The Strat-Geopressure Fairways: A New Technique Advances Risk Assessment and Prediction of Deeper Potentials, Case History from the Gulf of Mexico

The new technique of integrating stratigraphy and geopressure compartmentalization is a comprehensive risk assessment method of identifying under-explored leads and untapped deeper exploration targets. It also generates a more defined prediction of pore pressure in deeper reservoirs as well as their seal integrity.

Stratigraphy impacts sand (reservoirs) and shale (seals) spatial distribution. The optimum depositional environment for hydrocarbon trapping mechanism lies in the transition zone between the middle and outer shelf paleo-environment, where sand to shale ratio is conducive to sealing juxtaposed fault surfaces.

Geopressure differential plays a principal role in the migration of hydrocarbon from deeper source rocks and carrier beds to the potential closure. The subsurface geopressure profile is usually divided into two main zones: the lower geopressured and the upper hydrostatic. The divergence between the two zones represents the Top of Geopressure. Noteworthy, the transition between the two zones yields a large share of hydrocarbon accumulation

The “Strat-Geopressure Fairway” is the result of integrating the mapped stratigraphic top (maximum flooding surface) and the mapped Top of Geopressure. By incorporating the established producing horizons to these fairways, an essential fast track tool for assessing a prospect, lead and play concept can be applied. Moreover, it delineates the drilled bypass pay zones and potential reservoirs, and sheds light on areas of potential deeper exploration/exploitation targets.

On the Gulf of Mexico Shelf, well logs, seismic velocities, paleo, production, and test data can be integrated in a data base. High Island–Galveston areas were used as a pilot study to test the new model. The optimum exploration trends of the Miocene were clearly following the fairways where stratigraphy and geopressure gradient are conducive for good quality reservoirs with effective seals.