Abstract: Integrated Gravity Modeling of Salt Features in the Mississippi Salt Basin

Rhonda L. Schenk, John J. Morris, Stuart A. Hall

Recent exploration in portions of the Mississippi Salt Basin indicates that many models used in the interpretation of surface and subsurface data may be inadequate to explain several salt features. Models are important in interpretation due to the depth of the objectives and the complexity of the salt ridges. Significant oil and gas reserves trapped by the salt and related faults in Upper Jurassic reservoirs were discovered from the early 1960s to the late 1980s using an anticlinal model. However, in the course of further drilling, the formations and the underlying salt were not encountered where predicted by the anticlinal model suggesting that many of the salt ridges in the basin are more complex.

This study uses an integrated approach to test the viability of a more steeply dipping salt ridge model, compared to a salt anticline, for the interpretation of surface and subsurface data. Seismic reflection profiles in conjunction with gravity data and well log information form the data base with which salt models were evaluated. Eucutta Field and Diamond Field were selected as test areas for the salt models based on the availability of data. The two fields are located along different types of parallel salt ridges.

Results of the study indicate that the salt ridges are a hybrid of the two models with a more gentle dipping anticline shaped feature on the landward side. The salt ridges also appear to have a complex along-strike variation in the structure of the salt.

AAPG Search and Discovery Article #90950©1996 AAPG GCAGS 46th Annual Meeting, San Antonio, Texas