Rospo Mare Karstified Limestone Oil Field
Paul Andre, Alain Doulcet
The Rospo Mare oil field is located on a buried Lower Cretaceous regional high 20 km off the shore of the Italian Adriatic coast in the northeastern part of the Mesozoic Apulian platform. The operator is Elf Italiana SPA (61.67%) in a joint venture with Agip (38.33%).
The field was discovered in 1975. Four appraisal wells confirmed the reservoir extension and oil characteristics of the fields: highly fractured and karstified Albian to Cenomanian limestone at a depth of 1.350 m and 12° API specific gravity oil. The estimated accumulation is over 100 MT, and the field has an area of approximately 180 km2.
The trap is mainly due to a hydrodynamic tilt which is explained by the low contrast between the specific gravity of oil and water. For that reason the oil column ranges from 0 to 140 m from southwest to northeast. The oil source rock is believed to be Triassic.
In 1982, a pilot project, platform RSMA, was developed. This platform includes a horizontal well which was drilled to limit the waterflooding due to the lack of contrast between the specific gravity of oil and water and the low mobility ratio. Because of the good results of this well, a development program was based on the horizontal well technology.
A seismic 3D program was shot in 1984 over the central part of the field. The results showed with accuracy the details of a complex karstic morphology at the reservoir top.
In mid-1986 a development platform, RSMB, was set up, and four horizontal wells have been drilled with the help of the 3D seismic results.
AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.