Three Dimensional Restoration of Hanging-wall Volumes: A Continuum Approach

Tim S. Buddin, Stuart S. Egan, Steve J. Kane, and Graham D. Williams

Restoration of balanced cross sections in two dimensions is commonly used in the oil industry in order to validate complex geological structures. Three restoration algorithms that are ordinarily applied are: the vertical shear (Chevron) construction; the inclined shear construction and the flexural (Suppe) construction. Our research has involved the restoration of hangingwall volumes in three dimensions assuming a rigid footwall and deformable hangingwall block. All three algorithms have been applied in 3-D sensitivity testing by considering the `goodness of fit' (mean absolute residuals) between original and restored marker surfaces following deformation and restoration by different routes. We have quantified and mapped the degree of misfit of restored surfaces across the complete range of restoration routes and are able to predict the degree of potential misfit in restored 2-D cross sections involving movement of material into and out of the section plane. Research has recently concentrated on flexural-type constructions and using continuum approach a 3-D model has been developed for the motion of laminar flow of the hangingwall over faults of complex geometry. Creeping flow equations rather than geometrical construction techniques have been used to model hangingwall deformation. The algorithms are truly 3-D and mass (equating to volume) in the hangingwall is conserved between restored and deformed states. The method is particularly applicable to interpretations from 3-D seismic data sets and is currently undergoing testing using real data. Because the method is truly 3-D we have the ability to model all modes of deformation including contractional, extensional, wrench and oblique slip.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California