Wyoming State Geological Survey

I spent one year doing contract work for the Wyoming State Geological Survey (WSGS) in Laramie, WY, from May 2017 to May 2018. My first contract position was as a summer field assistant on a mapping project and the second was picking tops to map the subsurface for an unconventional reservoir project.

Mapping the Fort Steele quadrangle

For my first contract I worked with Ranie Lynds to map the bedrock geology of the Fort Steele quadrangle at a scale of 1:24,000. The Fort Steele quadrangle is located in south-central Wyoming, about 20 miles east of Rawlins in Carbon County, and is on the south-western edge of the Hanna Basin. The sedimentary rocks exposed at the surface are Upper Cretaceous to Quaternary in age and are folded and faulted in a series of anticlines and synclines that were formed during Laramide deformation that spanned the Late Cretaceous into the Paleogene. Examples of this type of deformation are visible all throughout Wyoming.

We used field mapping techniques supplemented with previous mapping in the area to create the map using ArcGIS software as well as the Global Mapper and Cross View programs to accentuate the bedrock map and add a cross-section, respectively. In the accompanying report we detailed the sedimentary structures observed, described all map units in detail, discussed the oil and coal potentials in the map area, and provided a description of the geologic history that produced the faulting and folding of the units (Lynds and Wrage, 2017).


Mapping the subsurface in the Powder River Basin

For my second WSGS contract, I worked with Ranie Lynds and Rachel Toner on an unconventional reservoir project in the Powder River Basin. This time my job was to use well data from over 2,000 wells drilled in the Powder River Basin in northeast Wyoming in order to map the extent and thickness of Late Cretaceous units throughout the basin. Basically, I was back to mapping but this time it was formations that are underground.

I used the software program Petra to visualize and interpret the geology and stratigraphy of the Late Cretaceous rocks and made “picks” on the tops and bottoms of the rock units. My efforts were part of a larger project to examine unconventional oil reservoirs in the Powder River Basin and to potentially aid in future production success of oil-bearing rocks that have historically been uneconomical to drill. When used together with recent unconventional drilling practices (i.e. drilling and completion practices, lateral length and orientation), the structure contour (depth to top of formation from surface) and isopach (rock thickness) maps generated using my “picks” can aid industry and regulators in optimizing future oil production in the region.

The first WSGS publication of this topic was a report on the Codell Sandstone in the Denver Basin in southeast Wyoming (Toner and Campbell, 2017). This report is an example of the type of studies that are underway that will use the maps I created in the Powder River Basin. The Codell report is available for free download on the WSGS website.

Citations:
Lynds, R.L., and Wrage, J.M., 2017. Preliminary map of the Fort Steele quadrangle, Carbon County, Wyoming: Wyoming State Geological Survey Open File Report 2017-5, 1:24,000-scale, 25 p.
Toner, R.N., and Campbell, E.A., 2017. Codell Sandstone oil production trends, Northern Denver Basin, Laramie County, Wyoming: Wyoming State Geological Survey Open File Report 2017-2, 40 p.