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Graham D. Williams1, Andrew J. Richards1, A. J. Dodds1, S. M. Clarke1
(1) Basin Dynamics Research Group, Keele, Staffordshire, United Kingdom

Abstract: Integrated three dimensional basin modelling

An integrated suite of basin modelling software has been developed using C++ and OpenGL for the Windows NT platform. The fundamental basis for basin modelling is structural retro-deformation and forward modelling. An Earth Model is generated from a 3D or 2D seismic interpretation plus wells and is represented by three dimensional surfaces composed of nodes which form triangular meshes. Stratal surfaces, faults and unconformities are generated and visualized in the Earth Model. Attributes representing various rock properties are assigned to surface nodes and may vary laterally through the Earth Model or in depth across different stratal surfaces. Faults and unconformities are treated as two surfaces occupying the same position in 3D space; attributes representing either fault or unconformity properties or adjacent rock properties are assigned to both surfaces.

In a simple basin model, retro-deformation plus backstripping of sediment layers is performed, in sequence. At each restoration step the following adjustments are made to the Earth Model:

  • sediment is backstripped and decompacted using a simple Athy-type relationship
  • flexural isostatic adjustment is made in response to removal of sediment load and fault displacement
  • rock material properties, such as porosity and density, are changed

Each restoration step is stored for use in the forward modelling run. The forward model incorporates thermal parameters and predicts the petroleum system through time. Maturation of various types of kerogen and migration due to buoyancy are modelled and hydrocarbon accumulations in a variety of trap types are predicted for each time step. Continued forward modelling causes trap geometries to be modified and secondary migration and re-accumulation takes place. It is possible to model basins of any type including thrust-, extensional-, wrench-related and inverted basins.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana