Computational Forward Modelling of Salt Tectonics in Varied Tectonic Settings: Computational Challenges, Applications, and Future Directions
Deformation of sedimentary sequences due to movement of mobile salt layers produces a wide variety of structural styles. Much of our understanding of the controls on structural expression during salt tectonics is derived from physical modelling. These experiments have explored salt tectonics in compressional, extensional, and strike-slip stress environments and have had great success in producing structures which closely resemble those observed in the subsurface. These models are however limited in the quantitative information they can provide, and the simplified representation of the materials fails to capture the complex behaviour of salt and adjacent sediments which are strongly dependent on stress, pressure, temperature and mineralogy. More recently, increased computational power has seen the development of forward models that are able to study the evolution of salt structures over geological time. When coupled with sophisticated and realistic constitutive laws for the salt and sedimentary sequences a large amount of quantitative data can be extracted to help constrain the deformation history and present day conditions. However, due to computational constraints much of this work has been in two dimensions and therefore fails to precisely capture the complex three-dimensional geometry of salt bodies that is commonly observed in seismic data sets. There is in general a paucity of studies that treat the numerical analysis of salt tectonics in three dimensions, and this is motivation for undertaking the present study. This work discusses the pre-requisites for using three-dimensional computational forward models to try and constrain structural evolution and estimates of pre-drill stress and material state. Benchmarking of the models against analogue studies is provided to show the potential of the computational method. Field scale examples are provided featuring complex, multiaxial deformation histories in which determination of the full stress tensor is considered important and the implications for operational activities are highlighted.
AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019