Using Core, Log and Seismic Data to Resolve the Cretaceous Units of the Powder River Basin

Abstract

Abstract

Whilst we continue to develop and enhance technologies to allow us to produce hydrocarbons from challenging unconventional resource plays, an equally important effort is required to improve the resolution of these plays, such that we can understand and predict key play components.

The application of a multi-disciplinary workflow is paramount to increasing this resolution and through the combination of core, cuttings, wireline log and seismic data across a basin, new geomodels and play components can be developed that help to reduce geologic and economic uncertainty.

An integrated geoscience project was commissioned to study the reservoir quality and stratigraphy of the Frontier to Dakota interval of the Powder River Basin. The interval contains a number of plays varying from classic marine tidal sandstone sheets through to lagoonal deposits of finite lateral and stratigraphic extent. The prospectivity of these plays is highly variable and a key controlling factor on successful exploration in the basin is to be able to resolve, map and correlate the most prospective units across the basin.

Here, we analyze 40 selected wells across the basin and conduct classic core description, thin section and palynological analysis to characterize their facies assemblages. These interpretations have been extended from initial core based studies to the full study interval through calibration to available cuttings data, wireline log suites and associated petrophysical derivatives. Ultimately, the interpretations were further enhanced by calibration with elastic properties derived from pre-stack inversion of the seismic data and the rock-based automated mineralogical analyses. With the seismic and well data acting as control, the interpretation was extended across the basin, allowing us to map the extent and character of the key Formations as a means of assessing exploration risk and new opportunities in this stacked interval.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016