Numerical Modeling of the Deformation and Displacement of Salt Bodies With Embedded Carbonate or Anhydrite Stringers

Abstract

Large carbonate or anhydrite inclusions are embedded in many salt bodies (so-called rafts, floaters or stringers) and these respond to the movements of the salt in a variety of ways, including displacement, folding and fracturing. The movement and deformation of those embedded carbonate or anhydrite bodies is a process which is not fully understand yet. No numerical study yet has investigated the brittle deformation of individual stringers during the initial phases of salt tectonics. We presented numerical models of the deformation of salt body with embedded stringers using a case study from the South Oman Salt Basin. We investigated by Abaqus package (finite element models) how differential displacement of the top salt surface induces salt flow and the associated deformation of brittle stringers (including both brittle and viscous material properties). In our research, the main work was to use and develop techniques in Abaqus to make models of rheological behaviour of salt tectonics and brittle or ductile behaviour of carbonate stringers embedded in salt. A series of techniques were used in order to make successful models. We simplified the geometry from seismic data, define carbonate or anhydrite and rocksalt material, model passive tectonic process through applying boundary conditions, model large displacement through adaptive remeshing technique and python script, model brittle fracture through iterative scheme for stringer breaking and adaptive remeshing techniques. The simplified model offers a practical method to investigate complex stringer motion and deformation. Models suggest that brittle stringers can break very soon after the onset of salt tectonics. The extension can make brittle stringer to boudinage and fracturing and compression can make brittle stringer bending and thrusting. Models suggest that viscous stringers have folding and extension deformation. Results also show the internal structure of salt body and stringer fracturing or deformation is strongly dominated by the geometry or material properties of models.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017