--> ABSTRACT: Application of Geochemical Wireline Logs to Lithological Interpretation, Reservoir Description, and Formation Evaluation, by S. L. Herron and M. M. Herron; #91021 (2010)

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Application of Geochemical Wireline Logs to Lithological Interpretation, Reservoir Description, and Formation Evaluation

HERRON, SUSAN L. and HERRON, MICHAEL M.

Recent developments in open and cased hole logging have made it possible to obtain accurate concentration logs for the elements silicon, calcium, iron, sulfur, titanium, and gadolinium at relatively low cost and high logging speeds. To complement these developments, a new interpretation was developed to quantitatively asses the lithological fractions of clay, carbonate, anhydrite, and quartz-feldspar-mica in the formation using only the elements Si, Ca, Fe, and S. This new interpretation is founded on an extensive data base comprising chemical and mineralogical analyses of over 400 core samples taken from fifteen wells throughout the world.

The elemental concentration logs, or the lithological interpretation derived from them, provide an extremely complete formation description for stratigraphic correlation. Whereas logs such as gamma ray can be correlated only on the basis of shape similarity, the elemental and lithology logs rely on both shape similarity and absolute value. When the absolute value changes laterally across a field it clearly reflects a lithological change as well.

The geochemical logs also provide a means of determining other matrix properties which are valuable for formation evaluation. Examples are matrix density and matrix hydrogen content, which can be used to greatly enhance the computation of total porosity from density and neutron logs.

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.