--> Abstract: Stratigraphic Architecture of Two Incised Valley Fills: Fiddler Creek and Clareton Fields, Wyoming; #90063 (2007)

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Stratigraphic Architecture of Two Incised Valley Fills: Fiddler Creek and Clareton Fields, Wyoming

 

Pederson, Keriann H.1, David W. Bowen1 (1) Montana State University, Bozeman, MT

 

Fiddler Creek and Clareton incised valley-fill trends, in the Powder River Basin, Wyoming, constitute a rare geologic setting. This study compares and evaluates the stratigraphic architecture of the two adjacent Early Cretaceous paleovalley-fills. Stratigraphic architecture controls the three-dimensional relationships of porosity and permeability and thus potential migration and leakage pathways of both natural and induced fluids. In turn, fluid migration pathways determine suitability of these systems for Enhanced Oil Recovery (EOR) and carbon dioxide sequestration.

 

Stratigraphic architecture is a function of accommodation and sediment supply. Seldom are any sedimentary controls constant thus allowing the other to be evaluated independently. The two paleovalley systems that are the focus of this study are exceptional in that they have common controls on accommodation, are proximal, and similar in relative size. They differ in that Fiddler Creek valley system is a coastal plain valley with limited sediment supply, whereas Clareton valley system is a piedmont valley with high sediment supply. This allows the effects of different sediment supply rates to be evaluated independently.

 

Data in the study area consists of surface outcrops, greater than 6,000 wireline logs, and numerous cores. This data facilitates continuous mapping of the valley systems 75 kilometers down the valley axes. Multiple bentonite layers are also present in each of the valleys; dating of these bentonites and their correlation between the valley-fills aids in interpreting internal valley stratigraphy and helps to establish subsidence rates for each valley-fill.

 

Because of their similar history and the plethora of data available for these two unique valley-fill systems, they are ideal for studying the sediment supply control on stratigraphic architecture in incised valleys.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California