Oil Generation Rate Index Using Arrhenius Equation for Bakken Formatio

Oil generation rate index is important in considering oil well performance. An oil generation rate index was estimated for ten wells in the Bakken Formation in the North Dakota portion of the Williston Basin. Activation energies consistent with a fixed frequency factor (1x10--14/sec) and estimates of the current temperature within the Bakken Formation were used to calculate a reaction rate. The reaction rate was converted into a generation rate index by multiplying the reaction rate by the mass of crackable kerogen derived from programmed pyrolysis (SRA) S2 analyses and bulk density logs. The programmed pyrolysis temperature of 435 °C, production index of 0.1 and conversion fraction of 0.1~0.15 are generally considered to represent the threshold of intense hydrocarbon generation from mature rocks. The calculated reaction rate index appears consistent with overpressure and production.