Oil Spill Response Limited

Petroleum Association of JapanOil Spill Symposium 2001
David Salt
Technical Director
Oil Spill Response Limited
Developments in legislation and technological advancesin dispersant application in the United Kingdom
New Legislation
The United Kingdom adopted the International Convention on Oil Pollution
Preparedness Response and Co-operation,1990 ( OPRC) during 15th May 1998,
the statutory instruments to enact its powers were put in place on and the deadline
15th August 1999. As a result of the changes in legislation a number of new
requirements were placed on both Port operators and those working in the offshoreenvironment. This paper will particularly deal with the impact in respect of the oil spill
response requirements for offshore operators within the United Kingdom Continental
Shelf, (UKCS) and how the industry responded to them in a operationally effective
and cost efficient manner. It will also provide details of a number of developments inaerial spray technology, which are in the process of development within the UnitedKingdom.
UK Response Strategy
Aerial dispersant application has been a key response strategy for the United
Kingdom, the length of the coastline, intensity of marine traffic and typical prevailingsea conditions inhibit the effective use of containment and recovery systems.
Dispersant application from aircraft is therefore one of the most appropriate
strategies, provided that the local environmental conditions and the oil type aresuitable. The government has recently re-tendered its contract to provide the aerials
services and in the process has upgraded the capability to respond to oil spills usinglarger more modern aircraft. This has led to the development of a new spray systemthat is described in the second section of the presentation.
United Kingdom Offshore operations.
As part of the implementation of the OPRC convention, the United Kingdom
Department of Trade and Industry (DTI) reviewed the response requirements for
exploration and production operators in the UKCS. The Government was keen toprovide response guidelines to ensure that all operators maintained an appropriate
standard of response to cover offshore operations. These guidelines were expressedin terms of response capability and response time, dependant upon the nature of theoil and the nature of the environment in which the spill occurred. Details of therequirements are provided in Table 1 below :-Petroleum Association of JapanOil Spill Symposium 2001

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Table 1 Offshore Spill Response Times

Production Facilities, Development Wells and E & A Wells
Spill Quantity(Tonnes)

Seabird Vulnerability = Level 1

R1-Up to 25t
R2-Up to 100t
R3-Up to 500t
R4-Up to 10,000t

Oil Types
2, 3, 43, 4
2, 3, 42, 3, 4

Response Time
1 hour2 hours
6 hours
18 hours

All Other Offshore Environmental
Sensitivities
Oil Types
Response Time
No response requirement
3, 42 hours
2, 3, 4
6 hours
2, 3, 418 hours

Response times
The response levels and times based on an assessment of the size of the spill, thenature of the environment and the persistence of the type of oil involved. The mostcritical response level, R1, is aimed at dealing with a small (25T) spill of persistent oilin a high vulnerability area. The typical response requirement, R2, is generally
provided by dispersants placed offshore. The key problem area arises at the R3
response level, it is this level that the new aerial provisions were targeted. R4 wasprovided for by the use of the Hercules and ADDs pack system.
Oil Type
The persistence of a spill is a function of the type of oil involved, amongst otherfactors. For simplicity, and to avoid establishing any other measure, the oilclassifications as described in the ITOPF Technical Information Papers can be used
as a guide to the level of response required. Generally speaking light oils such ascondensates, diesel and light crudes require minimal intervention, whilst the heavier
oils require a response. To predict this, some simple models have been developed
based on oil type. Oils have been classified into groups roughly according to theirdensity - generally, oils with a lower density will be less persistent. However someapparently light oils can behave more like heavy ones due to the presence of waxes.
Table 2 shows the relationship between the density and the oil group.
Table 2 Oil Characteristics

Oil Characteristics
GroupGroup I
Group II

Densityless than 0.8
0.8 - 0.85

ExamplesGasoline, Kerosene
Gas Oil, Abu Dhabi Crude
Arabian Light Crude, North Sea Crude Oils
Group III0.85-0.95(e.g. Forties)
Group IV
greater than 0.95
Heavy Fuel Oil, Venezuelan Crude Oils
Although simple models such as this cannot predict the changes an oil undergoes very
precisely, they can provide clues about whether an oil is likely to dissipate naturally orwhether it will reach the shoreline.

Environmental criteria
The sensitivity of the operating environment is another factor that is considered whenassessing the response criteria, areas which have a high vulnerability and sensitive
require early intervention. To measure this sensitivity, seabird vulnerabilities areassessed and these can be found in UKDMAP, 3rd Edition, July 1998, a CD-ROM
published by the Natural Environment Research Council. In essence seabird
vulnerability level 1 is given to the most at risk species.

Petroleum Association of JapanOil Spill Symposium 2001

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Aerial surveillance
One of the key tools for ensuring an effective response is the provision of aerial
surveillance. There has always been a requirement for offshore operators to provide
aerial surveillance of pollution incidents as prescribed in the Pollution Oil Notice 1(PON1). During 2000 the Department of Trade and industry rejected a number ofplans on the grounds that inadequate aerial surveillance provisions had been made,and required operators to do more.
Interim response solutions
The new guidelines meant that some UKCS operators had to review the way they
provided response. Oil Spill Response Limited had previously used the L382
Hercules and ADDs pack to meet the response requirements of North Sea operators.
The reduction in response times required the repositioning of the ADDs pack toimprove mobilisation times and a limitation being placed on the use of the Hercules
aircraft, the solution was at best an interim arrangement until a better technicalsolution could be developed. To meet the requirements of the DTI for aerial
surveillance, OSRL utilised hand held thermal imaging systems operated by skilled
observers from OSRL whilst a fully integrated response solution was established.
New services
Co-operative solutions
To provide the most cost effective solution to the problem it was clear that a cooperative approach would provide the service to the industry at a minimum cost,competition within the response industry would lead to duplication of resources andescalating costs. Oil Spill Response Limited, Briggs Marine Environmental Servicesand Atlantic Reconnaissance Limited agreed to work together to develop a technicalsolution to providing aerial surveillance and dispersant capability.
Aerial Surveillance
The aerial surveillance system that was provided for the offshore industry is provided
from a Cessna 402B aircraft, the aircraft has a speed of 160 knots and a flight
endurance of 8.3 hours. The systems carried on the aircraft permit the surveillance ofspills using infra red and visual sensors. This level of equipment is adequate for thetactical response to oil spills since operators will only mobilise the aircraft once a spillhas been reported. The information gathered by the aircraft can be relayed back to
the relevant command centre using a data link system.

Petroleum Association of JapanOil Spill Symposium 2001

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The aircraft will be based in Inverness Scotland on 90 minutes notice to fly during
daylight hours or on 120 minutes during out of hour periods.
New technology
Aerial Dispersant delivery
To meet the DTI requirement for aerial dispersant response, a small dispersant
application system was required to provide a rapid response prior to the arrival onscene of the L382 Hercules. The preferred route was to use a non-dedicated aircraft
for the role, as his would represent the most cost-effective solution, provided that theresponse time could be met. Air Atlantique agreed to develop a small dispersant
system for attachment to their Cessna 406 aircraft that are typically used to carry
cargo freight or passengers from their bases in Inverness or Coventry. The system
had to permit a rapid role change to a dispersant application mode to meet the DTI
response time of six hours.

The original prototype pod was fabricated from aluminium and incorporated anelectric dispersant pump driven from aircraft power system. Once the design had
been developed, flight-tested and approved by the authorities production subsequentmodels of the pod are to be constructed of Kevlar reinforced fibreglass. The pods
are attached to the aircraft by a series of bolts and installation is achieved in less that
one hour. The aircraft has a transit speed of 200 knots to the spill site and is able todepart to an incident within three hours of notification. Using the dispersant pods, theindustry is able to meet the response requirements of the DTI. The rate of delivery ofdispersant is significant and when combined with the capability of the L382 Hercules
is well in excess of the stated response arrangements in the guidelines and is shownin the table below.
Graph showing dispersant delivery v time
1000

Oil treated in tons

900
800
700
600
500

Dispersant
Delivery

400300starts

200
100

Time in Hours
Spill range 100 miles

Petroleum Association of JapanOil Spill Symposium 2001

Spill range 50 miles

412111098765432100

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Lockheed Electra aerial dispersant system.
As part of the re-design of the UK Government aerial dispersant response system
their was a desire to update the service to provide a larger dispersant capability using
more modern turbine aircraft. Air Atlantique were successful in the bid to provide thisservice and began the development of a spray system to be installed in a Lockheed
Electra aircraft. The system has a capacity of 13 tons, the dispersant is carried intanks on a number of conventional 88’’ x125’’pallets which can be quickly installed
into the aircraft. The dispersant is pumped using a diesel driven pump that delivers
the material to the spray arms, which are mounted at the tail of the aircraft.

Nimbus Aerial dispersant system.
One of the most recent innovations in the dispersant application field is thedevelopment of the Nimbus systems by Ayles Fernie for Oil spill response Limited.
Since 1984 the Aerial dispersant Delivery system has been a key component of theOil Industry response framework. The system has a capacity of 17 tons and isdesigned for use in conjunction with the Hercules L382 aircraft. The system has
demonstrated its value in a number of incidents, however one significant drawback is
the reliance on the Hercules aircraft to transport the system to the spill site. Theaircraft is designed as a tactical theatre transport aircraft and is not suited to longrange deployments. Having a transit speed of approximately 300 knots the aircraft
will be required to crew stop when undertaking transatlantic flights. To overcome thisthe Nimbus concept was conceived, the system being a modularised spray unit witha capacity of 12 tons, capable of deployment in a jet transport aircraft to the spill site.
The system would then be installed in a Hercules aircraft that would be deployed tothe site form the SAFAIR fleet of aircraft. The unit would be shipped along with astock of dispersant and spray capable trained crews despatched from either the UKor Singapore.

SummaryThe developments in legislation and technology reflected above represent asignificant improvement in capability to respond to an oil spill incident. The technicalsolutions in response to the changes also demonstrate cost-effective means for theindustry to meet the response requirements. The response industry has seen
dispersant application as a key strategy in the response to oil spills, the latest
technical developments add significant capability to the response tool box to achieve
this.
Petroleum Association of JapanOil Spill Symposium 2001

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