ABSTRACT

Assessment of the combined evolution of salt and surrounding sediments is one of the major problems in salt-dominated basins. A quantitative approach, guided by observations from seismic and/or well data, is presented. The present-day shape of a salt structure is constrained by an inverse non-linear procedure which determines the parameters controlling the salt shape. The shape is shown to be in close correspondence with the observed present-day salt shape. By introducing time-dependence of each of the parameters controlling the salt shape, the procedure permits an assessment of an evolving salt shape with time. By letting sedimentary beds move around the developing salt structure, the influence of the uprising salt on the evolving bed geometries above and around the salt is depicted. As the predicted present-day bed geometries must also be in accord with the observed rim syncline bed geometries, additional constraints are put on the parameters controlling the dynamic evolution of the salt structure. The inverse procedure automatically determines, in a self-consistent way, resolution and sensitivity of all parameters in the quantitative model, and also of the dynamic evolution of both the salt and the surrounding sedimentary formations. The procedure also handles asymmetric two-dimensional structures as well as symmetric three-dimensional structures. Introduction of basement heat flow permits assessment of the thermal focusing effect of the evolving salt relative to the surrounding sediments which, in turn, permits an estimate of the timing of maturation of possible source rocks, migration and possible trapping below salt overhangs, or in reservoirs developed above and along the flanks of the salt.