Three-Dimensional Visualization of Salt Walls and Associated Fault Systems

Abstract

Abundant three-dimensional (3-D) seismic data from salt provinces have been acquired over the past two decades. These data have been interpreted partly using concepts based on analysis of two-dimensional (2-D) sections through physical and numerical models. Three-dimensional computer visualization of physical models is a recent development that exploits the full potential of model data by displaying even highly irregular geological structures such as convolute salt contacts, strata disrupted by salt tectonics, discontinuous faults, and bedding traces on fault surfaces. We used computer visualization techniques to display and analyze a physical model simulating salt-related structures produced during gravity spreading and gliding. The visualization shows, in realistic 3-D detail, that (1) structures change seaward from tall steep-sided diapirs to squat salt rollers; (2) salt walls change markedly along strike and form branches and relays; (3) subsidence of underlying salt ridges produces irregular turtle-structure closures that tend to have multiple seals; (4) links that laterally connect reservoirs in adjacent rafts are most common in upper stratigraphic ©Copyright 1997. The American Association of Petroleum Geologists. All rights reserved.1Manuscript received November 1, 1995; revised manuscript received March 4, 1996; final acceptance August 12, 1996. 2Bureau of Economic Geology, University of Texas at Austin, Austin, Texas 78713. Additional full-resolution color 3-D images and digital animations related to this paper are available free on the Internet at http://www.utexas.edu/ research/beg/mmedia/AGL96-MM-004. We wrote this paper while testing an unreleased version of the program EarthVision® and working with its creators at Dynamic Graphics Inc. to enhance the technology for visualizing complex brittle and ductile structures. Dynamic Graphics Inc., especially Raphael Mayoraz, provided invaluable technical support. Shing-Tzong Lin provided unpublished cross sections of the physical model that he created under our supervision. Hongxing Ge digitized the model data. The research was funded by the following companies in the Applied Geodynamics Laboratory consortium: Agip, Amoco, Anadarko, ARCO/Vastar, British Petroleum, Chevron, Conoco/Dupont, Elf Aquitaine, Exxon, Louisiana Land and Exploration, Marathon, Mobil, Petrobras, Phillips, Statoil, Texaco, and Total. K. Prewitt and T. Weaver edited the figures. T. Hentz edited the paper. J. Farre, R. Ray, and B. Blake refereed the paper, which is published by permission of the director of the Bureau of Economic Geology, University of Texas at Austin.