Effect of Input Parameters on Basin Modelling and Hydrocarbon Resource Assessment of the Northern North Sea
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3D basin modelling and petroleum system analysis of the northern North Sea has been carried out using the Petromod software. The model was calibrated using well 34/8-7 in the Visund field. Different input parameters such as heat flow, source rock properties, fault properties, paleo water depth, source rock kinetics, migration methods and different erosion scenarios have been varied and their effects on the model assessed. The effect of the various input parameters has been assessed in terms of hydrocarbon volumes in the Kvitebjørn and Visund fields, effective stresses (pore and lithostatic pressures), source rock maturity, transformation ratios, hydrocarbon saturations and the time hydrocarbon generation began in the Draupne and Heather Formation source rocks. Risk and resource assessment has been performed on the Kvitebjørn field using GeoX to demonstrate prospect evaluation methodology. Increase in heat flow increases source rock maturity, the start of hydrocarbon generation, transformation ratios and results in the generation of a lot more gas than oil. Generation also starts at shallower depths with higher heat flow. Increasing total organic content (TOC) and hydrogen index (HI) generally results in an increase in the volume of hydrocarbons generated. The increase in HI, however, results in the generation of a lot more oil than gas. High TOC and HI also increase the hydrocarbon saturations in the source rock. Increasing paleo water depth (PWD) has a marginal effect on the model. It increases the volume of oil and decreases the volume of gas marginally. Varying the PWD has no significant effect on source rock maturity, transformation ratios, hydrocarbon saturations and effective stresses. Opening the fault planes resulted in an increase in the volume of hydrocarbons generated. The increase was more evident in the volume of oil than gas. This increase in volumes is a consequence of additional migration pathways created by the faults. Varying the erosion thickness of the Draupne Formation did not have any effect on the model. The kinetics used has a major impact on the type of hydrocarbons generated. Area of closure, reservoir thickness and porosity are the most important parameters in estimating resources in a prospect.