SAUDI ARABIA - The Main Fields Producing Heavier Crudes.

Saudi Aramco's capacity to produce Arabian Medium and Heavy crudes has been limited to 1.2m b/d - 800,000 b/d for Medium and 400,000 b/d for Heavy - compared to about 4.87m b/d of installed capacity for these grades by late 1993. About 1.6m b/d of this installed capacity has been mothballed

There will be a further mothballing of field capacities producing heavy crudes as additional fields, including those in the Najd area south of Riyadh, come on stream.

Safaniyah: By far the largest offshore field in the world, Safaniyah was found in 1951 by Texaco (which in 1937 was the first to join SoCal - now Chevron - in Saudi Arabia as a 50% partner in Aramco). Texaco discovered and developed other offshore fields containing heavy oil. Safaniyah has about 19 bn barrels of proven oil reserves recoverable at relatively low cost. But the oil is heavy, 27 deg. API with 2.93-2.96% sulphur, and much of Safaniyah's 1.5m b/d capacity has been mothballed. Like most other offshore fields in the north-east, the oil is reservoired in Cretaceous sandstones and carbonates mainly at a depth of 5,100 feet. (Texaco, once a crude-long major now having become crude-short, sold 50% of its US East Coast system to Saudi Aramco in 1988. The resultant JV Star Enterprise made Texaco "crude-sufficient", at least in superstructural terms, as it gained a virtually permanent access to 630,000 b/d of Saudi crude oil). In 1996, Saudi Aramco brought some of the mothballed desalting units and other facilities at Safaniyah back into operation. They enabled the company to handle more Arab Medium crude from the offshore Zuluf field. Reservoir pressure at Safaniyah, however, is beginning to decline. Two rigs are working continuously there to prevent a fall in production.

Zuluf: Another offshore giant discovered by Texaco in 1968, Zuluf has 8 bn barrels of proven oil reserves in a Lower Cretaceous formation at a depth of 5,800 feet. Its capacity is over 500,000 b/d, with another 200,000 b/d and two GOSPs mothballed. Saudi Aramco has planned to raise the field's capacity to 1.2m b/d. Of this a further 500,000-700,000 b/d has been earmarked for closure. But related facilities to upgrade the field's production of heavy crudes to the Arabian Medium grade have been built.