LIBYA - The Ghadames Basin.
Early exploration by foreign companies in the Ghadames Basin resulted in small oil finds which were not developed, for lack of infrastructure. In the 1970s, NOC discovered several oilfields in the Hammadah Al Hamra plateau. Although they were small, the fields were close to one another and this warranted their development by NOC. The oil is reservoired in Palaeozoic sandstones.
Another petroliferous province has been established in the south-west of that region extending from the Palaeozoic Illizi Basin of Algeria. Oil is reservoired in Palaeozoic sandstones sourced from the same prolific Silurian shales which have contributed so much oil in North Africa. There are traps in that region which occur in folded and faulted structures, as in the case of the Hammada Al Hamra Basin to the north.
The Murzuk Basin: Separated from Ghadames by the Qarqaf uplift, the Murzuk Basin lies in a remote province formerly called Fezzan. It is about 800 km south-west of the Libyan coast. Early geological surveys there point to a strong possibility of reserves of up to 12,000m barrels of oil equivalent, of which 83% are likely to be gas. Al Sharara field there is a giant, found in 1985 by Rompetrol of Romania which then said its recoverable reserves were about 2 bn barrels. In late 1993, NOC said its recoverable reserve exceeded 5 bn barrels. The field, operated by Repsol/YPF, came on stream in late 1996 and will be producing up to 250,000 b/d eventually. Another Murzuk giant, Elephant field, was found in October 1997 by Lasmo of the UK and should be producing 150,000 b/d by 2004/05 (see Part 2).
Most Murzuk fields have a Palaeozoic reservoir similar to that of Illizi in Algeria. A northern extension was found in the 1980s by a Bulgarian firm but this failed to develop the structure because it lacked the funds and in 1996 its rights were sold to Canadian Occidental. The oil reserves there were originally estimated at about 600m barrels.
Repsol/YPF has made several important oil discoveries in Blocks NC-186 and NC-190 in this basin (See Repsol profile in Part 2).