But the project almost doubles the original capacity of the facilities: production first started in 2005 and peaked at 57,000 b/d of oil in 2009, and BP has raised hopes of further projects to maximize output from a field thought to hold over 7 billion barrels of oil.
BP on Friday highlighted its first ever use of an enhanced recovery technology it calls LoSal that involves injecting low-salinity water to maximize recovery levels, and said this could yield an additional 40 million barrels of production. Clair Ridge overall targets 640 million barrels of oil reserves.
BP on Friday described Clair Ridge as the largest North Sea installation project in more than 20 years.
Upstream chief executive Bernard Looney said the startup was the "culmination of decades of persistence."
"This is a major milestone for our upstream business and highlights BP's continued commitment to the North Sea region," he said in a statement.
Clair is a relatively heavy crude compared with others in the North Sea, with an API gravity of 23.2, and is shipped via pipeline for loading at Sullom Voe in the Shetland Islands.