THE PROVENCAL BASIN: HC POTENTIALS IN AN UN-EXPLORED RIFTING BASIN
The “Provençal Basin”, portion of the sea that lies between the southeastern coasts of Spain and France, the east of Menorca Island and the western coasts of Sardinia and Corsica, has proved to be an attractive area with a significant potential for hydrocarbon generation.
This potential is linked to the unique tectonic arrangement and the occurrence of salt related structures. All the essential geologic elements and geometries of reservoir-seal and overburden rocks that control the hydrocarbon generation, migration, entrapment and preservation may exist in the basin. Direct Hydrocarbon Indicators (DHIs) have been recognized on the seismic data (Roberts & Christoffersen, 2013) and the presence of possible seeps, occurring where the salt has either soled out or been broken up by diapirism, has been noted by some authors (Ianev et al., 2007).
Despite the fact that the Provençal Basin (province 4068) in World Energy 2000 Assessment study has been classified as a basin with a single hypothetical total petroleum system (Pre-Messinian TPS 406801) recent integrated studies using analogues, outcrop data and available seismic support the idea that at least 5 different petroleum plays can be identified in different zones of this large basin.
Three plays types are related to the post-rifting sequence, one is linked to the pre-Messinian clastic and carbonate units and the other two associated to different trap mechanisms in the post Messinian clastic units. The remaining two play types are associated respectively to the pre-rifting and the post-rifting sequence.
In the post rifting sequence reservoir types vary from pre-evaporite Oligocene-Miocene sandstones, Cretaceous fractured carbonates and deltaic sandstones, to post-evaporitic Pliocene-Pleistocene proximal to distal turbidites. Reservoirs in the pre-rifting sequence are mainly carbonate associated to the presence of the Mesozoic stable carbonate setting of the Tethys.
Examples of different source rocks intervals can be identified in the Mesozoic and Tertiary sequences outcropping in the surrounding areas in France and Italy. The characteristics of these source rocks vary according to the age and the depositional settings.
Recent basin modeling studies carried out on the Spanish part of the basin support the possibility of having multiple generations of HC from different source rocks if present in the basin.
The main reason for the lack of exploration in the past was related to deep water conditions (up to 2.6 km) a strong environmental sensitivity of the area. (Go to www.searchanddiscovery.com to see figures.)
AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015