Nick Jones of EORI explores the application of Permian Basin ideas to the Bighorn Basin through the use of cores, cuttings, well logs, PI cards, and more.

Osage Partners, LLC. a Wyoming based operator contacted EORI and requested the institute’s assistance regarding their Muddy/Newcastle assets. The operator provided EORI with core from four wells and associated data related to the Osage field in the Powder River Basin. The operator requested that EORI characterize the clay mineralogy of the pay sands using XRD, SEM, and CEC analysis of samples from the provided core.

Eolian petroleum reservoirs are found worldwide, many having high-volume production of both oil and gas. As with any geological rock unit, each oil/gas field has production characteristics peculiar to its geological history. However, certain common factors link most eolian reservoirs. Cross-stratification due to bedform migration can influence sweep direction and efficiency. The various kinds of primary eolian strata have different poroperm characteristics. Moreover, stacking of sand seas or bedforms through geological time can create distinctive reservoir flow units in the subsurface. Tectonic activity, especially faults, may create shear zones with reduced poroperm, or partition a reservoir into structurally defined flow units. Faults may also create high-permeability zones that allow water breakthrough. Eolian reservoirs are commonly thought of as clean, and rather simple. However, in some places they are complex in terms grain composition or texture. They are commonly cemented by carbonates, anhydrites or salt, which sets up fabricselective or non-fabric selective patterns of secondary porosity in reservoirs.

There are two main themes of this poster. The first theme is to provide an update on the stratigraphy and sedimentology of the Tensleep/Casper Formation of Southeast Wyoming (and parts of Northern Colorado), and oil production from these rocks. We incorporate new measured sections, stratigraphic analysis and petrographic work undertaken by the authors. To this end we created a new database in ArcGis (geographic information software) of tops and other information that updates the historical well database of the Wyoming Oil and Gas Commission archived in Casper. This new database has been used to create Common Risk Segment (CRS) maps of the Upper Tensleep oil play in Southeast Wyoming. These CRS maps indicate trends in Tensleep reservoir, charge and trap that are useful in planning further exploration. It is possible that use of advanced seismic techniques applied over the complex structural terrains in the identified high potential areas of SE Wyoming will produce new leads and ultimately, new discoveries.

Ash Minnelusa Unit Conclusions

• Monitor, monitor, monitor. Make changes based upon reservoir response.
• Improved understanding of the problem improves process application and results
• Volumetric sweep (gels) should be applied before mobility control
• Implement gel processes early for maximum benefits
• Incremental oil expected to exceed 400,000 BBLS (18.4%%5 OOIP) for $0.88/BBL
• Field experience is critical with gel processes. Experience at Ash can be applied to other reservoirs