Investigating the effectiveness of using basement heat flow as a tool for modeling the thermal history of a basin in a 1D basin model

Abstract

The goal of this project is to investigate the effectiveness of using Basement Heat Flow and Platte River Associates, Inc. (PRA) 2014 approach of finding the sediment-water/air interface temperatures to estimate the thermal history. This was carried out by creating 1D wells models in the Williston, Uinta, Paradox, and Norwegian North Sea basins in the BasinMod® software. These models were also used to investigate the effects of different tectonic histories, erosion estimates, and thermal properties of kerogen on thermal indicators in the basin. Multiple scenarios with different settings were carried out on each well model until a model that matched the measured data was produced. A thermal history in each basin was successfully derived. The most reasonable models for the Williston Basin that matched the measured data included either a failed Tertiary rift or a basement conductivity anomaly in order to explain high maturities in the basin center although there is little to no evidence to support either theory. The models for both the Uinta and Paradox basins included thinning of the mantle lid followed by thickening of the crust during the Tertiary due to their location on the Colorado Plateau. Thinning the mantle lid during the Tertiary and having a thin present day mantle lid thickness of 60km was crucial for the maturation of the source rocks in the Uinta Basin model. The temperature histories in these two basins were slightly different because of their different locations on the Colorado Plateau and the deposition of highly conductive salt in the Paradox Basin. In these three basins (Williston, Uinta, Paradox), the rapid deposition of shale in the Cretaceous Western Interior Seaway created a thermal blanket that either enhanced or hindered maturation of source rocks. For the well models in the North Sea, a thinner mantle lid during the Tertiary was required to mature the source rocks; therefore the models that included a rifting or thinning event later than the Permo-Triassic rift event best matched the measured data. Other conclusions made from the model 1) constrain the amount of erosion in the Williston, Uinta, and Paradox basins, and 2) determine that including the thermal properties of kerogen in the well models would not impact the thermal history especially in thin source rock with lower TOC content. The Basement Heat Flow tool and Platte River Associates, Inc. (PRA) 2014 approach of finding the sediment-water/air interface temperatures were effective in estimating the thermal history. This process of determining the tectonic history of the basin can be complicated by anomalies and hydrodynamic flow but the other factors included in the calculations of the subsurface temperatures and heat flux are valuable in determining the thermal history of the basin.