--> Abstract: Hierarchical Stratigraphy and Channel Architecture of a Slope Valley Complex Set (Mariner Field, North Sea); #90063 (2007)

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Hierarchical Stratigraphy and Channel Architecture of a Slope Valley Complex Set (Mariner Field, North Sea)

 

Stelting, Charles E.1, Morgan D. Sullivan1, Graeme Bennet2 (1) Chevron Energy Technology Company, Houston, TX (2) Helix RDS, Aberdeen, United Kingdom

 

Hierarchical stratigraphic concepts and methods were employed to assess the reservoir character of Maureen and Lista formations in the Mariner Field (North Sea). The Paleocene reservoir sandstones of the Mariner Field were deposited in slope conduits extending from the East Shetland Platform into the deep-water Witchground Graben. Integration of seismic and well log stratigraphy reveals that the reservoir bodies were deposited in two distinct channel complexes within a slope valley system. These complexes are further sub-divided by well-log motifs into individual elements which vary in fill and architectural style: channel axis, channel off-axis, channel margin, levee/overbank, abandonment shale, and mass-transport deposits.

 

The channel complexes vary in type, architecture and net-to-gross reflecting temporal changes in sediment volume during the infill of the conduit. The Maureen Formation and Lower Heimdal Sandstone comprise the lower sequence and are composed of sand-rich, amalgamated channel-fill elements. The channel elements extend across the width of the slope valley and are overlain by a shale-dominated abandonment facies. Active sand deposition was reactivated at the onset of Middle Heimdal resulting in sinuous, semi-amalgamated channel-fill elements which cross-cut each other producing a well-connected, channelized reservoir interval. As sediment input into the slope valley began to wane, small, non-amalgamated, isolated channels accumulated in an otherwise mud-rich abandonment fill. The stratigraphic architecture of the Mariner slope valley complex is similar to other slope valley successions described from subsurface and outcrop examples.

 

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