DUBAI & Other UAE Emirates - The Geology In Dubai.

Dubai's area is 3,840 sq km. Oil in the four offshore fields is reservoired in Upper to Lower Cretaceous formations, mostly in Ilam, Mishrif, and Thamama carbonates.

In the Margham area onshore, substantial reserves of gas and condensates were found in Lower Cretaceous Thamama carbonates similar to those in the neighbouring Sajaa field of Sharjah (see Gas Market Trends). A test of the Triassic at Margham by Arco Dubai has not yielded a promising result.

Fateh, found in June 1966, was Conoco's first offshore discovery in Dubai and the company called it a giant. At the time Conoco estimated Fateh oil in place at 2.9-5.8 bn barrels. The field, 15X8 km, has been on stream since 1969. It has 39o API oil with 1.4% sulphur in the Upper Cretaceous (UC) Ilam formation, a less sour 39o oil in the MC Mishrif, and a more sour 31o oil in the LC Thamama. A Permian Khuff and pre-Khuff test at the field in 1980 encountered very sour gas.

Fateh production reached a peak of 190,000 b/d in Oct. 1990. Now it is about 80,000 b/d, compared to 150,000 b/d in late 1995. An EOR system based on water injection into the Mishrif since 1975 has been complemented by secondary EOR efforts. But the field has been in decline and its reserves are depleting, as in the case of the other three fields. In April 1993 Conoco began a pilot plan in the Mishrif based on miscible gas injection. The results were not as good as the firm expected. Production costs at the field exceed the $4/barrel figure estimated in late 1995.

Gas injection units covering all the formations would be very expensive. Together with the proposed purchase of (and investment in) gas from Iran or from Qatar, such a programme could bring production costs at the field to about $8/barrel. Additional EOR investment in the three other fields will be required as well. To justify the investment, Conoco has been negotiating with the Dubai Petroleum Department since 1993 for improved terms and incentives. But no agreement has been reached so far.

TotalFinaElf has had an agreement with the local government to sell about 70 MCF/day of associated gas from Iran's offshore Sirri fields which the French company has developed, with the gas to be delivered to the Jebel Ali free zone. But the deal is frozen as the US has been opposed to it.

South-West Fateh was discovered in Nov. 1970 about 10 km SW of Fateh and was similar in size, with Conoco then estimating its oil in place at 1.1-2.4 bn barrels. The field went on stream in 1972. It produces 32o API oil with 1.3% sulphur from Mishrif and Thamama carbonates. A Mishrif water flooding system started in 1974 is no longer sufficient to arrest a steady decline in production, which has fallen from 191,000 b/d in 1979 to 170,000 b/d in the 1980s but yielded more than 180,000 b/d in October 1990. The field needs a more advanced EOR system, as its current output is averaging about less than 64,000 b/d, from 127,000 b/d in 1995.

Rashid, found in Dec. 1973 about 24 km south of Fateh with oil in place at the time estimated at 114m barrels, is a small field. It has 37-41o API oil in the LC Thamama and 53o API condensate in the MC Mishrif. The latter formation also has a small accumulation of natural gas. Production is averaging about 1,000 b/d, from almost 1,500 b/d in late 1995.

Falah, found in Aug. 1976 some 23 km from Fateh and on the median line with Iran, is about 18x7 km. Conoco at the time estimated its reserve at 524m barrels. The field has 25.5o API oil and some 47o oil in the MC Mishrif. It went on stream in 1978. In 1979 the field produced more than 8,600 b/d. Now it is producing about 6,000 b/d.

Conoco signed a $900m deal with Iran's NIOC in March 1995 to develop the two Sirri fields - which are close to its four Dubai fields and are rich in gas. One aim was to get the gas to be reinjected into its four fields. But after pressure by the Jewish lobby, the company's then parent Dupont and the Clinton administration forced Conoco to withdraw from that deal. Total took its place and in mid-July 1995 signed a $600m deal with NIOC. The US tried but failed to get Total to withdraw from the deal.

Margham, an onshore gas/condensate field now operated by state-owned Dubai Margham Establishment, was found by Arco in 1982 at the edge of the Oman mountains' over-thrust belt. It went on stream in 1984 and in 1985 its output averaged 25,800 b/d of 50o condensates, freed of wet gas, and over 450 MCF/day of gas from Lower Cretaceous Thamama carbonates. The field is north of Margham town and is about 45 km from Dubai City. In 1982, Margham's recoverable gas reserves were estimated at more than 3 TCF. The reserves of condensates have been estimated at 30-32m barrels.

The condensate stream has been stabilised at about 20,000 b/d since 1997, having fallen to 15,000 b/d in 1991. There are wells to recycle dry gas after the condensate is extracted, enabling it to be conserved for future use instead of being flared, plus a production and gathering system. The field has a reinjection system with a 150 MCF/day capacity.

A 10-inch pipeline carries condensate to Jebel Ali. Another pipeline carries the gas to Jebel Ali. The first phase of the pipeline from the field to Jebel Ali, 150 MCF/day, was completed in 1989 when Arco began supplying the gas to the free zone. The second phase which raised the capacity to 450 MCF/day was completed in 1993.