Paleozoic Source Rocks in the Central Utah Thrust Belt: Organic Facies Response to Tectonic and Paleoclimatic Variables
Wavrek, D. A.1, J. Ali-Adeeb1, J. C. Chao1, L. E. Santon1, E. A.
Hardwick1, D. K. Strickland2, and D. D. Schelling3
1Petroleum
Systems International, Inc, Salt Lake City, UT
2Wolverine Gas
and Oil, Corp
3Structural Geology International, LLC
It was not long ago that the industry paradigm explained
exploration failure in Central Utah due to inadequate source rock. Our
recent studies, however, have proven the existence of hundreds of feet
of Mississippian and Devonian source rock. Detailed examination of
nearly 600 potential source rocks from the Permian-Devonian
stratigraphic horizons in Central Utah reveal important points:
1. measured TOC in the Mississippian-Devonian horizons
exceeding 2% are found in Black Canyon 1, WXC-Barton 1, Sunset
Canyon Unit 1, Desolation Unit 1, Bishop Springs Unit 1, Antimony
Canyon 1, Paxton 1, Thousand Lakes Mountain 2, Fishlake #1-1, and
Tanner 1-27; 2. all Pennsylvanian horizons are below the 2%
threshold, except for the Manning Canyon Formation; 3. all Permian
horizons with TOC exceeding 2% (Moroni 1-A, Salina Unit 1, and
Paxton 1) are interpreted to be stained with migrated hydrocarbons
(i.e., not indigenous organic matter); and 4. outcrop sample data
reinforce conclusions from the subsurface dataset.
Understanding organic facies require the integration of tectonic
and paleoclimatic variables. For example, the western margin of the
Chainman Basin has influence from sediment influx from the Antler
Orogeny (i.e., dysoxic facies; maximum TOC 6%) whereas the
central area is an anoxic sediment starved depositional system
(maximum TOC 16%). In contrast, the eastern margin is influenced
by upwelling and contains phosphorites (i.e., upwelling facies;
maximum TOC 4%). The practical significance of this latter point is
that the upwelling will impart a distinct molecular signature that can
lead to erroneous source rock correlations (e.g., Permian Phosphoria
Formation). Palinspastic reconstructions are used to better define the
distribution of source rock, organic facies, and stratigraphic
correlations in the study area.
AAPG Search and Discovery Article #90071 © 2007 AAPG Rocky Mountain Meeting, Snowbird, Utah