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perry. us & ministry. aerial application of oil dispersant. (due to the large file size, a number of great pictures had to be removed from this presentation. We apologize.). present fleet. TURF & EYES : the story continues. pause. case study : Sea Empress. the Sea Empress incident :
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aerial application of oil dispersant (due to the large file size, a number of great pictures had to be removed from this presentation. We apologize.)
case study : Sea Empress the Sea Empress incident : dispersant spraying at its most effective Workshop on the application of dispersant in the Dutch part of the North Sea
The success of the spraying operation at the Sea Empress incident was due to a number of factors : - The primary ‘clean up’ response for dealing with oil spillage in UK waters was (and still is) aerial dispersant spraying, due to the length and nature of the coastline Legislation for the use of dispersantshad been in place for several years; the method and rules of approval had been well established, practised and refined during exercises and incidents So only local approval and confirmation was required success due to number of factors Equipment was readily available close at hand Personnel were an experienced & motivated team Size of the spill, location and type of oil were optimal Weather conditions were suitable for effective spraying
EQUIPMENT AND PERSONNEL equipment & personnel 1 Centrally-located surveillance and spray aircraft together with crews ( including engineers and ground loading teams) were available on permanent standby:30 minutes call during the day, and 2 hours at night Forward operating airfields near to the incident had been pre-identified Aircraft arrived at the forward base loaded with dispersant, and sufficient stock was stockpiled locally to enable operations to continue without delay
EQUIPMENT AND PERSONNEL equipment & personnel 2 Loading pumps and safety equipment were held permanently on the spray aircraft and functionally checked weekly Aircrew and ground support teams were well trained and practised – in addition to operations, drills were held monthly and deployment exercises twice a year Three main, centrally located, dispersant stockpiles were mobilised and the IBC tanks moved to the forward base
size & nature of spill 9 discrete oil spills over a period of 6 days Biggest was 20,000t and the smallest 2,000t Total spillage 72,000 tonnes of Forties blend crude and 360 tonnes of heavy fuel oil The oil was amenable to dispersant size of spill
LOCATION AND WEATHER location & weather Tanker ran aground at the entrance to the harbour Forward airfield was available close by Weather was mostly good for dispersant use : wind speed - more than 10 knots. sea state - breakers present (up to state 7/8)
strategy STRATEGY Because dispersant works more efficiently on freshly spilled oil and there were regular discharges from the tanker, the strategy was : Concentrate on freshly spilled oil first Spray ‘weathered’ oil later, if required STOP spraying when :- - sufficient dispersant applied - no longer effective due emulsification - slick too broken for effective spraying - weather unfavourably calm or too windy Monitor and spray again as necessary
SEA EMPRESS 70,000 tonnes spilled in total 37,000 tonnes (52%) of spilled crude oil DISPERSED 10,000 tonnes NATURALLY 27,000 tonnes AFTER AERIAL DISPERSANT APPLICATION oil stats +PO spraying
general guidelines & SOPs general guidelines and operating procedures for spraying operations Workshop on the application of dispersant in the Dutch part of the North Sea
Control & Guidance From start to finish, control of spraying is under the guidance and direction of the surveillance aircraft, usingstandard operating procedures. control & guidance
safety of airspace safety of airspace The surveillance crew and dispersant spraying team initially determine the dimensions of the ‘safe’ operating area Control over the ‘safe’ area is established by national emergency controlling authorities requesting restrictions over the airspace and sea area Ideally the operating area should be kept completely clear of all other aircraft, vessels and obstructions All spray operations are strictly daylight VFR For example in the UK, the Secretary of State is enabled through an act of parliament to declare a ‘temporary exclusion zone’ (TEZ) around a ship or structure at sea The National Air Traffic Services have the authority to establish a temporary danger area (TDA) to restrict flying All aircraft movements within the TEZ and TDA are controlled by the surveillance aircraft crew
Initial role of surveillance aircraft crew Establish, survey and control the ‘safe’ operating area Obtain & confirm approval to use dispersant Confirm dispersant type Confirm geographic & water depth constraints Locate position of thickest oil Determine ‘spray’ pattern Brief, guide & direct the test spray Assess and report the effectiveness of test spray initial role of surveillance crew
efficientapplication efficient application The surveillance aircraft crew determine position of the thick oil within the slick either visually (seen astrue colour, discontinuous true colour, or metallic appearance) or using the IR detector. The spray pattern is then oriented to ensure that the dispersant is applied only to the thick oil, not sheens. Visual observation can confirm the dispersant is working. The oil will spread rapidly and there will be a ‘milky’ plume mainly at the edges.
Application Dispersant is delivered by aircraft fitted with approved spray systems. Aircraft normally fly into windat low level,20-50 feet above the surface, at about140 knots, depending on aircraft type Normal dose rate 1 t of dispersant to 10 / 20 t of oil application
spray pattern spray pattern SPRAY CIRCUIT WIND SPRAY ‘OFF’ CLIMB STRAIGHT AHEAD TO 300 FEET THICK OIL SPRAY ‘ON’ LEVEL AT 30 FEET CIRCUIT HEIGHT 300 FEET SHEEN SPRAY AIRCRAFT SURVEILLANCE AIRCRAFT (700 FT – 1000 FEET)
Effectiveness effectiveness After the spray aircraft has cleared the area the dispersant monitoring vessel is called in by the surveillance aircraft. Data is collected in clear water, the sprayed area, and the oiled area, using UV fluorescence spectroscopy. Data is analysed and the results passed back to the surveillance aircraft DISPERSANT MONITORING VESSEL’S TRACK AREA SPRAYED THICKOIL If the results are positive i.e. the dispersant is working – spraying continues and monitoring takes place at regular intervals between deliveries SHEEN If the dispersant monitoring team are not available, the dispersant effectiveness is assessed visually by the surveillance crew and passed to the response authorities SURVEILLANCE AIRCRAFT
role of surveillance aircraft crew during main spraying operations main role of surveillance crew Brief & direct the spray aircraft in the pattern Direct the in-situ monitoring vessel Monitor the area and spill between spray applications Stop spraying when sufficient dispersant has been delivered or as required by the response authorities
‘DANK U WEL’ THANK YOU questions QUESTIONS ?