POSSIBLE UNTAPPED HYDROCARBON PLAYS IN THE MUDDY FORMATION OF THE BIGHORN BASIN, WYOMING

The Bighorn Basin of north-central Wyoming and south-central Montana has been commercially producing hydrocarbons since the early 1900s. Its structural and stratigraphic histories form a multitude of petroleum plays, including those in the Thermopolis/Muddy/Mowry complex. While these units have been drilled many times before, the aim of this research is to predict potential play areas that may still be profitable. In order to define a zone of prospective drilling, geographical boundaries must be drawn based on a set of limiting factors, such as quality of hydrocarbon and reservoir, formation thickness and depth, and structural and stratigraphic seeps. Some of this information is drawn from well logs, but the majority depends on previous interpretation of distinct and diverse researchers. Conflicting explanations can create data incongruity, the meaning of which must be interpreted, permitting operator error.

This research is a continuation of team work completed at the 2015 ExxonMobil Bighorn Basin Field School. Initially, it was determined that both structural and stratigraphic traps exist in the Muddy. However, the structural traps have been extensively exploited, and the existence of the stratigraphic trap is compromised by limited and questionable facies change data. The team’s final conclusion was that drilling in the Muddy would not be profitable. I will present further analysis based on more extensive research that aims to more accurately define all limiting factors, especially the facies changes.