Paleogeothermal gradients and timing of oil generation in the Belden Formation, Eagle Basin, northwestern Colorado

Paleogeothermal gradients and timing of oil generation for the Lower and Middle Pennsylvanian Belden Formation have been estimated for four locations in the Eagle Basin of northwestern Colorado, by comparing measured vitrinite reflectance with maturity modeling. Two thermal models were made for each location: one assumes a constant paleogeothermal gradient through time while the other is a two-stage model with changing paleogeothermal gradients. The two-stage paleogeothermal gradient scenario is considered more geologically realistic and is used to estimate the timing of oil generation throughout the Eagle basin. From the data and interpretations, one would expect Belden oil to be found in either upper Paleozoic or Mesozoic reservoir rocks. -Authors