ABU DHABI - ADCO's Operations.

Murban-Bab - now known as Bab - was the first oilfield in Abu Dhabi discovered in 1954 by PD/TC. It went on stream in 1964, after long delays. Bab is a giant oilfield rich in natural gas. Its oil production capacity was developed in the 1970s to more than 75,000 b/d. It was closed down in 1986 and re-opened in 1989. Its sustainable capacity rose from 60,000 b/d in 1989/90 to 100,000 b/d in early 1990. Because of the Gulf crisis, ADCO quickly raised its production to 150,000 b/d by early 1991. This was expanded to 250,000 b/d in 1993 and 300,000 b/d in June 1995 - the latter phase completed ahead of an end-1995 target. But the sustainable capacity by end-1998 had fallen to 250,000 b/d, though output was able to rise to 350,000 b/d for a short period of time.

Further expansion raised Bab's long-term sustainable capacity by 150,000 b/d to 400,000 b/d at end-2004, but the actual output has recently been lower. With JGC Corp. of Japan having been the EPC contractor in a job worth about $92m, the expansion included the drilling of more wells, injection of carbon dioxide into the field's Thamama B reservoir, supply and installation of two processing trains, two- and three-phase separators, a degassing station and related pipeline work. The carbon dioxide is recovered from steam reformers and boilders at the Abu Dhabi Oil Refining Co. (Takreer) refinery in Ruwais and from the Ruwais Fertiliser Industries (Fertil) complex and pumped through a 120-km pipeline built to the Habshan gas processing centre under a related project. The Anchorage, Alaska, based Canadian company Veco was the project management contractor (PMC), and the front-end engineering and designs (FEED) work was done by Technip-Coflexip. As part of the expansion, gas re-injection into Bab increased by 46% to 450 MCF/d - this being in addition to EOR systems already installed at the field (see background in Vols. 56 and 60, No. 2).

In another project handled by Gasco, the pneumatic systems as Bab and Asab will be replaced by a distributed control facility called Integrated Control System (ICS). Bab is a major gas producer (see following pages).

At North-East Bab and Bu Hasa fields gas injection compressors and related long-lead items have been supplied by Dresser Engineering and Mitsubishi under a $50m contract.

Located about 85 km south-west of Abu Dhabi City, Bab occupies an area of around 1,200 sq km. It has more than 10 oil and gas bearing zones, mainly in Thamama formations (Fms), at depths ranging from 88 to 12,000 feet. The oil is of the Murban group, as in the case of ADCO's Bu Hasa, Asab, Shah and Sahil. Bab has over 460 wells, including more than 130 oil producers in the upper oil zone, 20 gas producers in the upper gas zones and seven wells in the lower gas zones. The Murban blend, from ADCO's fields, is exported through the Jebel Dhanna oil terminal which has been expanded. An 18-inch, 126.5-km crude oil pipeline built from Bab to an oil refinery on Umm Al Nar island was completed in 2003 a $50m project which replaced old oil and water pipelines.

Bu Hasa, found in 1962, is ADCO's biggest oilfield. It has been expanded from 400,000 to 600,000 b/d, under a gas injection programme for both Bu Hasa and Sahil fields. But this capacity is not sustainable and the field has produced at the rate of 100,000 b/d for years in view of OPEC quota limitations.

A $350m project is expanding the field's long-term sustainable capacity to more than 650,000 b/d by end-2005. The project includes supply and installation of a 730,000 b/d degassing plant; replacement of existing two-phase 50,000 b/d gas separators with four new three-phase ones each of 120,000 b/d capacity; and re-injection into the field's G,F and D reservoirs of 95 MCF/d of gas and 120,000 b/d of water. The $318m EPC contractor for this is Snamprogetti which signed the deal with ADCO in August 2003, with Parsons Int'l of the US providing PMC services. The new EOR system is necessary and challenging, as the water content at Bu Hasa in early 2003 was expected to rise above 30% within five years. The water cut has reduced reservoir pressure. In a related project, four units and Bu Hasa's instrumentation and control system are being upgraded.

For its part, Gasco in 2003 contracted Larsen & Toubro which is upgrading and modifying the gas-gathering facilities and related installations at Bu Hasa. This should also handle up to 65 MCF/d of additional gas as from next April. Technip-Coflexip did the FEED work.

Huwaila, a small satellite field just south of Bu Hasa, is being developed to a sustainable capacity of 10,000 b/d from late 2005. VECO has done the FEED work and has the detailed engineering and procurement contract. A tender for construction work was done in August 2004. Crude oil from the field will be transported to Bu Hasa by pipeline.

Asab, discovered in 1965, is ADCO's second biggest oilfield, but its sustainable production capacity is limited to 200,000 b/d. The field is capable of 400,000 b/d peak production. ADCO is raising its long-term sustainable capacity to 220,000 b/d by late 2006. Asab is rich in natural gas. VECO last month won a $40m EPC contract for the Asab water injection project. The 29-month contract calls for construction of a new 23-cluster system, aimed at improving reservoir pressure at the field. VECO did the FEED work on the project.

Shah, found in 1966 but developed in 1990/91, now has a sustainable capacity of 65,000 b/d. This is being expanded to reach 80,000 b/d in 2006. Sahil, discovered in 1967 and developed in 1990/91, has a sustainable capacity of 65,000 b/d which should reach 75,000 b/d in early 2006. Sahil crude oil is processed at a central facility at Asab which has a spare capacity of 80,000 b/d.

All these fields have gas-rich Arab and Thamama Fms, the basis of a major onshore gas development programme. They provide gas to local power plants and Gasco at Ruwais.

ADCO's north-east Abu Dhabi (NEAD) oilfields, Rumaitha (found in 1969), Al-Dabb'iya (1970s), and their satellite Shanayel (1983), came on stream in 2000 at a combined capacity of 10,000 b/d producing from 10 wells. They are being developed to a sustainable long-term capacity of 150,000 b/d and a plateau of 200,000 b/d - mostly from Al-Dabb'iya - by mid-2006. Their current output is being supplied to the Umm Al Nar oil refinery. Their expansion is to cost almost $600m.

With VECO providing PMC services and Technip-Coflexip having done the FEED work, the $566 EPC contract was awarded in April 2003 to a partnership of Technip and Abu Dhabi's National Petroleum Construction Co. (NPCC). The EPC contract covers supply and installation of two oil processing trains, in-field pipeline works, installation of a pipeline to carry the crude oil to the Habshan processing centre and related facilities. A related project involves supply of 10 gas injection compressors (see reference to these fields in OMT).

Jarn Yaphour, discovered in 1973, was only developed in 1992/93 because it was one of the most complex fields in the industry. It is the nearest field to Abu Dhabi City, just 35 km to the south-east. It went on stream in November 1993 with a capacity of 3,000 b/d later expanded to 10,000 b/d. It produces from two wells, supplying the Umm Al Nar refinery. Another 10 wells completed in 1994 are producing 60 MCF/d of gas. Sweetened gas is supplied to a local power plant.