Gibergues, Natacha, Muriel Thibaut, Institut Francais du Petrole, Rueil-Malmaison Cedex, France
The 3D coupled backward and forward deformation of basin models can be treated with a mechanical or a kinematic approach. Because of the difficulty met with the mechanical approach we adopted a kinematic approach which is supposed to be sufficiently representative of the natural processes.
The model proposed here considers two mechanisms of deformation: the vertical shear and the flexural slip. For both, we ensure the preservation of the thickness of the layers, and of area of the neutral surface. The methodology is 3D, reversible and simple to implement.
The model was first validated in 2.5D on a cylindrical basin, then on a 3D model with a lateral variation for the strike of the ramp from 10° to 25°, and, finally, on a model with a curb ramp. Different mechanisms of deformation may be applied to each layer of the basin and layers are independent one by one. For different increments of displacement (500m to 2km), the models present a shape with a coherent geometry.
The great simplicity of the hypothesis allows a easy handling of more complex models.