Another Look at Hartzog Draw Stratigraphy, Powder River Basin, WY
Painter, Clayton S. and Randi S. Martinsen
University of
Wyoming, Laramie, WY
Hartzog Draw, a large oil and gas field, within the Powder River
Basin, Wyoming, produces from the Campanian Shannon Sandstone.
The Shannon has been the focus of numerous papers and much oral
debate, yet there is little consensus regarding its origin and
depositional setting. Furthermore, the current operator within Hartzog
Draw has encountered difficulties with water flooding the Shannon.
Although the water floods appear successful at first, before too long
the reservoir abruptly ceases to accept further flooding, and this could
indicate a lack of understanding of the Shannon Sandstone's
stratigraphy in Hartzog Draw.
A new data set of over 50 cores from Hartzog Draw has been
made available and it allows us to closer examine the reservoir's
stratigraphy and its possible subtleties that could be causing
unsuccessful water flooding. We performed detailed descriptions of
these cores, created cross sections across the length and width of the
Hartzog Draw and studied samples of the Shannon Sandstone in thin
section. Throughout the study particular attention was paid to possible
attributes that could cause a cessation of water intake such as barriers
causing compartmentalization and the presence of expansive clays.
We believe that these descriptions could help current oil and gas
producers to better understand the nature of the reservoir's
architecture and overcome current complications. In addition to
helping overcome present production complications, we believe that
our new insight into the detailed stratigraphy of the Shannon
Sandstone can be applied to better understanding the long-debated
history of its deposition and preservation.
AAPG Search and Discovery Article #90071 © 2007 AAPG Rocky Mountain Meeting, Snowbird, Utah