• Focuses on the interpretation of lithology, including shale volumes and complex lithologic mixtures;

• Introduces a variety of interpretation techniques in the context of the availability of newer, more extensive, data;

• Starts with simpler interpretations and moves to more complex interpretations using newer measurements.

The course strives to build on the existing understanding of petrophysical interpretation techniques to recognize common lithologies at a glance, improve lithologic interpretations with a minimum of effort, and provide some understanding of what petrophysical software does “under the hood.”

Course topics include:

• A quick review of the physics of the measurements to be discussed;

• Determination of the volume of shale or clay. The schools of thought and the terminology;

• Determination of lithology and better estimates of porosity through crossplots and QuickLook techniques;

• Determination of more complex lithology through M-N Plots and MID Plots;

• The issues involved in the determination of lithology from elemental spectroscopy.

Equipment needed: Calculator with exponent functions, straight-edge, pencil or pen.


  • Course Logistics, Introduction

  • Physics of the measurements

  • Gamma ray, SP

  • Sonic traveltime, bulk density and photoelectric effect, neutron porosity

  • Determining the volume of clay or shale in the formation

  • Schools of thought; needed data; tradeoffs

  • Using gamma ray, SP, neutron porosity and bulk density

  • Discovering lithology and porosity

  • Crossplots: lithology pairs and porosity

  • QuickLook methods

  • Mineral triads:

  • M-N Plots and MID Plots

  • Lithology from elemental spectroscopy

  • Wrap-up


Dan Krygowski is a Senior Petrophysical Advisor with The Discovery Group, which he joined in late 2006. He has over 35 years of experience in the art and science of petrophysics, and in the development and design of petrophysical software. Dan earned a B.A. in Physics from the State University of New York at Geneseo. After earning M.S. and Ph.D. degrees in geophysics from the Colorado School of Mines (with a focus on petrophysics), he joined Cities Service Company, and worked in Denver and Tulsa. After Citco, he joined Atlantic Richfield Company (ARCO). In both companies he gained experience in a variety of geologic and geographic areas in both technical and management positions in petrophysics.

After ARCO, he joined Landmark Graphics, and was a member of the PetroWorks development team as the team’s petrophysical Subject Matter Expert. He was also involved in interface design, and development of documentation and training materials. When Landmark closed its Austin, Texas office, Dan joined Chevron, working in deep Gulf of Mexico and Chad, Africa projects. He also supported internal petrophysical training efforts.

Since the late Cretaceous, Dan has taught the AAPG Basic Well Log Analysis course annually with Dr. George Asquith of Texas Tech University, and for the last several years, with the addition of Rick Lewis, of Schlumberger. Dan also teaches Basic Openhole Log Interpretation, a similar, but shorter course, and Petrophysics Elements, a much longer, lower intensity course meant to delve deeper into petrophysical information and methods as part of participants’ regular job duties. Both are taught through direct client requests. Dan and other Discovery Group members present other petrophysical courses as well.

In 2004, AAPG published George and Dan’s book, Basic Well Log Analysis, a second edition of George’s 1983 similarly-named book which was one of the AAPG’s all-time best selling publications. The 2004 edition has also become an AAPG best-seller.

Dan is a member of the Society of Petrophysicists and Well Log Analysts (SPWLA), American Association of Petroleum Geologists (AAPG), Society of Petroleum Engineers (SPE), Society of Exploration Geophysicists (SEG), the Denver Well Logging Society (DWLS), and the Rocky Mountain Association of Geologists (RMAG).

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Oklahoma City, OK

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