LIBYA - The Fields.

There are 12 oilfields in Libya with reserves of more than 1 bn barrels in each. The fields of NOC are mainly in the Sirte Basin, the most prolific oil province covering the north-central and north-eastern parts of Libya. There are another two fields with 500m to 1 bn barrels each.

NOC holds 51% in North African Geophysical Exploration Co. which started up in August 1988 and does extensive work. The 49% partner is Western Geophysical Co. (WGC) of Calgary, a unit of Dresser Atlas Co. of Houston.

An important unit at NOC, the National EOR Committee formed in 1981, assesses the full potential of Libya's oilfields and oversees EOR projects. The first EOR system in Libya was installed in 1969 at the Intisar D field.

Arabian Gulf Oil Co: Agoco is the biggest oil producer formed by NOC in late 1979 to take over the assets of a partnership of BP and Nelson Bunker Hunt of the US, and a partnership of Chevron and Texaco called Amoseas. Its largest fields are Sarir and Nafoora, which together produce less than 250,000 b/d from 490,000 b/d in 1995. Agoco now has the capacity to produce 380,000 b/d, which it intends to expand to 450,000 b/d within the coming three years.

Agoco has a refinery at Tobruk on stream since 1985 with a capacity of 18,000 b/d, where in 1996 it had two thermo compression distillation units installed to produce 750 CM/day of drinking water from the sea. Agoco also has a 9,000 b/d topping plant at Sarir.

Sarir was found in 1961 by BP at a depth of 9,000 feet in an Upper Cretaceous formation (Fm). This, in the south-east of the Sirte Basin, marked the beginning of a rapid expansion of E&P activities in the Sirte Basin by foreign firms. In the subsequent years, the field proved to be a super-giant with a recoverable reserve of about 7.5 bn barrels. It was followed by Sarir North and a smaller field (L-65) about 19.2 km to the north-west.

Sarir's planned expansion to a sustainable capacity of 600,000 b/d, through a massive EOR system, is not likely to be attained in the near future. A limited water injection system installed in 1995 to raise its capacity has since proved to be ineffective. Sarir's capacity is less than 200,000 b/d, from 250,000 b/d in 1992. Sarir's 37.2[degrees] API oil is very waxy. The crude is pumped via a 400-km pipeline to the Marsa El-Hariga terminal.

BP and Hunt each had 50% in the field. BP's assets were the first to be nationalised in September 1971, with Col. Qadhafi having taken power on Sept. 1, 1969. NOC acquired Hunt's 50% in July 1973.

Nafoora and Augila are in the north-east of the Sirte Basin. Nafoora was found in 1966 and Augila in 1967 by BP. Both have waxy 35.5[degrees] API oil. They lie at depths of 2,200-10,000 ft. A gas lift system was installed at Nafoora as part of an EOR project, which has enabled the fields' capacity to be maintained at 100,000 b/d. The gas is treated at a plant in Agip's Bu Attifel field. Of 15 wells at Nafoora, 13 are producers.

Kebir was found in the late 1980s by Agoco in Block NC 7 in the Ghadames Basin near the Tunisian border. It contains light/sweet oil. Along with Murzuk field, which contains light/sweet oil, Kebir has been slated for development since 1991. But Agoco has rejected bids made by foreign companies (see Vol. 57, No. 2).