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Reconstruction of Paleoenvironments through Integrative Sedimentology and Ichnology of the Pennsylvanian Strawn Formation in the Katz Field, North-central Texas

Jesse G. White1, Peter P. Flaig2, Stephen T. Hasiotis3, and D. Jeffrey Over4

1Kinder Morgan CO2 Company, L.P.
2Bureau of Economic Geology, University of Texas at Austin
3University of Kansas
4Geneseo State University of New York


Kinder Morgan's Katz Oil Field miscible CO2 flood (Katz Strawn Unit; KSU) is located on the Eastern Shelf of the Permian Basin and covers portions of northeastern Stonewall, King, Knox, and Haskell counties of north-central Texas. Four cores from the Pennsylvanian Strawn Formation in the Katz field were logged with particular attention given to identifying lithofacies and ichnofacies. A combination of core observations and well log data were used to reconstruct paleoenvironments to clarify probable sandbody geometries, shale continuity, and spatial and temporal trends in porosity and permeability.

All cores contain facies and trace fossil assemblages typical of a mixed siliciclastic-carbonate continental-to-shelfal transitional succession found along a complex embayed coastline. Six petrophysically distinct lithofacies were identified: 1) lenticular to wavy-bedded mudstone, 2) flaser to wavy-bedded sandstone, 3) carbonate-rich sandstone, 4) ripple-to trough cross-laminated sandstone with common convolute bedding, 5) trough cross-laminated sandstone with abundant mud rip ups and mud balls, and 6) heavily bioturbated sandstone. Trace fossils include, Asterosoma, Diplocraterion, Chondrites, Conichnus, Cosmorhaphe, Cylindrichnus, Helminthopsis, Phycosiphon, Rhizocorallium, Rosellia, Skolithos, Teichichnus, and Zoophycus, indicating a combination of Skolithos, Cruziana, mixed Skolithos-Cruziana, and rare Zoophycus ichnofacies. Combined lithofacies and ichnofacies observations suggest that paleoenvironments of the Katz field included a bayhead delta, back-barrier estuary-embayment, flood tidal delta, tidal flat, and upper to middle shoreface. Conodonts collected from a crinoid-bryozoan-brachiopod wackestone-packstone in two of the cores include age-diagnostic species (Neognathodus expansus and Gondolella pohi, Idiognathodus aff. I delicates) indicating a mid Desmoinesian with CAI values of 1 to 1.5.


AAPG Datapages/Search and Discovery Article #90190©AAPG Southwest Section Annual Convention, Midland, Texas, May 11-14, 2014