Tying Rock Properties from Core to
Seismic
Reflectivity in the Kaiparowits Plateau, Utah
Abstract
Near-shore and shallow marine depositional systems are becoming increasingly important to understand due to the global hydrocarbon reserves held in such deposits. As resolution of seismic
reflectivity profiles increases, concepts of sequence stratigraphy can be utilized on the high resolution
seismic
datasets to improve the interpretation of
seismic
in near-shore marine successions. The Cretaceous John Henry Member (JHM), located in the Kaiparowits Plateau of southern Utah, reveals excellent exposures of fluvial and tidally influenced shallow marine deposits and offers an excellent opportunity to improve our understanding of imaging similar subsurface petroleum reservoirs. Previous work in this area has been focused on outcrops along the edge of the plateau, including 24 scattered cores. In this study we link a newly acquired
seismic
line to laboratory derived rock properties from a 440 m core that is approximately 50 m from the primary
seismic
line. The goal of this study was to use these rock properties from core combined with forward
modeling
to improve interpretation of
seismic
reflection data in shallow and near-shore marine deposits. The resulting line was subsequently tied to nearby outcrop descriptions to facilitate further understanding of the JHM. In order to accurately correlate rock properties to
seismic
, 60 core plugs and 15 thin sections were extracted to represent the 12 lithofacies exhibited in the core (EP-25). Core bench-top measurements were conducted to obtain Vp, Vs, density, permeability and porosity. The rock properties and corresponding thin sections illuminate the impact of grain size, sorting, mineralogy and clay content on
seismic
reflection within similar environments of deposition. Two intersecting
seismic
surveys (7 km in the north-south direction and 2 km in the east-west) were acquired on the plateau using 40 Hz frequency; this produced high resolution
seismic
data to which the forward models were calibrated, and provided a template for detailed interpretation of the
seismic
line. The wide range of Vp values (1500-4000 m/s) in a highly heterolithic system, and the number of overlapping values elucidates the complications of interpreting these deposits in
seismic
profiles. Integrating core,
seismic
and outcrop data improves multi-scale synthesis of data, and contributes to a better understanding of how to interpret fluvial and shallow marine deposits by placing them within a regional stratigraphic framework.
AAPG Datapages/Search and Discovery Article #90189 © 2014 AAPG Annual Convention and Exhibition, Houston, Texas, USA, April 6–9, 2014