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A Forewarning For The Atlantic Frontier? Introduction In 1966 the first offshore oil platform was installed in the North Sea. Three decades on over 400 fixed steel and concrete platforms have been constructed . In the UK sector alone more than 5,000 development and production wells have been drilled and 5,000 miles of seabed pipelines laid . Over the last thirty years the resulting platforms have produced billions of tonnes of oil. However this industrial development has clearly been undertaken at the expense of the environment. Offshore operations combine several stages of activities which result in a range of adverse environmental impacts. These industrial phases include initial exploration using seismic testing, rig construction, drilling, transportation and platform decommissioning. Each step brings in its wake unwelcome by-products including severe habitat disruption, dumping of toxic wastes and atmospheric pollution. The core problem is however oil itself. Oil is a pollutant throughout its life-cycle of human use. Whether it is being spilled into the marine and terrestrial environment or burned and pumped into the atmosphere in the form of the CO2, the most ubiquitous greenhouse gas. Seismic Testing The first step in the industrialisation of the sea by the oil industry is seismic testing. This is the acoustic "trawling" of the seabed using sound waves in order to study its geophysical composition. A ship tows a source of sound (typically airguns or gas exploders) approximately 300 metres behind it. Up to eight kilometres of "streamers" are connected beyond the sound source containing hydrophones which record the reflected sound from the seabed. The sound waves give an indication of sub-surface geology and potential oil reserves. However the results are not necessarily conclusive: the oil companies have to drill to be sure that anticipated reserves exist. Although sound waves are generally directed at the seabed considerable seismic energy can be released horizontally, resulting in sound pulses being audible tens of kilometres away. The initial explosion has to be extremely loud in order for the sound waves to penetrate deep into the rock and then reflect back to the hydrophones. Scientific research has suggested that this massive resounding may disrupt whales and dolphins who live in a world of sound; relying on sonar for their navigation and communication. The noise intrusion has been compared to a blinding light in a human eye. For example in one study no cetaceans were found within 40 kilometres of the seismic testing even though it was an area where whales and dolphins were normally considered abundant . Polluting Waste During offshore exploration and drilling large quantities of polluting waste are released into the sea. This on-going backdoor dumping by the oil industry is much less reported than more visual one-off oil spills. However this constant discharge of toxic substances constitutes an insidious background pollution from offshore operations. Sources include cooling water from machinery, deck drainage and domestic sewage which may be discharged from the platforms. There is also submerged pollution from substances like anti-fouling paints and sacrificial electrodes which protect rigs from bio-fouling and corrosion. These substances contain toxic heavy metals such as chromates and arsenicals. Further pollutants and wastes are derived from initial platform construction through to the transportation of equipment, materials and products. Drill Cuttings and Muds Once reserves have been identified the next stage of oil production is drilling. Initially this is undertaken by a mobile exploration rig which confirms that supplies exist in commercial quantities. Once this is established a production rig will be positioned and wells sunk into the reserve. This drilling produces one of the main sources of pollution from offshore operations, drill cuttings and muds. Drilling muds are used to lubricate and cool the drill, to remove rock chippings from the well and to assist in well pressure. There are two main types of mud - water based (WBM) and oil based (OBM). Despite their name WBMs also contain hydrocarbons in estimated concentrations of between 100-7000 ppm . Both forms of mud contain toxic heavy metals, bentonite, inorganic salts, detergents, a variety of organic polymers, corrosion inhibitors and biocides in varying quantities. Drill cuttings are particles and crushed sedimentary rock which are produced by the drill bit when it penetrates the substrata. When drill cuttings come back up to the platform they are saturated with drilling muds. Cleaning techniques are used to try to reduce the level of drilling mud mixed with the cuttings. However, when the cuttings are subsequently dumped over the side of the installation they are still heavily contaminated with drilling muds. Total discharge of cuttings and mud fluids from development drilling in the central and northern North Sea have been estimated at 695,726 m3 . The weight of this discharge is thought to be 1,473,282 tonnes derived from 56 developments and 1,467 wells . These figures correspond to 26,309 tonnes per development and 1004 tonnes per well . Total discharge of oil with cuttings has been estimated at 67,988 tonnes from the 56 developments . These correspond with averages of 1214 tonnes per development and 46.3 tonnes per well . Between 1981 and 1986 the amount of oil discharged annually in cuttings rose from 5800 tonnes to 13000 tonnes . Of 21 developments studied the maximum vertical height of mud piles (relative to the natural mudline) varied between 2 and 20 metres . One platform alone (the North West Hutton) was found to have approximately 25,000 cubic metres of oil drilling waste beneath it . The potential impacts of drilling muds and cuttings are varied. The National Federation of Fishermen’s Organisations (NFFO) and leading scientists have stated concern that these chemicals may be harmful to fish and their larvae . Apart from the toxic impact of muds, they are also thought to smother flora and fauna on the sea bed. The oil industries’ own studies of the North Sea regarding the effects of cuttings on benthos have shown that within the cuttings pile natural benthic communities (which dwell on the sea bed) are not present and that there may be no microfauna. Up to 500 metres away from the cutting pile there is normally an impoverished area with highly modified fauna characterised by opportunist species which colonise and dominate the denuded site . Studies in Norwegian waters have indicated that "significant perturbations" in community structure have been detected many kilometres from platforms . Moreover, contamination from drilling muds can be persistent. Past research around the K12 Alpha platform showed no noticeable recovery eight years after drilling had ceased . Produced Water Once wells have been drilled and their oil is being pumped to the rig another source of contamination is "produced water". This is water which occurs naturally in the reserve and which is pumped to the platform with oil. The oil and water mix has to be separated and the ensuing waste product is called produced water. Produced water contains concentrations of metals such as barium, beryllium, cadmium, chromium, copper, iron, lead, nickel, silver and zinc . In produced water these metals can be found at higher concentrations than in fresh or salt water by a factor of 1000 . Produced water contains hydrocarbons and chemicals from the reservoir and injected chemicals from production stages. Once separated produced water is dumped at sea. Over its life-span a production field can contain 10 times more produced water than it does oil . As the industrialisation of the North Sea has expanded the quantity of oil discharged with produced water has risen dramatically. In 1979 169 tonnes of oil were released into the sea from this source. However, since 1984 the amount of oil discharged with produced water has more than doubled. 5855 tonnes of oil were discharged in 1995 alone . The precise scale of chemical usage in the North Sea remains unquantified. However, the overall chemical discharge has been estimated at 57% of drilling chemicals and 30% of production chemicals used, amounting to 84,097 and 5,934 tonnes respectively . Oil Spills Large oil spills occurring during transportation by tankers receive much media attention. In January 1993 over 50,000 tonnes of light crude oil were spilt into the sea after The Braer ran aground off the Shetland isles. In February 1996 the Sea Empress spilt 70,000 tonnes of oil off the coast of Pembrokeshire. Equally, isolated catastrophes on oil rigs tend to gain public attention. For example, the Pipa Alpha disaster in 1988 killed 167 workers when fire, fed by oil and gas pipelines from surrounding platforms, engulfed the platform. As well as the tragic loss of human life, this disaster led to 1500 tonnes of oil and 4 tonnes of transformer oils containing PCBs being spilt into the sea. Blow outs also lead to large oil spills. They occur when a well head fails to control the pressure used to pump oil up to the platform. A blow-out on the Norwegian Bravo platform in 1977 led to over 15,000 tonnes of oil being spilt. Less documented are the on-going localised oil spills. These accidental spills are derived either from the platforms, during transportation or from pipelines which can have chronic leaks or ruptures. The number of spills reported to the Department of Energy and the Department of Trade and Industry between 1979 and 1988 rose from 27 to 259 . The quantity of oil spilt also increased from 80 tonnes in 1979 to 2627 tonnes in 1988 . In 1991 35% of the spills reported were over 100 gallons . Of the 145 identified slicks in 1995 only 52 were reported by the companies themselves and only one prosecution was undertaken resulting in a fine of £1000 . Redundant Platforms Aside from the environmental impacts of oil exploration, production and transportation, at the end of an oil fields life there is the further problem of decommissioning redundant platforms. In the North Sea over 400 structures and thousands of miles worth of pipelines will either have to be removed or abandoned. This is no mean task; some of the rigs in place are larger than 30 storey buildings. Fishing communities have already expressed concern regarding abandoned platforms and pipelines on the seabed. These concerns were recently justified. On the 10th March 1997 a trawler and four crew went missing in the seas off Arbroath, Scotland. The boats last broadcast said that she had fastened on an underwater obstacle. It was later discovered that this obstacle was an oil pipe line . Furthermore there is the issue of industrial responsibility. The seas are not a dumpsite for industrial waste. In the case of decommissioning, valuable commodities such as steel, copper and aluminium can be recycled onshore, rather than being dumped at sea. Conclusion The process of offshore oil production has been found to have negative environmental impacts at every stage of its activities. This is in part due to inadequate regulation and control of industrial offshore activities. There is insufficient information on impacts of discharges and a lack of attention to the cumulative effects, disturbance impacts and to comprehensive assessments of the habitats and wildlife in or adjacent to a licensed area . Monitoring and regulation of activities is normally left in the hands of industry or the Department of Trade and Industry and even where harmful environmental impacts are anticipated, the "no activity" option is normally overlooked. However, the core problem is that the extraction of oil has environmental impacts regardless of whether it is regulated or not. Oil is a pollutant throughout its cycle of use. The industrialisation of the North Sea has been undertaken at the expense of the environment. The next industrial oil-field is destined to be the Atlantic Frontier, a near-pristine wilderness of international environmental significance. If industrialisation is allowed to develop in this area what will it be like in thirty years time? After the Rio Earth Summit John Major said "the environmental buck stops in our backyard". Yet it is our backyard which we are continuing to use as a foul marine industrial estate. References For further information please contact the Greenpeace Press Office on 0171-865 8255/6/7/8 Netherlands Government (1996) "Abandonment of North Sea Structures" Report to the OSPAR Working Group on Sea-Based Activities, Netherlands UKOOA Press Release, 25/03/97
Pullen, S. (1996) "Increasing Environmental Protection in the Oil and Gas Licensing Process", Marine Environmental Management Review of 1995 and Future Trends, Vol. 3, No 17, pp. 99-106. DTI/UKOOA (1996) Review of Drill Cuttings Piles, Altra Safety and Environment Ltd. DTI/UKOOA (1996) Review of Drill Cuttings Piles, Altra Safety and Environment Ltd. DTI/UKOOA (1996) Review of Drill Cuttings Piles, Altra Safety and Environment Ltd. DTI/UKOOA (1996) Review of Drill Cuttings Piles, Altra Safety and Environment Ltd. DTI/UKOOA (1996) Review of Drill Cuttings Piles, Altra Safety and Environment Ltd. Department of Energy (1987) "Development of Oil and Gas Resources of the United Kingdom", HMSO, UK DTI/UKOOA (1996) Review of Drill Cuttings Piles, Altra Safety and Environment Ltd. Reddy, S. (1995) No Grounds for Dumping, Greenpeace, London Reddy, S. (1995) No Grounds for Dumping, Greenpeace, London DTI/UKOOA (1996) Review of Drill Cuttings Piles, Altra Safety and Environment Ltd. Pullen, S. (1996) "Increasing Environmental Protection in the Oil and Gas Licensing Process", Marine Environmental Management Review of 1995 and Future Trends, Vol. 3, No 17, pp. 99-106. De Jong, S. A. and Zevenboom, W. (1993) Long Term Effects and Biological Recovery Upon Discharge of OBM Drill Cuttings at K-12-Alpha (Dutch Continental Shelf), 1984-1992 Report GOP 17/8/3-E; 93.4-NZ. Presented at the 17th Meeting of the Working Group on Oil Pollution of the Paris Convention for the Prevention of Marine Pollution, Ghent 9-12 February 1993 Pullen, S. (1996) "Increasing Environmental Protection in the Oil and Gas Licensing Process", Marine Environmental Management Review of 1995 and Future Trends, Vol. 3, No 17, pp. 99-106. Forstner, U. and Wittmann, G.T.W. (1983) Metal Pollution in the Aquatic Environment, Springer-Verlag, New York in Pullen, S. (1996) "Increasing Environmental Protection in the Oil and Gas Licensing Process", Marine Environmental Management Review of 1995 and Future Trends, Vol. 3, No 17, pp. 99-106. Rowell, Andy, Earth Matters, Winter 1996, Issue 32, FoE, pp. 9-11 Department of Trade and Industry (1996) "The Energy Report Vol. 2: Oil and Gas Reserves of the UK", HMSO, UK Hudgins, C. M. (1991) Chemical Usage in North Sea Oil and Gas Production and Exploration Operations. Report for the Norwegian Oil Industry Association. Petrotech Consultants Inc. Houston, Texas in Pullen, S. (1996) "Increasing Environmental Protection in the Oil and Gas Licensing Process", Marine Environmental Management Review of 1995 and Future Trends, Vol. 3, No 17, pp. 99-106. Department of Energy (1987) "Development of Oil and Gas Resources of the United Kingdom", HMSO, UK Department of Trade and Industry (1996) "The Energy Report Vol. 2: Oil and Gas Reserves of the UK", HMSO, UK Department of Energy (1987) "Development of Oil and Gas Resources of the United Kingdom", HMSO, UK Department of Trade and Industry (1996) "The Energy Report Vol. 2: Oil and Gas Reserves of the UK", HMSO, UK DoE (1993) Digest of Environmental Protection Statistics No:15, HMSO, London, 149p. in Pullen, S. (1996) "Increasing Environmental Protection in the Oil and Gas Licensing Process", Marine Environmental Management Review of 1995 and Future Trends, Vol. 3, No 17, pp. 99-106. Lawson, T (1996) Exploration or Exploitation? Natural World, No 48, Royal Society for Nature Conservation, UK Fishing News, 14th March 1997, "Two Crews Feared Lost", P1 and Fishing News, "Lives v Money" (Comment), 22 March 1997 Pullen, S. (1996) "Increasing Environmental Protection in the Oil and Gas Licensing Process", Marine Environmental Management Review of 1995 and Future Trends, Vol. 3, No 17, pp. 99-106.
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