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Geochemical Study of Oils, Source Rocks, and Tar Sands in Pauls Valley Area, Anadarko Basin, Oklahoma

P. J. Jones, C. A. Lewis, R. P. Philp, L. H. Lin, G. E. Michael

An organic geochemical study of numerous oils and source rocks from the Anadarko basin has been undertaken in an attempt to determine the number of genetically related families of oils in the Pauls Valley area of the Anadarko basin, in addition to determining the potential source rocks for these oils. In the study area it was found that, of the oils examined, there were basically two families of oils. The majority of oils examined from the Oil Creek, Bromide, Hunton, and other sands appeared to have a similar source which appeared to be the Woodford Shale. A smaller and distinct group of oils appeared to be source and reservoired in the Viola Limestone. The correlations were made by determination of the various classes of biomarkers in the oils and source rock extract. Th compounds examined included n-alkanes, isoprenoids, steranes, hopanes, and monoaromatic steroid hydrocarbons. The distributions of these compounds will be discussed in addition to the way in which the data are used to make the above-mentioned correlations.

In the course of this study, a number of tar-sand samples in Upper Mississippian tar sands from Carter County, Oklahoma, were also examined in some detail. These samples were of particular interest since they presented an opportunity to study samples that had been biodegraded to differing degrees. Hence several classes of biomarkers, namely alkanes, steranes, hopanes, mono and tri-aromatic steranes, and porphyrins, were analyzed from these different tar sands. The aims of the study were two-fold, with the first being to study the in-situ effects of progressive biodegradation on a series of samples derived from the same source. The second was to determine the origin of the oil responsible for the tar sands. Results will be presented to show progressive changes in the biomarker distribu ions resulting from biodegradation, such as selective removal of certain stereoisomers and ring cleavage within the steranes. In addition, the attempted correlation of the tar-sand oils with the Oil Creek oil will be discussed and data presented to demonstrate that in all probability this oil is indeed responsible for these particular tar sands.

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