Numerical Earth Models* (NEM) is a good blend of discussion and math, and, although we didn’t understand much of the latter, the subtext turns out to be bang on in terms of the actualité of commercial earth modeling. Indeed, Prof. Mallet, recently retired from his position at the Nancy, France, School of Mines and father of GoCad, has performed a remarkable feat in slipping in a compelling piece of marketing for Paradigm’s new ‘Skua’ technology under the guise of an EAGE ‘Education Tour Series’ publication.
Mallet takes it as a given that earth modeling is the basis of E&P decision making. He dismisses the ‘classical,’ i.e. engineering CAD approach as being inadequate for modeling geological complexity and presents his ‘discrete smooth interpolation’ approach as used in GoCad. NEM includes some pretty good illustrations of complex geologies to back up the mathematical exposé. The math is tough, but accompanied by copious and relatively clear explanations for the mathematically challenged.
Mallet moves on from topological models to geostatistics, offering many examples of stochastically generated channels and geobodies. A chapter on seismic interpretation is a little idiosyncratic as it appears to dismiss conventional Fourier approaches to propose ‘trigonometric polynomial’ modeling of the seismic trace.
But the payload of NEM is in combining all of the above in the shared earth model and its successors, blending seismically derived attributes with the geometrical model. Mallet makes a good case for the inadequacy of ‘conventional’ pillar grid approaches of Schlumberger’s Petrel and many other tools including previous incarnations of GoCad.
Mallet’s answer is the ‘unified earth model,’ an approach that removes structural influences before performing cellularization and attribute modeling. A final chapter extends all of the above to upscaling and fluid flow modeling.
NEM is an extraordinary publication that conveys Mallet’s enthusiasm for modeling the earth, seismics, fluid flow and just about everything else. Is it ‘commercial?’ Definitely, and the EAGE is to be congratulated for producing a great blend of product-oriented discussion and science.
* EAGE 2008/ISBN 978-90-73781-63-4 and www.oilit.com/links/0807_9
This article originally appeared in Oil IT Journal 2008 Issue # 7.
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