New Insights into the Eastern Margin of the Tuxpan Platform and its Influence on Deepwater Plays of the Gulf of Mexico

摘要

Geological and geophysical studies were carried out with the main objective being the updating of the depositional model for the Tamabra Formation of Cretaceous (Albian-Cenomanian) age, on the eastern (offshore) side of the Tuxpan Platform, located on the southeastern side of the Tampico Misantla Basin, México. For many decades, productive fields in this formation are known to lie in a belt located on the western (onshore) side of the Tuxpan Platform, of which the Poza Rica Field is the best known example and demonstrates a combination (stratigraphic/structural) trap mechanism. Along the onshore Tamabra Formation trend, facies of carbonate debris flows form the primary reservoir facies. By contrast, the "Tamabra Formation" off the eastern (marine) side of the platform has only been penetrated by two non-commercial wells, well A and well B. In particular, the reservoir rock is thin, but it shows acceptable reservoir quality even at depths of more than 5200 m. Nevertheless, recently undertaken specialist studies, including petrography, cathpdoluminescence, fluid inclusion analysis of material from the two wells, plus seismic facies mapping have provided evidence that the Tuxpan Platform, its former slope and sometimes underlying basinal facies, have suffered significant erosion. This was due to significant structural uplift of a zone running just to the east of the present-day Marine Tuxpan Platform; this uplift and erosion combined with eustatic influences and resulted in a very notably different present-day limit to the Tuxpan Platform, to that which was present in the Albian-Cenomanian. The "Tamabra" encountered in well A and well B has emerged as a Late Cretaceous (Late Cenomanian/Turonian and younger) deposit which was largely derived from erosion of the eastern margin of the Tuxpan Platform and its slope. Because of this, true Tamabra facies of Albian-Cenomanian age in this area, have not been tested.