Integrated
seismic
and geologic
analysis
of high density fracture zones within the Niobrara Formation in Moffat County, NW Colorado
Vivian Lin, J. Frederick Sarg, and Stephen Sonnenberg
The Niobrara Formation is a self-sourced resource play with key production occurring in 'sweet spots' that may extend downdip off structure, unlike in conventional reservoirs. Mapping the location and orientations of high density fracture zones is key to identifying these productive areas in tight petroleum systems. This study integrates a 3D
seismic
interpretation with a well log
analysis
in order to determine how high density fracture zones in the Niobrara relate to
facies
distribution and regional structures (particularly from the Laramide compressional and Neogene extensional tectonics). Maps of high density fracture zones were produced from
seismic
attribute
analysis
including dip azimuth and curvature. The high density fracture zone maps were then compared to local structures to determine whether regional tectonics could account for the location and orientations of all or a subset of the high density fracture zones. The fracture zone maps were also compared to
facies
distribution maps, which were produced from sequence stratigraphic
analysis
of
seismic
and well log data. The results of this study conclude that tectonics,
facies
, brittleness, and current stress regimes all contribute to the location, orientations, and density of the fracture zones within the Niobrara. It is suspected that other processes (such as hydrocarbon generation and the solution of evaporites) also play a role in fracture development. This integrated approach using
seismic
and well log analyses can be applied to explore other trends within the Sand Wash basin and nearby regions. The relationships identified in this study between
facies
, brittleness, current stress regimes and regional structure allow for better identification and prediction of 'sweet spots'. In areas where good
seismic
and well log data are available, the same procedures conducted in this study may be applied to produce high density fracture zone, structural, and
facies
maps that may then be analyzed to determine the most prospective locations. Even in areas where
seismic
and well log data may be limited, these relationships permit exploration play trends to be high-graded for further data acquisition and analyses.
AAPG Search and Discovery Article #90156©2012 AAPG Rocky Mountain Section Meeting, Grand Junction, Colorado, 9-12 September 2012