THERMAL MATURATION MODELING OF THE MICHIGAN BASIN

Given present day heat flow and burial depths in the Michigan Basin, hydrocarbons should be immature. However, oil and gas are abundant within the basin. Our goal is to test the hypothesis that thermal maturation distributions in the Michigan Basin are related to proximity from the Midcontinent Rift system, thermal cooling, crustal convection, high temperature fluid advection, and eroded overburden. In this work, this range of geodynamic models will be applied to seven wells across the Michigan Basin that bottom near or in basement rock, have different spatial distributions relative to the Midcontinent Rift, and are in close proximity to wells with thermal maturation data.

For each well a geohistory plot will be coupled with heat flow models to calculate the thermal and maturation histories of each sediment unit within the well. Backstripping will be performed in order to generate basement heat flow estimates. Time temperature index values will be calculated based on the thermal models. Comparison of calculated time temperature index values and recorded thermal maturation data from surrounding wells will test our hypothesis.

Preliminary results reveal observed thermal maturation data in each of the seven wells cannot be explained by present day heat flow within the Michigan Basin. Most locations in this study must have experienced higher geothermal gradients in the past in order to match observed thermal maturation data. Currently, two wells within this study require geodynamic modeling that includes thermal cooling, crustal convection, high temperature fluid advection, and eroded overburden in order to match surrounding thermal maturation data. More work still needs to be done to analyze how proximity to the Midcontinent Rift system effects thermal maturation and which geodynamic models tell the most accurate story of the thermal history of the Michigan Basin. The results of this study will reveal important information on the burial and thermal maturation histories of the Michigan Basin.