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Flare practice & improvement on Gullfaks oil field. Magne BJØRKHAUG Ph.D. Adviser, Process safety, Statoil. Statoil operations in the North sea. 60 % of the produced oil and gas is operated by Statoil
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Flare practice & improvementon Gullfaks oil field Magne BJØRKHAUG Ph.D. Adviser, Process safety, Statoil
Statoil operations in the North sea • 60 % of the produced oil and gas is operated by Statoil • Gas and oil is transported through extensive pipelinesystem or through offshoretanker loading of oil • Most new installations andsome of the old ones haveinstalled the flare gas recovery system
New flare practice on Gullfaks oil field • One production mode - Two flare modes Open and ignited flare Closed flare system
Basic elements in the new flare system • High integrity flare opening valve • Flare gas recovery system • Flare ignition system • High quality safety system
Basic elements in the new flare system Bursting Disc To the flare stack with ignition system LO LO HH HH PT PT HIPPS FOV XV Flare gas recovery system Sources HP K.O. Drum
Ignition unit on Gullfaks C Ignition unit
Flare practice & improvement • Environmental and economical improvements • Reduces CO2 emission to the atmosphere • Save CO2 tax • Increase gas utilisation • Increase the lifetime of the flare tip • Reduces the need for purge gas in the flare system
Flare practice & improvement • Operational improvement to achieve the results • A proper designed plant control system • A proper planned plant maintenance system • Recovery of gas from depressurisation of equipment • Recovery of blanket gas
200 000 150 000 100 000 Volume: Sm3/d 50 000 0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year Flare practice & improvement • Avg. flare per year - Gullfaks C
Flare practice & improvement • Gullfaks C - Daily flare volume 2005 900 800 700 600 3 500 1000 Sm 400 300 200 100 0 01.12.2005 01.05.2005 01.06.2005 01.07.2005 01.08.2005 01.09.2005 01.11.2005 01.01.2005 01.02.2005 01.03.2005 01.04.2005 01.10.2005
Flare practice & improvement • Gullfaks C - Daily flare volume 2005 900 800 700 600 3 500 1000 Sm 400 300 200 100 0 01.12.2005 01.05.2005 01.06.2005 01.07.2005 01.08.2005 01.09.2005 01.11.2005 01.01.2005 01.02.2005 01.03.2005 01.04.2005 01.10.2005 A continues flare load of App. 50.000 m3/day is added at the bottom
Estimates of reduced flaring • Total flaring 2005 for Gullfaks C: 26 656 m3/day • Continues basic load: App. 50 000 m3/day • Estimated total flare load: App. 75 000 m3/day • Estimated reduction for Gullfaks C in 2005: 60-70 % Average reduction in yearly flaring du to the “no-flare” technology is approximately 50% on Gullfaks during normal operation
Flare practice & improvement • Gullfaks flare system 12 years after: • The system have been operated without any • major problem for the operation time of 12 years. • The systems have been rebuilt to increase the capacity • due to tie-in of satellite fields. • Described in 1997 version of API 521. • Total savings in 12 years has been in the order of $ 200 mill.