How to Benefit from Monte Carlo Simulations in Petroleum Systems Modelling to Estimate the Amount of Erosion

Erosion estimates are crucial in reconstructing the burial history of the Barents Sea basins, where the lack of major success in oil exploration is attributed to the Cenozoic uplift and erosion. The magnitude, lateral and temporal distribution of erosion estimated by methods like AFTA, VR or by deterministic basin modelling often leads to very different results and/or does not account for uncertainties inherent to input data. Here, this challenge was approached by using Monte Carlo – secondary migration basin modelling simulations, where input data (early and late Cenozoic erosion episodes and palaeo-thermal gradients) were described by probability distributions, and model results were evaluated statistically. Two overpressure scenarios were also considered in the modelling. Constrained a posteriori erosion parameter distributions showed a relatively narrow range of possible solutions. It was shown that the early Cenozoic erosion episode was more severe than the late Cenozoic event. A posteriori distribution mean values were much lower than a priori mean values (which represent initial beliefs) suggesting lower amount of erosion than expected. Overpressure modelling does not affect the minimum and the maximum erosion amount estimates to a high degree. Slight differences might be however observed for the early Cenozoic erosion event.