Anne K. Rhodes
Refining/Petrochemical Editor
World marker crude Brent blend was as sayed in August 1994. The price of this 38 API, 0.04 wt % crude from the U.K. North Sea is used to determine the prices of many other world crudes.
The assay was supplied by Enterprise Oil plc, London. Brent's distillation curve is shown in Fig. 1 (7688 bytes).
Brent's qualities have changed since an assay of the crude was last published in the journal, at which time the stream recently had been commingled with Ninian blend (July 8, 1991, p. 46). API gravity has increased by only 0.5 and sulfur content, by 0.05 wt %, but the crude's pour point has decreased from -12 C. to - 42 C.
Brent blend comprises Brent, North and South Cormorant, Tern, Eider, Dunlin, Osprey, Murchison, Thistle, Deveron, Don, Hutton, N.W. Hutton, Ninian, Heather, Magnus, North Alwyn, Lyell, Staffa, and Strathspey fields. Lyell, Staffa, and Strathspey use some of Ninian's spare processing capacity. These fields have been added to the blend since an assay was last published.
Oil from Shell-Esso's Pelican field is scheduled to be added to the stream at the Cormorant Alpha platform beginning in late 1995. And as of last November, Total expected to bring its Dunbar field on line via the Alwyn North platform by the end of the year (OGJ, Nov. 14, 1994, p. 31).
Some say Brent's future as a world marker crude is in jeopardy, as Brent fields are in decline and BP's lease at the Sullom Voe terminal, in the Shetland Islands north of Scotland, expires in the year 2000. In fact, Shell Exploration & Production has begun a program to redevelop Brent for gas production, although this will recover additional crude as well.
According to Oil & Gas Journal records, Brent production in 1994 averaged about 815,000 b/d. That rate has been projected to decline to anywhere from 450,000 , b/d to as low as 300,000 b/d over the next 4-5 years, as the fields that feed the Ninian and Brent systems decline.
BP's Foinaven field is set to be the first producer West of the Shetland Islands. In a recent test, a Foinaven well flowed 17,800 b/d of waxy, 26 API oil for some 6 weeks (OGJ, Oct. 31, 1994, p. 26). Foinaven will be produced using a floating storage, production, and offloading unit beginning in late 1995 or early 1996.
If the volume from such "West of Shetlands" developments becomes sufficient, the streams may be transported to Sullom Voe via pipeline in the longer term. This may breathe new life into the aging Brent system.
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