Quick Look Techniques

QUICK LOOK TECHNIQUES (QLT’S) – THE RAPID MEANS OF VALIDATING INTERPRETATIONS, PROSPECTS, AND RESOURCE OR RESERVES ESTIMATES!!!

WE FAR TOO OFTEN HEAR THESE IMMORTAL WORDS:
“The Trap Was Not Present, Objectives Were Shaled Out, There Was No Seal, Fault Was Too Late, Seismic Velocity Problems Were Not Recognized, Objectives Were Wet, Sand Was Too Thin, or the Interpretation Was Incorrect.”

WHAT ARE QUICK LOOK TECHNIQUES (QLT’S)?
QLT’s are a collection of techniques that provide a rapid means of evaluating interpretations, prospects, and maps, and can be used to quickly evaluate resource and reserves estimates.

THE APPLICATION OF PROVEN METHODS AND TECHNIQUES!
QLT’s are based on the understanding of the technical methods required to do solid, geoscience and engineering exploration and production work. It tests the work against a model: “retro-geoscience or retro-engineering.”

TESTING THE COMPLETED WORK!
How can you test or validate an interpretation, map, reserves or resource estimates or a prospect in a limited amount of time? Before committing tens of millions of dollars, how do we determine if the subsurface picture is three-dimensionally valid “geologically and geometrically and if the resource or reserves estimates are reasonable?” We can do this by the application of Quick Look Techniques!

THERE ARE A VARIETY OF QLT’S. THEY INCLUDE:

• General Structural QLT’S
• Fault Surface QLT’s
• Faulted Structure QLT’s
• Seismic interpretation QLT’s
• Structural Geology QLT’s
• Directional Well QLT’s
• Engineering QLT’s
• Net Pay Isochore QLT’s
• Computer Mapping QLT’s
• Other QLT’s

GENERAL GEOSCIENCE-BASED ERRORS IN INTERPRETATION, PROPECTS, AND RESOURCE AND RESERVES ESTIMATING.
KEY AREAS FOR THE APPLICATION OF QLT’S INCLUDE:

• STRUCTURE MAPS
  • Too optimistic/unrealistic or even three dimensionally impossible
  • Mechanically correct but geologically wrong
  • Not based on sound data
  • Fault interpretation/integration incorrect
  • Incorrect use of structure vs. porosity tops and bases
• NET SAND/ NET PAY
  • Incorrect use of cutoffs (e.g. porosity)
  • Wrong application of correction factors for deviated wells/dipping beds
  • Incorrect application of net-to-gross ratios
• NET PAY (ISOCHORE) MAPS
  • Use of incorrect methods for construction of:
    • Bottom/Edge water net pay isochore maps
  • ◦Incorrect use of thicknesses (net sand/net pay)
  • Incorrect application of net-to-gross ratio
  • Incorrect application of wedges (water, hydrocarbon, fault

 ***The Quick Look Techniques and detailed interpretation and mapping principles are valid for both hand drawn and computer generated maps.

The textbook (1st edition) on QLT’s was published in 1994. The 2nd edition is currently under preparation and should be available in early 2007. This 2nd edition will include expanded examples of QLT’s, as well as two (2) chapters on computer mapping QLT’s. SCA offers training courses on QLT’s. In addition, we apply these methods to our consultancy services, especially in prospect evaluation.

In this section of our website, we present some examples of Quick Look Techniques for your information and review. The QLT’s presented here were published as a 10 part series in the Houston Geological Society Bulletin a few years ago.