--> ABSTRACT: Organic Petrography--An Old Dog with New Tricks for Petroleum Geochemistry, by Joseph T. Senftle; #91038 (2010)

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Organic Petrography--An Old Dog with New Tricks for Petroleum Geochemistry

Joseph T. Senftle

Some published applications of organic petrography to petroleum geochemistry have met with limited success in the past. It appears that poor consistency of data and lack of an appropriate terminology have been major causes for this limited success. It is now evident that detailed organic petrographic analysis of organic matter requires multimode illumination microscopic methods using transmitted and reflected white light illumination along with incident ultraviolet light excitation-induced fluorescence. This petrographic approach permits the distinction of relatively hydrogen-rich from hydrogen-poor kerogen.

It is well known that organic matter in most rocks consists of a complex, diverse mixture of organic constituents, each derived from different plant and animal precursor materials which have undergone chemical change related to depositional environment, diagenetic history, and thermal maturation. Bulk and detailed characterization of soluble and insoluble organic matter in rocks, without an understanding of the organic constituents present, in addition to the mode of occurrence and alteration of the material can lead to an extremely limited and sometimes erroneous evaluation of the data. This, in turn, can lead to an improper evaluation of the thermal maturity and source rock potential of the sedimentary section.

Detailed organic petrographic analyses of organic matter both in concentrated kerogen preparations and in whole rock mounts have been performed in conjunction with geochemical analyses including elemental analysis, Rock-Eval, pyrolysis-gas chromatography, and solvent extraction/gas chromatography. This integrated approach has been applied to potential source rock sections of oil-bearing basins and frontier basins, both leading to an improved understanding of the geology and petroleum producing potential of these areas.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.