Tectono-Stratigraphic Framework of the Permo- Triassic Section in the Prudhoe Bay Area
By
C.E. Paris (BP Exploration (Alaska) Inc.)
A tectono-stratigraphic framework for the Permo-Triassic
Section in the Prudhoe Bay area was created to enhance reservoir modeling,
infill drilling, and exploration for the reservoirs
within this section. The
framework was created by incorporating all of the subsurface information
available between the Colville and Canning Rivers, including log data from over
2,000 wells, seven 3-D seismic surveys, and core information from over 100
wells.
The Permo-Triassic section in the Prudhoe Bay area
contains seven tectono-stratigraphic sequences. The initial transgressive
sequence is represented by the Echooka Formation and lower Kavik Shale. This
sequence documents the progressive drowning, from southwest to northeast, of the
Pre Upper Permian Unconformity, which incised into the underlying Lisburne Group
carbonate platform. The subcrop and the onlap pattern of the Pre Upper Permian
Unconformity indicate that a tectonic high (the Orion High) existed north of
Harrison Bay, and a second high (the Mikkelson High) existed northeast of the
Prudhoe Bay Unit, during Permo-Triassic time. These tectonic highs were the
source areas for the siliciclastic deposits of the upper Kavik Shale and Ivishak
Formation. The Kavik Shale and Ivishak Formation contain four deltaic
-fluvial
sequences and a forced regression sequence, which are strongly controlled by the
tectonic activity of these highs. This section is capped by a widespread early
rift/extensional sequence represented by the Shublik and Sag River Formations.
AAPG Search and Discovery Article #90008©2002 AAPG Pacific Section/SPE Western Region Joint Conference of Geoscientists and Petroleum Engineers, Anchorage, Alaska, May 18–23, 2002.