ABSTRACT: Rospo Mare (Adriatic Sea)--An Oil-Bearing Paleokarst in the Mediterranean Region

Henri-Jean Soudet, Patrick Sorriaux, Frederique Michaud

The oil-bearing paleokarst at Rospo Mare is located in the Adriatic Sea, 20 km off the Italian coast. The reservoir lies at a depth of 1300 m and consists of a paleokarst of Oligocene to Miocene age that developed within Cretaceous limestones, now covered by 1200 m of Miocene-Pliocene clastics. The oil column is about 140 m.

The karstic nature of the reservoir was identified through vertical cored drill holes, which allowed us to analyze the various solution features and the sedimentary infill (speleothems, terra rossa, marine clays), as well as their vertical distribution.

Observations concerning the upper part of the reservoir were compared to a paleokarst of the same age, outcropping widely onshore, in quarries located nearby.

Erosion morphology at the top of the karst is highly irregular, including especially paleovalleys as well as many pit-shaped sink holes. Detailed knowledge of that morphology through geophysics helped optimizing the development of the field through horizontal drilling.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990