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Basin Modeling Study of the Uinta Basin, UT

Abstract

The Late Cretaceous Uinta Basin is located in northeastern Utah within the northern most portion of the Colorado Plateau. The maturity of source beds in the Parachute Creek Member of the Green River Formation were impacted by the basin's uplift and subsidence history and thermal evolution. We constrained the subsidence and thermal history using sixty wells along three NS lines. The wells reached into basement, and four wells provided vitrinite reflectance measurements. All models were calibrated to measured data, including vitrinite reflectance and transformation ratios from Rock-Eval pyrolysis. We were able to constrain timing and amplitude of uplift of the northern Colorado Plateau. The models predict that the heat flow ranges from 65 mW/m2 to 45 mW/m2 from south to north in the study area. Additionally, model calibration provides a means for estimating the amount of uplift and erosion in the Uinta Basin. Uplift predicted for the Uinta Basin ranges from ∼2050 m to ∼2200 m and started in the Late Miocene. Based on the eroded thicknesses and heat flow values determined from calibration to measured thermal maturity indicators, the maturity of the rich oil shales of the Parachute Creek Member was inferred. Model predictions have suggested that source intervals of the Parachute Creek Member follow a general trend of increasing maturity from south to north in the study area. Local variations in predicted maturity that deviate from this trend most likely occur due to the effects of decreasing heat flow outpacing the effects of greater burial depths from south to north.