ABU DHABI - ADCO's Operations & Oilfields.

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 250,000 b/d, though output can peak at 350,000 b/d for a short period of time.

Work on a further expansion, in a $250m project, will raise Bab's long-term sustainable capacity by 100,000 b/d to 350,000 b/d by end-2004. The project will include the drilling of more wells, injection of 100 MCF/d of carbon dioxide into its 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 will be 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 to be built to the Habshan gas processing centre under a related project.

JGC Corp. of Japan in late 2002 was recommended for the award of the main engineering, procurement and construction (EPC) contract for the expansion project as it was the low bidder at $92m. The project's front-end engineering and design (FEED) work was done by Technip-Coflexip of France. The Anchorage, Alaska, based VECO is the project management consultant (PMC). As part of the expansion, gas re-injection into Bab will be increased by 40% to 400 MCF/d - this being in addition to EOR systems already installed at the field (see background in Vol. 56, No. 2). In another project being handled by Gasco, the existing pneumatic systems as Bab and Asab will be replaced by a distributed control facility called Integrated Control System (ICS). Bids for a FEED contract for this were being evaluated in late 2002. Bab is a major gas producer (see following pages).

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, 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 400 wells, including 128 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 is being built from Bab to an oil refinery on Umm Al Nar island which will be completed this year. This is under a $50m project to replace 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 been producing at the rate of 100,000 b/d in view of OPEC quota limitations.

A new $300-350m project will expand the field's long-term sustainable capacity to 650,000 b/d by end-2005. The project will include 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. Technical bids for the EPC contract are due on Jan. 31, with Parsons Int'l of the US providing PMC services. The new EOR system is necessary, as well as challenging, as the water content at Bu Hasa is expected to rise above 30% in the next five years. The water cut has reduced reservoir pressure. In a related project, four units and Bu Hasa's instrumentation and control system will be upgraded.

For its part, Gasco has recently tendered a $20-25m EPC contract to upgrade and modify the gas-gathering facilities and related installations at Bu Hasa. This should also handle up to 65 MCF/d of additional gas. Technip-Coflexip did the FEED.

Huwaila, a small satellite field just south of Bu Hasa, is being developed to a sustainable capacity of 10,000 b/d by 2005.

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. Asab is rich in natural gas.

In a Gasco project, the existing pneumatic control systems at Asab and Bab are to be replaced by integrated control systems (ICS). Technical bids for the FEED contract were being evaluated in late 2002.

Shah, found in 1966 but developed in 1990/91, now has a sustainable capacity of 55,000 b/d. This is being expanded to reach 75,000 b/d before end-2005. Sahil, discovered in 1967 and developed in 1990/91, has a sustainable capacity of 55,000 b/d which should reach 75,000 b/d by 2005. 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 formations, 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 Dabbiya (1970s), and their satellite Shanayel (1983), went on stream in mid-1994 with a combined capacity of 10,000 b/d from 10 wells to supply the Umm Al Nar oil refinery. In a $350-400m project, their sustainable production capacity is to be expanded to 150,000 b/d by 2005. The fields' peak production potential will be 180,000 b/d. With VECO providing PMC services, Technip-Coflexip has done the FEED. The EPC contract is to be awarded in 2003. This will cover supply and installation of two oil processing trains, in-field pipeline works, installation of a pipeline to carry crude to Habshan and related facilities. A related project involves supply of 10 gas injection compressors.

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.