--> Abstract: Evidence for Oil in Lower Miocene Turbidites in South-West Trinidad, a Petroleum Systems Approach, by Krishna M. Persad; #90078 (2008)

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Evidence for Oil in Lower Miocene Turbidites in South-West Trinidad, a Petroleum Systems Approach

Krishna M. Persad
K. Persad & ASSociates Ltd., Miami, FL

The Upper Cretaceous Naparima Hill Argillite and the Gautier Shales are now generally accepted as the source for virtually all the oil and most of the catagenic gas found in Trinidad, onshore and offshore.

In the onshore and western offshore of Trinidad, two petroleum systems have produced the majority of oil to date. Both have the upper Cretaceous rocks as the source.

One, the Gautier/Naparima Hill-Cruse/Forest/Morne L’Enfer (!) System, has as its reservoir, near-shore deltaic and marginal marine rocks mainly of Pliocene age.

The second, the Gautier/Naparima Hill-Cipero (!) System has as its reservoir, deep water turbidite sand members of the Lower Miocene Cipero formation. The Herrera member has produced over 200 million barrels of oil to date and an exciting gas/condensate discovery has recently been made, all onshore.

To the present however, the Herrera reservoir has seen no commercial production west of the Los Bajos fault, onshore or offshore. Indeed penetrations of this reservoir have been extremely rare and the extent of the system is not well known.

Geochemical work on HRGC’s of oils from shallow Pliocene reservoirs indicates the presence of deeper oil, which we believe to be reservoired in Herrera sands.

This postulation is supported by hydrocarbon shows in the only two known penetrations in the area and by oil-sands ejected from two mud-volcanoes within the area. The oil-sands show lithology distinctive of the Herrera and Retrench members of the Cipero and are saturated with residual oil.

A number of deep structures, with large potential, have been identified and future drilling may result in commercial production.

 

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas