The Application of Capillary Based Migration Modelling to Fault Moderated Fill and Spill

Dee, Stephen J.¹, Brett Freeman², Dan Carruthers³, Graham Yielding², Peter Bretan² (1) Badley Geoscience Limited, Hundleby, Lincolnshire, United Kingdom (2) Badley Geoscience Ltd, Lincolnshire, United Kingdom (3) The Permedia Research Group Inc, Ottawa, ON

Petroleum migration occurs at geological timescales and solving petroleum flow trajectories and emplacement patterns can be accomplished with modified invasion percolation techniques. These algorithms honour the salient controls on petroleum flow while having the advantage of low computation times.

The migration model is defined as a dense, regular, 2D or 3D grid of properties. As fault bounded traps in siciliclastic rocks frequently depend on capillary seal to retain hydrocarbons, estimates of fault zone properties such as SGR (shale gouge ratio) can be used to estimate threshold capillary entry pressure. Faults are introduced directly into the model by their capillary properties at the appropriate grid cell. Petroleum fluids are introduced at pre-specified locations and are free to move according to the balance of the local water pressures, petroleum buoyancies and resistive capillary pressures.

By tightly integrating the invasion percolation modelling with fault property modelling code within high resolution geological property models, multiple fill scenarios can be tested. Speed of processing also encourages risk analysis by facilitating rapid evaluation of multiple scenarios for the same geometric configuration, leading to an assessment of the uncertainties in the analysis.