The system was first used in 1979 for British Hydrocarbons in the English Channel , it has since evolved into what it is today. Over the 36 years it has undergone constant improvement in terms of materials and attachment methodology.

The strake system comprises discrete lengths of a specially designed extrusion with a Stainless Steel (316) core. The configuration is a 3 start helix with a pitch of between 10 and 15 diameters per revolution. The stand up height is a nominal 10% for the standard system. Typical ASRs (amplitude suppression ratios ) are 79/80% for this configuration.

Higher stand up height can give a higher suppression ratio but always has a drag penalty which is proportional to the frontal area presented to the current. It is a balance between the two and analysis will determine the requirements that are more important in each case. Pitch can also effect the drag and suppression performance.

The current method of attachment is by banding, this can be either a 316 stainless band or for more permanent installations a hybrid glass reinforced band is available (HCL Fasteners) which some customers have specified.

The Allbrown strake system has a long track record when applied to the offshore drilling industry – as you can see from our Client List

One of the features of the latest system is that it does not slip as the circumferential pressures applied by the banding are only applied at the strake stand up point and not spread over the whole diameter which has enabled the system to survive the forces applied whilst being driven (piled). The track record speaks for itself from large diameters on buoyant drilling risers to small diameter completion risers.

Track record for Strakes

1979 British Gas English Channel Drilling Riser – Jack-up
1982 S.N.E.A.P English Channel Drilling Riser – Jack-up
1983 Conoco English Channel Drilling Riser – Jack-up
1983 Union Oil English Channel Drilling Riser – Jack-up
1984 Esso Exploration English Channel Drilling Riser – Jack-up
1984 Texas Gas English Channel Drilling Riser – Jack-up
1984 British Gas Cardigan Bay Drilling Riser – Jack-up
1985 BP North Sea Buchan Structural Member
1985 BP North Sea
1988 Union Oil Offshore Kenya Drilling Riser – Drillship
1988 Camco Wireline Lubricator Assy
1988 Marathon Cook Inlet Alaska Drilling Riser – SemiSub
1988 Geocean English Channel Coring Casing – Jack-up
1988 Occidental English Channel Drilling Riser – Jack-up
1990 B.H.R. Group Evaluation & Testing / BP
1990 BP St George’s Channel Drilling Riser – Jack-up
1990 Arco Cook Inlet Alaska Drilling Riser – Jack-up
1991 Occidental English Channel Drilling Riser – Jack-up
1991 Camco Wireline Lubricator Assy
1991 Arco Cook Inlet Alaska Drilling Riser – Jack-up
1991 Arco Cook Inlet Alaska Drilling Riser – Jack-up
1992 Arco Cook Inlet Alaska Drilling Riser – Jack-up
1992 Sun Oil Malaysia S.E Asia Sabah Drilling Riser – Jack-up
1992 Chevron Alba Jacket Structural members
1992 Shell Oil Nelson Jacket Structural members
1992 S.T.C Sea of Japan Large dia Comms Cable
1993 Elf Enterprise English Channel Drilling Riser – Jack-up
1994 Marathon Oil St George’s Channel Drilling Riser – Jack-up
1995 Marathon Oil Irish Sea Drilling Riser – Jack-up

Track record for Strakes (cont.)

1995 Shell Norge Norway Glycol injection lines
1996 Marathon Oil Isle of Man Drilling Riser – Jack-up
1996 Petrobras Brazil Deepwater Uptake Riser
1996/7 BP G.O.M, Troika Buoyant Drilling Riser Semi
1997 Statoil North Sea Gulfax Satellite pipelines
2001 BHP Petroleum English Channel Drilling Riser – Jack-up
2002 Global SantaFe Morecambe Bay Drilling Riser
2002 Global SantaFe Morecambe Bay Completion Riser
2003 Global SantaFe Southern North Sea Drilling Riser
2003 Global SantaFe Drilling Riser
2004 Tullow Oil Gabon Drilling Riser – Jack-up
2004 Centrica Southern North Sea Completion Riser
2005 BP Sakhalin Project Drilling Riser – Semi Sub
2005 Burlington Re Morecambe Bay Completion Riser
2005 Marathon Oil St George’s Channel 20 inch bare Riser
2005 Caledonia Oil & Gas Southern N. Sea 7 Inch Completion Riser
2005 Caledonia Oil & Gas Southern N. Sea 7 Inch Completion Riser
2005 Vetco Gray Southern N. Sea 7 Inch Completion Riser
2006 EOG Resources Offshore Trinidad 20 Inch drilling Riser
2006 Gaz de France Southern N.Sea 7 Inch Completion Riser
2006 BP Gulf of Mexico Experimental Strake - special
2007 Gaz de France Southern N. Sea 7 inch completion Riser
2007 Perenco Southern N.Sea 7 inch Completion Riser
2007 Vetco Gray Southern N.Sea 16 inch Riser
2007 Foxtrot Int Côte d’Ivoire 30 inch Drilling Riser
2007 ENI/Vetco Egypt 30 inch Drilling Riser
2007 ENI/Vetco Egypt 7 inch Completion Riser
2007 GlobalSantaFe Southern N.Sea 30 inch Drilling Riser
2007 GlobalSantaFe Southern N.Sea 7 inch Completion Riser
2007 Eon Ruhrgas Southern N. Sea 7 inch Completion Riser
2008 GlobalSantaFe Southern N. Sea 30 inch drilling riser
2008 Vetco/ GE Southern N.Sea Drilling Riser
2008 Tullow Oil Ghana 30 inch drilling Riser
2008 Repsol Brazil 20 inch bare drilling riser
2009 Centrica Southern N. Sea 7 inch completion riser
2009 Centrica Southern N.Sea 7 inch completion riser
2009 Foxtrot Int Côte d’Ivoire
2009 EOG Irish Sea/ IOM 30 inch Drilling Riser
2009 ENI/ Vetco 20 inch Drilling Riser
2010 Repsol Brasil Brazil 7 inch Completion Riser
2010 RWE 30 inch drilling riser 20 inch deepwater bare riser
2010 Fraser Offshore Southern N.Sea 24 inch drilling riser
2010 Foxtrot Int Côte D’Ivoire 30 inch drilling risers
2010 Fraser Offshore North Sea 7 inch completion riser
2010 RWE Southern N. Sea 30 inch drilling risers
2011 ADTI Southern N.Sea 30 inch drilling riser
2011 Tullow Oil North Sea 30 inch drilling riser
2011 Perenco North Sea 7 inch completion risers
2011 Tullow Oil Southern. Sea 30 inch drilling riser
2011 BP Vietnam 21 inch drilling riser
2012 Total W. Shetland 21 inch drilling riser
2012 Chevron North Sea Structural brace
2012 BP Indonesia 30 inch Drilling Riser
2013 EOG Resources Cardigan Bay 30 inch Drilling Riser
2013 Galoc Development Philippines Well Jumpers
2013/14 Total North Sea 21 inch Drilling Riser
2014 RWE North Sea 30 inch Drilling Riser
2014 Statoil Faroe Isles 21 inch Drilling Riser
2014 DF Suez North Sea 30 inch Drilling Riser
2015 Total North Atlantic 21 inch deepwater Riser
2019 Siccar Point Energy West of Shetland 1100m Semi submersible drilling riser
2024 BP Indonesia 30 inch conductor with very large pile driver