Sequence Stratigraphic and Depostitional Facies Framework of the Lower Cretaceous McMurray
Formation, Kearl Oil Sands Project,
Nardin, Thomas1,
Joan Carter2, Bob Falls2, John Irish2, Stan
Stancliffe2, Bogdan Varban2,
The McMurray Formation in the
Regionally, the McMurray Formation is a
deepening-upward fluvial-estuarine complex deposited within a paleo-valley system controlled by the configuration of the
Sub-Cretaceous unconformity. The Kearl stratigraphic study was based on ~1000 wells (75% cored),
43 km of 2D seismic and integration with previous regional work. These data
show that the McMurray Formation is characterized by abrupt lithofacies
changes, inclined stratal geometries and high-relief
unconformities. This stratigraphic complexity can be
organized within a sequence framework. Four major sequences are recognized. The
oldest sequence (I) is dominated by thick amalgamated braided stream deposits
overlain by a shoaling-upward succession of lacustrine
muds, paleosols and coals.
Sequence II is a thick, heterolithic assemblage of
fluvial, floodplain, and estuarine deposits. Sequence III is distinguished by
large-scale fluvial-estuarine point bars that are up to 70 m thick and
represent the primary reservoirs at Kearl. Bayhead delta muds contained
within deeply incised valleys typify Sequence IV.
This study has resulted in an enhanced
understanding of McMurray depositional systems that is utilized for resource
characterization and assessment, reservoir modeling, pit design, drilling
programs, ore processing and substrate stability evaluations.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California