Overview of Country and Country Permits
Tunisia like many North African countries currently can be considered to remain underexplored with regards to hydrocarbon resources, with prospects for attractive opportunities for both exploration and production. The country maintains a fair and equitable hydrocarbons agreement and by choosing the correct permits this can result in both low capital expenditure and operational expenditure.
Circle Oil Tunisia Ltd (a wholly owned subsidiary of Circle Oil Plc.) holds interests in three permits in Tunisia.
Grombalia permit
The first, the Grombalia permit, covers an area of 2,792 sq.kms and has a proven petroleum system with the Tertiary Bou Dabbous and/or Cenomanian Bahloul limestones and Fadhene shales as source rock and the fractured Bou Dabbous and Campanian Abboid limestones as reservoirs. These have proven historically to be good for production within structurally controlled faulted closures.
In addition within the permit area there is a shallow water area located just offshore in the Gulf of Tunis in around 15m of water. This area contains a large anticline elongated north east-south west, and is fault bounded parallel to the coast. The main reservoir objective is the Eocene fractured limestones of the Bou Dabbous formation. This prospect is also located in an ideal position to receive any hydrocarbon generated in the Grombalia graben to the south and west, which is considered as the main kitchen in the area.
Circle Oil Tunisia holds a 15% working interest in the permit and is presently increasing its working interest to 35%. The operator and partner is Exxoil Ltd a local Tunisian company.
Ras Marmour permit
The second permit, Ras Marmour, is located in the south-east of Tunisia covering part of the Ile de Djerba and south of the Gulf of Gabès. The permit covers 1,564 sq km and is located in an area with two significant hydrocarbon discoveries and a number of smaller ones. These include the onshore Ezzaouia oil and gas field discovered by Marathon in 1986 and the offshore El Biban oil and gas field, also discovered by Marathon in 1982. Other discoveries include the Robbana field which was discovered by Marathon and Mazran field, discovered by HBS.
The main reservoir types in this permit include fractured dolomites of the Cenomanian Zebbag formation, which form the main reservoir of the Ezzaouia field and fractured limestones of the Bireno formation of Middle to Lower Turonian age, which form the main reservoir of the El Biban field. In addition the Upper Jurassic sands levels of the M'rabtine formation are productive in the Ezzaouia field.
The source rocks in the area are platey black shales of the Lower Cretaceous (Cenomanian-Albian) which has proved the source rock of the Upper and Middle Cretaceous reservoirs of El Biban and Ezzaouia fields respectively and Lower Cretaceous age Sidi Kralif shales formation which form the source of both Robbana and Mazran fields. In addition the Marls and the black clayey limestones of the Middle Jurassic (Dogger) which source the Upper Jurassic sandstone reservoirs (M’rabtine formation) are productive in the Ezzaouia and El Biban fields.
Circle Oil Tunisia holds a 23% working interest in the permit. The operator and partner is Exxoil Ltd a local Tunisian company.
Mahdia permit
The third permit Mahdia is offshore and this permit covers an area of 3,780 sq.km and is bounded by the Nabeul Permit to the north and the territorial boundary with the island of Lampedusa to the east. Historically the geology and potential of this and the surrounding offshore area was successfully explored by Shell and Total and previous exploration has resulted in discoveries particularly within the Birsa Sands and commercial oilfields including fields such as Tazerka, Birsa, Oudna, Halk El Menzel and Isis.