PRB Tops

Operators Tops

We started with the state database of tops provided by operators and did a quality assessment from trend surface analysis of the gridded data. This procedure removed extreme outliers and left all tops within a 100 ft interval of the trend surface. Remaining tops were spot-checked against well logs by township and are what we deliver in this dataset. While it is not a perfect set of picks, it is consistent enough for regional work and basin model creation. This dataset contains several thousand tops for each formation from Tertiary to Paleozoic.

Lithostratigraphic Tops

Lithostratigraphic tops were selected at minimum for one well per township. Each top comes with a pick description relating log character to stratigraphic nomenclature. The geology team did multiple quality assurance procedures, including loop ties and regional cross sections. This dataset is the best starting point for detailed stratigraphic analysis in the basin.

Sequence Stratigraphic Tops

This set of tops is based on shale resistivity markers and regional stacking patterns. Multiple regional datums were selected by correlating bentonite beds. The dataset includes regional shale resistivity markers as well as sequence stratigraphic markers tied to lithostratigraphic formation names. Tops have been picked on a regional basis, typically one detailed well every few townships. This dataset is the most accurate for regional relationships in tight sand reservoir systems.