--> ABSTRACT: Four-Dimensional Modelling of Basin Processes, by Graham D. Williams, Andrew J Richards, and Stuart M. Clarke; #90906(2001)

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Graham D. Williams1, Andrew J Richards1, Stuart M. Clarke1

(1) Keele University, Keele, United Kingdom

ABSTRACT: Four-Dimensional Modelling of Basin Processes

The basis of four dimensional basin modelling is structural retro-deformation and forward modelling by sequential movement on faults with associated hangingwall and footwall deformation. An Earth Model is composed of three dimensional surfaces representing stratal surfaces, faults and unconformities. Attributes representing various rock properties beneath each stratal surface are assigned to surface nodes.

To model an extensional basin, the newly-developed modeling technique involves retro-deformation plus backstripping of sediment layers, performed in sequence, from present day to the oldest sequence recognised. The post-rift sequences are removed in reverse order of deposition; the removal of the syn-rift sequence is accompanied by automated fault restorations. The sequence of fault movement and the displacements of adjacent fault blocks are stored for use in forward modelling, which incorporates thermal parameters and predicts the petroleum system through time. Cross fault juxtaposition of strata and fault zone processes such as smearing and cataclasis have been incorporated into 3-D transmissibility models based on invasion percolation (IP). The effects of fault zone processes on fluid flow are incorporated into four dimensional forward models which, through the IP algorithm, calculate hydrocarbon fluid flow pathways controlled by lithology (transmissibility distribution) and evolving structural geometries in rock volumes.

Because structural geology in three dimensions is the basis for basin modelling, it is possible to model basins of any type including thrust-, extensional-, wrench-related and inverted basins. It is realistic to run several basin models with varying parameters in order to generate best-case and worst-case scenarios in prospective areas.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado