PETERSEN, KENNETH, and IAN LERCHE, Department of Geological Sciences, University of South Carolina, Columbia, SC

ABSTRACT: Self-Consistent Quantitative Models of Interactive Salt and Sediment Evolution: Case Histories from Gulf of Mexico

Hydrocarbons are often associated with traps developed on the flanks and on the crests of salt structures. Previously, models have been designed to delineate the evolution of salt structures, but so far it has proven difficult to provide quantitative procedures for assessing the combined self-consistent evolution of salt and associated sediments.

A novel quantitative model is presented that is guided by observational information on the shape of salt structures and the surrounding sedimentary formations. The present-day shape of salt structures is constrained by an inverse non-linear procedure guaranteeing the predicted shape to be in close correspondence with the observed present-day salt shape. By introducing time-dependence of each of the shape-controlling parameters, and by letting sedimentary beds move around the evolving salt the interaction between sedimentation and the developing salt is depicted. Assumptions can then be made of paleo-sediment surface geometries, compactional histories, and salt volume conservation, there by constraining the time-dependence of parameters controlling the dynamic evolution of the salt.

Applications are given to salt diapirs in the North Louisiana salt basin quantifying extent and location of allowed salt overhangs and salt widths. Furthermore, assessments are provided of the combined evolution of salt and sediments discussing the importance in predictions of possible hydrocarbon plays.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.