An Evaluation of the Resource Potential of the Tyler Foirmation (Pennsylvanian) using a Basin Centered Petroleum Accumulation Model

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The Tyler Formation (Lower Pennsylvanian) is a regionally extensive, organic rich unit that contains, over a significant part of its range, good to excellent quantities of kerogen. The richest kerogen is situated in the deepest portion of the Willston Basin (McKenzie County) and consists of marine derived organic matter that is prone to producing both oil and gas. Less rich kerogen is present along the flanks of the basin. This kerogen is dominated by terrestrial organic matter that is more likely to generate gas. A basin maturation model calibrated with experimentally derived kinetics and log based thermal stratigraphy indicate that there are two and possibly three portions of the Williston Basin in which the Tyler Formation is currently within the oil window. Tmax values obtained from Rock Eval 6 analysis and the distribution of high resistivity shale are consistent with the maturation trends detailed by the basin analysis. Two of the areas that exhibit thermal maturity include known economic and sub-economic oil production, some of which is associated with over-pressurized formation fluids. The combination of organic rich source beds, thermal maturity and over-pressurized conditions is consistent with the basic requirements for a basin centered petroleum accumulation similar to the Bakken Formation. Unlike the Bakken, a sufficiently thick and laterally consistent reservoir has not been identified that would allow for the routine installation of horizontal well bores. However, additional work may find suitable targets in and adjacent to known sandstone reservoirs or in mechanically competent, units in the overlying upper Tyler Formation or underlying Otter Formation.

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  • Report


  • critical issues, database publication, oil and gas, energy, north dakota