PRATSCH, JOHANN-CHRISTIAN, Integrated Frontier Exploration, Houston, TX

ABSTRACT: Major Oil and Gas Possibilities in Miocene and pre-Miocene Reservoirs, Texas/Louisiana Shelf, Gulf of Mexico

All oil and most gas reservoired in and produced from late Miocene and Pliocene/Pleistocene reservoirs in the Gulf of Mexico offshore have been generated in Mesozoic and perhaps Paleogene source beds. Late Miocene

and Pliocene/Pleistocene reservoirs are thermally immature. This indicates major vertical and lateral hydrocarbon migration since about mid-Miocene, and a two-stage migration history: Most present oil and gas fields in late Miocene to Recent reservoirs in the central Gulf Coast offshore are secondary fields. They result mainly from migration or seepage of oil and gas from primary fields. Their common source beds are too deeply buried to be effective oil generators today. Proved reserves in secondary fields are over 10 billion bbl oil and 130 Tcf gas. Primary accumulations in yet undetected Mesozoic, ?Paleogene and Miocene reservoirs may have oil and gas reserves considerably larger than those in established secondary fields. Primary accumulations are the targets of the new play. They ill be found in areas of critical hydrocarbon concentration and along major migration pathways; both can be defined today using available gravity, magnetic and seismic data. Modern seismic data allows mapping of numerous mainly large structural anomalies. They are undrilled. Shallow-water economics and existing technology enhance these targets over existing deep-water prospects. Acrage is available.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.