Delimiting Erosion in the Hammerfest Basin, Norwegian Barents Sea: A Probabilistic Basin Modelling View

Matthias C. Daszinnies¹, Krzysztof J. Zieba², Jesper K. Nielsen¹, Ane E. Lothe¹, Asdrubal Bernal³, Hans M. Helset¹, and Ute Mann^1
1Basin Modelling Group, SINTEF Petroleum Research, Trondheim, Norway.
²NTNU - Norwegian University of Science and Technology, Trondheim, Norway. (3) Statoil ASA, Harstad, Norway.

The hydrocarbon potential of the Norwegian Barents Sea was shown by the gas discoveries in 1980 in the Hammerfest Basin (e.g. Snøhvit Field) and recent oil findings (e.g. Goliat Field). Successful hydrocarbon exploration in the Norwegian Barents Sea is challenged by a lack of sound understanding of the petroleum system’s dynamic response to the basin evolution. Dry traps often indicate a history of filling and subsequent emptying, which is generally thought to result from hydrocarbon redistribution and leakage due to uplift and erosion episodes. Unfortunately, these episodes are not well constrained.

Erosion estimates are crucial in reconstructing basinal burial histories, which constitute a key input to basin models. However, magnitude, lateral and temporal distribution of erosion estimates impose high uncertainties on derived burial histories and modelled petroleum systems. Methods quantifying erosion (e.g. VR, AFTA) often yield very different magnitude estimates. Deterministic basin models on the other hand, provide only single model solutions and do not account for uncertainties inherent to input data. We approach this challenge by using Monte Carlo basin modelling simulations, where input data for SINTEF’s in-house basin modelling software SEMI are described by probability distributions, and model results are evaluated statistically.

We will investigate a Mesozoic petroleum system where the Stø Formation is a carrier unit that is charged with hydrocarbons from the source rocks of the Kobbe and Hekkingen formations. Erosion events in Eocene-Oligocene and Miocene-Pleistocene times are regarded as the most significant in the Hammerfest Basin in younger times. By varying the erosion amounts in each event, we will investigate the influence of magnitude and timing on the petroleum system, e.g. on hydrocarbon migration patterns. Through the calibration of the model results against measured well column heights we also seek to delimit erosion magnitude ranges in each erosion event.

We will present and discuss representative cases demonstrating the influence of erosion on selected basin model parameters, kerogen maturation, secondary migration and entrapment patterns in the Hammerfest Basin. Furthermore we will discuss spans of erosion estimates yielding reasonable solutions for the various basin model scenarios.

Acknowledgements:
This work is a contribution to SIP 186919 funded by The Research Council of Norway.

 

AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.

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