MATHALONE, JEREMY M. P., Eurocan USA, Inc., Houston, TX, and MANUEL MONTOYA, Petroperu, Lima, Peru

ABSTRACT: The Petroleum Geology of the Sub-Andean Maranon-Ucayali Basin, Onshore Peru

The Maranon-Ucayali Basin Complex covers seventy five million acres east of the Andes. It trends north to south from the Ecuadorian Border where it is synonymous with the Oriente Basin, to within 200 kilometers of the Bolivian border.

The stratigraphy of the basin ranges from Ordovician to Recent, covering remnants of larger Lower and Upper Paleozoic and Mesozoic basins. The basin is currently the foreland trough of the overthrusting Eastern Cordillera and, in common with many other sub-Andean Basins is a Miocene to Recent feature.

Three main compressional structural events are usually visible on seismic data, a Hercynian (Carboniferous-Permian) episode in the Ucayali Basin, or Triassic event in the Maranon Basin, followed by Lowermost Cretaceous uplift and erosion and strong Miocene (Quachua) compressional folding.

Oil prone source rocks are recognized mainly in the Devonian, Permian and Cretaceous, but with significant potential in the Triassic and Jurassic. Four main families of oils have been identified, of which three correlate with Cretaceous and Permian source rocks and one with neither. Approximately one billion barrels of oil and five trillion cubic feet of wet gas have been discovered to date, almost exclusively reservoired in Cretaceous deltaic to shallow marine clastics. A variety of trap types have been identified for which examples will be presented.

These range from basement involved and detached thrust faulted anticlines, to inversion and combination drape/compression anticlines.

AAPG Search and Discovery Article #90988©1993 AAPG/SVG International Congress and Exhibition, Caracas, Venezuela, March 14-17, 1993.