--> Abstract: Regional Mapping of Genetic Units in the Almond Formation, Greater Wamsutter Field, Southwest Wyoming: Phase II: What to Do Without a Flooding Surface: Mapping the Coastal Plain, by Tina L. Gammill, Austin J. Roelofs, Alan J. Scott, Natasha M. Rigg, Ben J. Kessel, Will D. Monn, and Mark L. Bacon; #90078 (2008)

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Regional Mapping of Genetic Units in the Almond Formation, Greater Wamsutter Field, Southwest Wyoming: Phase II: What to Do Without a Flooding Surface: Mapping the Coastal Plain

Tina L. Gammill1, Austin J. Roelofs1, Alan J. Scott1, Natasha M. Rigg2, Ben J. Kessel2, Will D. Monn2, and Mark L. Bacon1
1Anadarko Petroleum Corp, The Woodlands, TX
2Anadarko Petroleum Corp, Denver, CO

The Almond Formation is the primary production target in the greater Wamsutter area in the Washakie Basin. Phase I of this project used a triple-log "pseudoseismic" display to establish genetic intervals through correlation of major flooding surfaces in the middle, marine-influenced wedge of the Main Almond. The objective for Phase II was to correlate and map reservoir quality sands in the upper and lower Main Almond coastal plain/estuarine units where major flooding surfaces were lacking or absent. This extension adds potential reserves and improved commerciality of development wells.

Depositional styles differ between the lower and upper Main Almond units; the nature of this style determined our approach. The lower Main Almond consists of large, stacked channel complexes encapsulated within coastal plain coals and estuarine mudstones. Correlations were based on laterally extensive coals and the erosional bases of the channel complexes. The upper Main Almond consists of smaller estuarine/fluvial channels, inter-channel splays, and estuarine deposits. Minor flooding surfaces were used to correlate in the down-dip extent of the field; these were replaced up-dip by laterally-extensive coals.

Three lower Main Almond intervals with thick estuarine and fluvial channel sand complexes were mapped. Mapping of these bodies shows reciprocal sedimentation of these complexes through time. Additionally, eight coastal plain intervals were mapped in the upper Main Almond unit.

This approach has proven to be a cost-effective method to regionally evaluate reservoir potential and facilitate developmental planning in a predominantly coastal plain environment. The integrated set of nineteen Almond genetic intervals forms the basis for stochastic reservoir evaluation and aid effective field development decisions.

 

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas