Jeddi, R.S.1, P.F. Burollet2
(1) ETAP, Tunis, Tunisia
(2) CIFEG, France
ABSTRACT: The Miocene in the Gulf of Hammamet Basins - Tunisia - Stratigraphy, Sedimentology and Petroleum Targets
The Miocene sediments in the Gulf of Hammamet are limestone, sandstone, shale, siltstone and gypsum. A large part of them is poor in or devoid of good stratigraphic fossil.
Sequence analyses in outcrops or in subsurface allowed the identification of nine to ten units limited by unconformities, including several gaps. They range from Aquitanian to Messinian ages. The sequences include deltaic deposits (off-shore bars, channels...) in connection with eustatic sea level changes and tectonic movements related to Alpine and Atlassic crises. The tectonic framework is guided by faults trending East-West, North-South or South-West - North-East.
Oil is associated with the Birsa and Lower Saouaf (Early Serravallian) good reservoirs (10 to 33% porosity); it is produced in some fields and has been recorded in the Zelfa and Baraka discovery wells.
An other reservoir is the Langhian Ain Grab Formation which consists in bioclastic limestone deposited in a shallow marine environment and has good petrophysical characteristics: 15 to 30% porosity, 150 md. of permeability.
The main source rocks in this area are : the Albian Fahdene black Shale, the Upper Cenomanian Bahloul Limestone and the Lower Eocene Bou Dabbous Limestone. Hydrocarbon generation and migration took place during the last 10 My.
The structural setting is characterized by horsts, grabens, synclines and folds resulting in structural and/or stratigraphic traps. Seismic interpretations revealed the presence of new prospects and leads which are attractive targets for future exploration.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.