Chapter 21. Offshore Hydrocarbon Industries
Contributors: Peter Harris (Lead member and Convenor of Writing Team) Babajide Alo, Arsonina Bera, Marita Bradshaw, Bernard Coakley,
Bjorn Einar Grosvik, Nuno Lourenco, Julian Renya Moreno, Mark Shrimpton Alan Simcock (Co-Lead member), Asha Singh
Commentators: Ana Paula Falcao, Nathan Young, Jim Kelley
1. Scale and significance of the offshore hydrocarbon industries and thei social and economic benefits.
1.1 Location of offshore exploration and production activities
Offshore oil and gas exploration and development is focused in specific geographi areas where important oil fields have been discovered. Notable offshore fields ar found in: the Gulf of Mexico (Fig. 1); the North Sea (Fig. 2); California (in the Sant Barbara basin); the Campos and Santos Basins off the coast of Brazil; Nova Scotia an Newfoundland in Atlantic Canada; West Africa, mainly west of Nigeria and Angola the Gulf of Thailand; off Sakhalin Island on the Russian Pacific coast; in th ROPME/RECOFI area‘ and on the Australia’s North-West Shelf.
1.2 Production
According to the United States of America National Research Council (2003) in  snapshot of the global offshore oil and gas industry, there were (in 2003) more tha 6,500 offshore oil and gas installations worldwide in 53 countries, 4,000 of whic were in the United States Gulf of Mexico, 950 in Asia, 700 in the Middle East and 40 in Europe. These numbers are constantly changing as the industry expands an contracts in different places in response to numerous factors involved in the globa energy market. An indicator of this volatility is that by 2014 there were only 2,41 rigs in the United States Gulf of Mexico, for example.
Global crude oil production is currently 84 million barrels per day (BPD; CI Factbook, 2012 figures) of which about 33 per cent is from the offshore (Fig. 3). Dat compiled by Infield (2014) indicate that onshore crude production plateaued a around 65 million BPD as early as the 1990s and growth in offshore production ha accounted for most of the increased global productivity since then. Production fro deep water? (>100 m water depth and as deep as 2,900 m at Shell Oil’s “Stones” field
* Regional Organization for the Protection of the Marine Environment (ROPME) Members: Bahrain Iran (Islamic Republic of), Iraq, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates Regional Commission for Fisheries (RECOFI) Members: Bahrain, Iran (Islamic Republic of), Iraq Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates.
2 Although Infield (2014) uses 500 ft (152 m) as the divide between shallow and deep water, there i no agreed definition of “deep water”. The geomorphic continental shelf break is typically around 100
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in the Gulf of Mexico) platforms accounted for about 1 per cent of production i 2000 but this figure had increased to 7 per cent by 2010 and is anticipated to reac 11 per cent of total global production by 2015 (Infield, 2014; Fig. 3).
Over 1,000 offshore oilfields are forecast to be developed between 2011 and 2015 about 80 per cent of which will be in shallow water depths (<100 m). Capita spending on shallow water platforms and pipelines is forecast to grow from a estimated 50 billion United States dollars in 2011 to nearly 60 billion United State dollars by 2015, whereas spending on deep water infrastructure is forecast to ris from 45 billion dollars in 2011 to nearly 80 billion dollars by 2015 (Infield, 2014).
Offshore natural gas production is geographically dispersed: key areas include th North Sea, Gulf of Mexico, Southeast Asia, Australia, New Zealand, Qatar, Wes Africa and South America. The geographic areas of major investment are (in order o decreasing numbers of projects): the North Sea; Southeast Asian seas; the Gulf o Mexico; Eastern Indian Ocean; and Gulf of Guinea.
In 2001, the United States received 23 per cent of its domestic natural gas from th Gulf of Mexico but by 2013 federal waters of the Gulf of Mexico provided only 5 pe cent of United States production (EIA, 2014). The reason is the fracking (hydrauli fracturing) revolution combined with horizontal drilling into tight (i.e. lo permeability) geological formations, which has led to a significant increase in th United States’ production of onshore shale gas and shale oil such that domesti production will meet US requirements in the short to medium term (until the mi 2020s). Fracking is also employed in some offshore locations (e.g. off souther California).
The southernmost offshore petroleum facilities in production in the world are in ga fields located 70 km offshore Tierra del Fuego, Argentina. These fields are currentl producing 15 million cubic metres of gas per day. The offshore platforms ar designed to resist the roughest sea conditions and wind speeds of up to 180 km/hr The northernmost facilities in production are the Prirazlomnoye oil fields, located of the coast of Russia in the Pechora Sea (adjacent to the Barents Sea). The field i estimated to hold 72 million tons of recoverable oil and production is expected t reach six million tons annually. In 2014, some 300,000 tons will be shipped out fro waters that are ice-covered for 7-8 months a year (Barents Observer, 2014).
1.3 Exploration
Oil and gas explorers rely on seismic reflection surveys to produce images of th stratigraphy and structure of subsurface rocks. They use this information t determine the location and size of oil and gas reservoirs. Globally, there were abou 142 specialized seismic vessels in operation in 2013 (Offshore Magazine, 2013) an each year the Bureau of Ocean Energy Management? gives permits for about 20 3-D
to 200 m in depth (it is around 120 m deep in the Gulf of Mexico between Texas and Florida; Harris e al., 2014), so any rig in water deeper than this is located on the continental slope (deep water) 3 On October 1, 2011, the Bureau of Ocean Energy Management, Regulation and Enforcemen (BOEMRE), formerly the Minerals Management Service (MMS), was replaced by the Bureau of Ocean
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seismic surveys in the United States Gulf of Mexico. Every seismic vessel tows  seismic source comprising a number of compressed air-guns, and an array o hydrophones in a “streamer” to capture the sound waves reflected fro sedimentary layers below. Multi-streamer marine seismic surveys can image th subsurface in 3 dimensions (3-D seismic), acquired by a vessel equipped wit between 8 and 16 streamers towed 50 to 100m apart, each 3 to 8 km long. Seismi reflection surveys are not restricted to the exploration phase but may be periodicall repeated during the production phase of an offshore field. Once in production, som oil fields are re-surveyed to assess how well the reservoir is drained over time (4- seismic).
Exploratory drilling is carried out mainly by jack-up rigs, semi-submersibles, o drillships. A jack-up rig consists of a buoyant hull fitted with extendable legs that resting on the sea floor, are capable of raising its hull over the surface of the sea There are about 540 jack-up rigs currently in operation globally, normally limited t shallow water (<100 m) drilling.
In order to explore in deep water, either drillships or semi-submersible vessels (als referred to as Mobile Offshore Drilling Units, or MODUs) are used. These vessel must maintain their position over the well to within a percent or so of water depth requiring either dynamic position capability (using powerful propeller “thrusters”) o anchoring to the seabed. The world fleet of offshore drilling ships currentl comprises about 80 vessels of various sizes and capabilities. Semi-submersibl vessels are built with ballasted pontoons with tall legs that support a platform. Onc on location the pontoons are partly flooded so that they sink below the ocea surface and wave action, while holding the platform at a safe height above th waves. When oil fields were first developed in deep water offshore locations, drillin semi-submersibles were converted for use as combined drilling and productio platforms. As the oil industry has progressed into deeper water, purpose-buil production semi-submersible platforms were designed. There are currently abou 40 semi-submersible, deep-water exploration vessels in operation globally (Offshor Magazine, 2013).
1.4 Social aspects of the offshore oil and gas industry
Over 200,000 people work on offshore rigs and platforms globally, although th exact number is difficult to estimate’. In 2011 there were 23,758 core offshor workers spending over 100 nights a year offshore on the United Kingdom’s North
Energy Management (BOEM) and the Bureau of Safety and Environmental Enforcement (BSEE) as par of a major reorganization (http://www.boemre.gov).
* The estimate of over 200,000 offshore workers was derived by adding the number for the North Se (about 24,000) to the number in the Gulf of Mexico (about 121,000) and multiplying by 1.5 to accoun for the remainder of the global workforce. It does not include shore-based staff. Another way t estimate the numbers working offshore is to use the average crew numbers (from www.oilpro.com as follows: (A) 540 jack-up exploration rigs (crew = 55 per rig) total of ~30,000; plus (B) 142 seismi vessels (crew = 80 per vessel) total of ~11,000; plus (C) 80 drill ships (crew = 80 per ship) total o ~6,500. For each crew at sea there is another crew ashore (on leave) so multiply by 2, making ove 100,000 personnel in total (oilpro.com), not including shore-based workers or the crews of fixe production platforms.
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Sea oil rigs. According to the United States Bureau of Labor Statistics, there wer 120,676 people employed in the Gulf of Mexico oil and gas industry in 2009 earnin 15.6 billion United States dollars (average income of 129,000 dollars pa). Salaries o offshore oil and gas industry workers have a broad range (Hays, 2013). In Nigeria expatriate workers are the highest paid in Africa with an average annual salary o 140,800 dollars whereas local workers in Nigeria’s oil and gas sector have an averag salary of 55,100 dollars (43 times higher than the average annual income in Nigeria which is 1,280 dollars (World Bank, 2010)). Local oil and gas sector workers hav average salaries ranging from 31,100 dollars in Sudan to 163,600 dollars in Australi (Hays, 2013). The average salaries paid to foreign workers are generally higher tha local remuneration rates, ranging from 59,800 dollars in Sudan to 171,000 dollars i Australia (Hays, 2013).
Most offshore oil workers spend extended periods, often one or more weeks, a their workplace — usually a production platform or a MODU. They then leave to liv at home onshore for a non-work period that is also commonly one or more weeks The offshore accommodations, recreational facilities and food are provided by thei employer, which also provides transportation between the workplace and som onshore “pick-up point”, commonly a heliport. This work system is variously calle “fly-in”, “fly-in/fly-out”, ”FIFO” or “long-distance commute” employment (Shrimpto and Storey, 2001).
Like other employment systems, this work pattern offers advantages an disadvantages for offshore workers, their families and the communities and region in which they live. However, it is important to note that there are importan limitations to the understanding of offshore employment effects; for example, th research to date has focused on developed countries (mostly Australia, Canada Norway, United Kingdom and of Great Britain and Northern Ireland and the Unite States), large operations and companies, fixed work schedules and married mal workers.
This work system has implications for various interrelated work and family life issues the most important of which are Health and Safety and Family Life:
Health and Safety: This includes issues relating to working in a hazardou environment, the remoteness of the operations, the hazardous and stressful natur of the commute, the use of extended shifts and rotations and in some instances th possible risk of abduction by pirates or militants.
Family Life: Offshore commute work presents challenges to famil relationships, but these must be assessed in the context of an understanding of th range of advantages and disadvantages that the system can present. As identified b workers and their family members, these are:
e income from offshore work;
e secondary and family employment e separation of work and family life e access to services and facilities;
e independence and decision-making;
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e inappropriate worker behaviour e family separation; an e isolation from and within the community.
However, these advantages and disadvantages are not always experienced in th same ways and to the same degree, with the main factors underlying such variation being differences in the availability of alternative employment, the wor environment and workers' experience of it, the regularity and security o employment, family members' experience and expectations of family life, an workers' and spouses' perceptions of the effects on the family.
Various responses and interventions may be appropriate in addressing family lif challenges, including those that improve the compatibility of the work organizatio and family life, improve the compatibility of the work culture and home life, improv self-selection during hiring, help newhires and their families get used to a new wor pattern, and provide counselling or other support to employees and famil members.
Overall, while research has shown that commute operations have somewhat highe proportions of separated and divorced workers than do conventional ones, it is no clear that this is a direct consequence of the work system, because these workplace seem to attract separated and divorced employees.
Piracy and abductions: (Kashubsky, 2011) compiled a database of 60 know attacks against maritime and petroleum infrastructure between 1975 and 2010. Ou of these incidents, 41 have occurred since 2004, the majority of which have take place in Nigeria (Kashubsky, 2011). The majority of incidents involved violenc (whether actual use of violence or threat of violence), but 15 of 60 incidents (25 pe cent) were non-violent.
Since 2006 there have been about 200 abductions in the Niger Delta of foreig workers from offshore platforms, survey vessels and pipe-laying barges. Suc abductions are carried out by militant groups, especially the Movement for th Emancipation of the Niger Delta (MEND), whose stated goals are to localize contro of Nigeria's oil and to secure reparations from the federal government for pollutio caused by the oil industry.
1.5 Communities wholly or mostly dependent upon the offshore hydrocarbo industries
Offshore petroleum activity has had significant, and sometimes dramatic, effects o infrastructure development, education and training, and research and developmen (Stantec, 2012), primarily focused on such major centres of activity as Aberdee (United Kingdom of Great Britain and Northern Ireland), Stavanger (Norway) Houston (United States), New Orleans (United States) and St John’s (Canada) Industry activity has also increased the entrepreneurship and competitiveness o local individuals and companies at the local level, and generated population growth commonly reversing previous demographic trends.
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Aberdeen is a good example of the way in which these effects can affect a port city It receives many benefits from the petroleum industry but there are als “displacement and deterrence effects” on traditional industries (Harris et al., 1988) Displacement sees existing activity being crowded out by new activity, whil deterrence sees new activity preventing other activity by making a regio unattractive for it. The offshore petroleum industry generated upward pressure o wages and increased the price of housing and office space, although industria property shortages were avoided due to an increase in warehouse and factory space The high housing prices deterred outside workers from entering the region fo employment.
As a result of these forces, several industries had local growth rates below thei national averages, while ones that were already declining saw that declin accelerate. The industries that declined faster than average in the 1970s included fishing, food and drink, clothing and footwear, building materials, and timber an furniture. Harris et al. (1988) conclude that “for every 100 jobs created by the oi industry in Aberdeen, at least eight jobs have been lost in traditional industries. B 1981, displaced and deterred employment amounted to more than 3,000 jobs. O this, only about 25 percent has been absorbed by the oil sector.”
This decline of other industries resulted in a higher dependence on the oil industry Newlands (2000) estimates that, in 1985, 40 percent of Aberdeen’s workforce relie upon oil. He also notes that, in the 1960s, “most businesses in Aberdeen were locall owned and controlled with only a few examples of external ownership [but] a surve conducted in 1984 suggested that the figure had fallen to as low as 11 percent”.
By contrast with the potential negative impacts on traditional sectors of th economy, there may also be benefits for them. Harris et al. (1988), note that “bette communications... benefit individuals as well as firms. Indeed, they are just on example of the improvement in the range and quality of services available to peopl in Aberdeen which has taken place in recent years. There has been a marke increase in the number, variety, and quality of shops and restaurants. There ar more entertainment spots such as wine bars, discos and nightclubs. Thes developments cannot be attributed wholly to the establishment of the oil industry i Aberdeen, but oil developments have undoubtedly influenced the extent and pac of change”. However, such benefits are concentrated in and around major centres o offshore petroleum activity.
Such changes have had significant positive consequences for tourism in Aberdeen Stavanger, St. John’s and other activity centres. Various studies have shown th industry making a major contribution to tourism through improved air links meetings, conferences, trade shows, corporate hospitality and the persona expenditures of petroleum industry personnel. Newlands (2000) notes that ne hotels opened, and others expanded, in Aberdeen in the 1970s. This increased th number of hotel rooms by 27 percent between 1970 and 1975 and by 58 percen between 1975 and 1980. The number of restaurants rose from 17 to 36. A simila expansion and “cosmopolitanization” of the hospitality, accommodations and henc tourism sectors has been seen in St. John’s (Shrimpton 2002).
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Generally speaking, management strategies have limited the negative biophysica environmental and other effects of offshore petroleum activity on Norway, th Shetland Islands, Nova Scotia, Newfoundland and Labrador, which continue t experience rapid growth in tourism, including eco-tourism and adventure tourism.
Harris et al. (1988) also note that: “the maintenance or improvement of service applies also to the public sector. There are better hospital facilities and a larger an more comprehensive educational system than would have been the case had oi developments not reversed the trend of economic decline and emigration fro Aberdeen”.
Given the nature of the offshore employment system (Section 1.4) it has a numbe of effects on the communities and regions where the workers live (Shrimpton an Storey, 2001), including those on:
e Residential Patterns: The commute system can give workers and thei families considerable flexibility as to where they live. Depending largely o the schedule, transportation systems and employee preferences, they ma live close to, or distant from, the workplace.
e Expenditures: Offshore work wage rates are often high, they are commonl combined with long hours of work and considerable amounts of overtime and workers generally have few expenses or spending opportunities at th workplace. As a result, these workers generally also have high disposabl incomes. Their expenditure patterns, including payment of taxes, ar largely dependent on where they live, and can make a significan contribution to the economy of those communities and regions.
e Non-Commute Employment: Some offshore employees have secondary pai work while in their home communities. This can involve the use of oi industry work skills and/or involvement in traditional local farming o fishing activity. In the latter case, offshore oil labour and incomes can hel sustain the local primary sector.
¢ Community Life and Social and Recreational Services: Offshore work remove some citizens from communities on a part-time basis, affecting their abilit to participate in formal and informal social events and networks, includin local service groups, sports teams and elected government.
1.6 Description of economic benefits to States
Daily global offshore oil production is currently about 28 million barrels (Fig. 3) which is worth between 1.4 billion dollars and 2.8 billion dollars per day (assumin 50 dollars and 100 dollars per barrel). Oil and gas production from the Unite Kingdom continental shelf (for example) has contributed 271 billion United Kingdo pounds (2008 money) in tax revenues over the last forty years. In 2008, tax rates o United Kingdom continental shelf production ranged from 50 —- 75 per cent depending on the field. The industry paid 12.9 billion pounds in corporate taxes i 2008-9, the largest since the mid-1980s, because of high oil and gas prices. Thi represented 28 per cent of total corporation tax paid in the UK. In addition to
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production taxes, the supply chain contributes another 5-6 billion pounds per year i corporation and payroll taxes (UK National Archives, 2013).
In Australia, from 1999 to 2013, the offshore petroleum industry has contribute over 21.9 billion Australian dollars in petroleum resource rent tax in addition t corporate taxes (data.gov.au, 2014).
The offshore oil and gas industry accounts for about 1.5 per cent of United State GDP, 3.5 per cent of the United Kingdom’s GDP, 12 per cent of Malaysia’s GDP, 2 per cent of Norway’s GDP and 35 per cent of Nigeria’s GDP (OPEC, 2013; EIA, 2014) In Norway, crude oil, natural gas and pipeline transport services accounted for abou 100 billion dollars in 2010, nearly half of the value of Norway’s total exports and 1 times higher than the export value of fish (Norwegian Petroleum Directorate, 2012) In Nigeria crude oil export was valued at around 94 billion dollars pa and account for about 70 per cent of total exports revenue (OPEC, 2013 figures). Thus the overal value of the offshore oil and gas industry accounts for a significant part of GDP bu varies dramatically among countries in terms of its overall importance.
Offshore petroleum activity can have a range of other impacts, some of the negative, on the local economy. Some early literature described negative effects o the local economy. For example, Galenson (1986) argues that Norway’ performance in curbing inflation was less than it might have been without oi revenues, and that they allowed the government to pursue policies that harme manufacturing: “Oil money was used to preserve the existing pattern of industry The restructuring necessary to meet changing market demands was slowed, if no stopped. New initiatives were not encouraged”. Mallakh et al. (1984) and Noren (1980) argue that one of problems was that Norwegian government polic prevented labour from moving to more productive firms and sectors. It was not onl prevented from moving to and from manufacturing, but from less to mor productive uses within manufacturing.
However, petroleum taxes and royalties can help address the challenges posed b the fact that the sector is cyclical and involves a non-renewable resource, meanin that the state’s revenue from it can be highly volatile. In 1990, Norway established  government pension fund to transfer capital from the state's petroleum revenue The fund was designed to be invested for the long term, but in a way that made i possible to draw on when required. Its purpose is to support the government's long term management of the petroleum revenues. The fund gives the government roo for manoeuvring in fiscal policy should oil prices drop or the mainland econom contract. This facilitates economic stability and predictability. The fund also serves a a tool to manage the financial challenges of an ageing population and an expecte drop in petroleum revenues.
There is growing interest, globally, nationally and locally, in creating sustainabl economic development. Notwithstanding the fact that the offshore petroleu industry activity involves large technologically-complex projects and the exploitatio of a non-renewable resource, the evidence from Canada, Norway, the Unite Kingdom, and other States indicates that it has been the engine for significant an sustainable (over many decades) economic development in a number of jurisdiction on both sides of the Atlantic. This is partly because it can make a major contribution
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to output, income, employment and government finances. Such activity has ofte also had a transformative effect, by helping to enhance the productive capacity o the economy through stimulating growth in the quantity and quality of factor input to the production process, thereby contributing to sustainable long-term economi development.
1.7 Emerging technologies and potential for future developments
An example of an emerging technology relevant to offshore oil and gas facilities i the design of structures that could be deployed on the seafloor (rather tha floating). Equipment that can be fixed directly to the sea floor, where it is relativel protected from ice and violent weather, could be used for subsea produced wate removal and re-injection or disposal, single-phase and multi-phase boosting of wel fluids, sand and solid separation, gas/liquid separation and boosting, and ga treatment and compression (Sorenson, 2013). Re-injection of produced gas, wate and waste increases pressure within the reservoir that has been depleted b production. Also, re-injection helps to decrease unwanted waste, such as flarin (because the gas that would have been flared is re-injected), by using the separate components to boost recovery.
Disadvantages of robotic (unmanned) seafloor mounted facilities include difficultie in monitoring their operation and implementing any necessary repairs. The 201 Deepwater Horizon (DWH) underwater spill in the Gulf of Mexico took months t bring under control, partly because of the challenges imposed by the water depth o the structure. The added complications that would arise in an Arctic setting, wher repairs may have to be undertaken in winter months beneath floating sea ice, ar factors that any such operations would need to address.
Another new technology is Floating Liquefied Natural Gas (FLNG) production wher the processing of gas from offshore fields takes place at sea. The world’s first FLN vessel, Shell’s Prelude, is currently under construction in the Republic of Korea fo deployment on Australia’s North-West Shelf. The LNG plant will be located on a larg vessel that will be moored above the gas field — several hundred kilometres from th coast. The successful deployment of FLNG may allow for the production of gas fro smaller or more remote offshore fields (Geoscience Australia and BREE, 2012).
A potential future development in the offshore energy sector is the possibility o mining methane gas hydrates from seabed deposits. Methane clathrate, also calle methane hydrate, is composed of methane trapped within the crystal structure o water, forming a solid similar to ice, found in seabed sediments in water depths o greater than 300 to 500 m (Ruppel, 2011). When brought to the earth's surface, on cubic metre of gas hydrate releases 164 cubic metres of natural gas. Methane tha forms hydrate can be both biogenic, created by biological activity in sediments, an thermogenic, created by geological processes deeper within the earth.  conservative estimate (Boswell & Collett 2011) for the global gas hydrate inventor is “1,800 gigatons of carbon. While global estimates vary considerably, the energ content of methane occurring in hydrate form is immense, possibly exceeding th combined energy content of all other known fossil fuels. However, methan production from hydrate has not been documented beyond small-scale field
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experiments and its contribution to global gas supply has probably been delayed b several decades by the increasing development of onshore gas resources from shale coal seams and other unconventional deposits (Geoscience Australia and BREE 2012).
2. Environmental impacts from exploration, including seismic surveys offshore facility development and decommissioning
2.1 Environmental impacts
Environmental impacts arise throughout petroleum exploration-drilling-productio development operations as well as in the decommissioning of facilities once the oi field is no longer economic, although the nature and degree of impact varies (Swa et al., 1994). Seismic surveys, oil and gas production, transportation an decommissioning all have associated environmental impacts; these are describe briefly below.
The risks of impact from oil spills are greatest during transport, from pipeline ruptur and vessel loss or spillage, when large volumes of oil can be released suddenly. It i important to realize that accidental (anthropogenic) spills occur against  background of continuous leakage from the seafloor. Crude oil is a naturally occurring substance. An amount of oil approximately equal to that spille accidentally by humans enters the oceans each year through natural seepag (Kvenvolden and Cooper, 2003; National Research Council, 2003). Natural seepage i a gradual, ongoing process and ecosystems have evolved that use it as a food source Spills are ecologically damaging because they result in unnatural concentrations o oil at a particular site that are incompatible with local marine life.
Also it should be noted that accidental oil spills account for only a small percentag of the total volume of oil that enters the oceans due to humans. Most oil enters th ocean mixed with sewage and urban stormwater runoff (GESAMP, 2007) but suc diffuse sources do not have the same dramatic impact on ecosystems as a spil because the oil is delivered continuously in low concentrations over a broad area The long-term effects of low-level oil pollution from diffuse sources are unknow (GESAMP, 2007).
2.2 Drilling and production activities
Drilling activities are carried out from ships or fixed platforms during exploration an to extract oil once it has been found. Direct damage to the seafloor is caused by th anchors used to hold the rig in place as well as by the impact of the wel emplacement itself. Drilling requires the use of lubricant (drilling mud) and th disposal of drill cuttings onto the seabed at the drill site. Drilling mud and some o the drill-cuttings contain crude oil residues, polycyclic aromatic hydrocarbons (PAHs and heavy metals that can be toxic. The environmental impacts of drilling ma include smothering the seabed by blanketing it with dense drilling mud and cutting and toxicity effects (Swan et al., 1994). The initial impact is generally confined to the
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immediate surrounds, typically within 150 m of the drill site. However, Olsgard an Gray (1995) reported that barium, total hydrocarbons, zinc, copper, cadmium an lead contamination sourced from production platforms on the Norwegian shelf ha spread considerably after a period of 6 to 9 years, so that evidence of contaminatio was found 2 to 6 km away from the platforms. This led to a ban in the North Sea o discharging oil-based muds or cuttings contaminated with them from 1993. The ba gradually decreased the affected zone around drilling installations from several k to approximately 500 m (Bakke et al., 2013).
During the production of oil and gas, water from the hydrocarbon reservoir is als brought to the surface. This is known as “produced water” (PW), is a by-product o oil production and it is either disposed of into the ocean or may be re-injected int the well to promote oil recovery (Swan et al., 1994). Produced water can als include sea-water injected into the well to promote recovery. Compared wit ambient seawater, PW may contain elevated concentrations of heavy metals (e.g arsenic, mercury, barium, copper, lead and zinc), radium isotopes, as well a hydrocarbons. The proportion of oil/water varies between locations but generall the proportion of water increases over time as the oil deposit is depleted (i.e. olde wells discharge more PW than new wells). The proportion of water produced pe barrel of oil typically ranges from around 3:1 to 7:1 although the relative amount o PW increases over time, such that in extreme cases the fluid pumped from a wel might be 98 per cent water and only 2 per cent oil (Holdway and Heggie, 2000). A the production platform, most of the PW is separated from the oil, treated (typicall to around 30 mg/L hydrocarbon) and disposed of into the ocean. Because th increase in the absolute amount of PW discharged leads to an increase in th absolute amount of oil discharged, unless the proportion of oil in the PW discharge is decreased, regulatory measures have been adopted in some areas, such as th North Sea, which have resulted in reductions between 2001 and 2006 of around 3 per cent in the amount of oil discharged in PW (OSPAR Decision 2001/1; OSPA 2010).
PW forms a buoyant plume because it is typically 40° to 80°C warmer (and therefor less dense) than ambient seawater and thus it will be dispersed by wind and current away from the production platform. Mixing and dilution with seawater results i toxic effects of PW being generally confined to within 1 km of production platforms although PW plumes may be detected in surface waters for distances exceeding 1 km from the point source (Jones and Hayward, 2003). Cases of coral discolouratio (coral bleaching) have been attributed to dilute (~12 per cent) PW concentration (ITOPF, 2007). Hence, the situation of production platforms in relation to prevailin winds and currents and to the proximity of sensitive habitats is a consideration fo offshore petroleum development.
There are additional environmental consequences of the emplacement of rigs an floating platforms into the marine environment, which include effects on migrator birds and artificial habitat. Electric lights used on the rigs have been shown t interfere with the natural migration pathways of some species of birds, causing the to accidently collide with platform structures. Although the actual numbers of bird killed due to having collided with platforms is unknown, modelling has shown tha the numbers could be significant (OSPAR, 2012b). Any seafloor disturbing activities
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such as anchor placement and retrieval, drilling, construction and decommissionin activities, and jetting into the seafloor for pipeline trenches has the potential t disturb or cause permanent and irreversible damage to natural and cultura resources. Underwater cultural heritage such as shipwrecks and submerge prehistoric sites are especially vulnerable to seafloor disturbing activities as thes resources are finite and each site is unique. Natural resources such as coral reefs fish habitat, and deepwater chemosynthetic communities can also be impacted b these activities. In order to reduce the risk of damage in United States waters, th United States Bureau of Ocean Energy Management (BOEM) requires the operato to conduct high-resolution geophysical surveys to identify potential resources befor the operator can receive their permit and commence seafloor disturbing activities.
Once in place, the legs (jacket) of an offshore platform become habitat for som species of fish and sessile marine biota and can create a local area of elevate biomass and biodiversity. This is because access to the immediate area around th platform is restricted for reasons of safety such that the platform creates a zone tha acts as a de facto marine reserve. In addition, the steel structure provides a har substrate for colonization that would otherwise not be present, thus artificiall increasing the local biodiversity (Page et al., 1999; Shaw et al., 2001; Whomersle and Picken, 2003).
Over the lifespan of a platform, shell debris derived from molluscs that colonize th platform legs accumulates at the base of the platform. The shell accumulation i draped over drill cuttings (described above) forming a characteristic, mound-shape deposit. The shell drape provides a new habitat that has different properties fro the surrounding seabed and thus offers habitat to different species. Disturbance o the shell drape will expose the (potentially toxic) drill cuttings that are a factor fo consideration for rig decommissioning.
Because of the biological colonization of MODUs, the relocation of the vesse between drilling locations has been identified as a vector for the introduction of non native species (Paula and Creed, 2005; Sammarco et al., 2010).
2.3 Seismic surveys and their impact on marine mammals and other ocean life
Marine acoustic survey equipment is used by the oil and gas industry as well as b the military, marine industries and academic researchers to map the seafloor, stud the sediments beneath the seafloor and image the water column. Depending on th purpose, sonars differ in frequency, source level and beam pattern. Sonar signal diminish as they propagate, affecting different parts of the water column wit different biological consequences. Towed, low frequency systems (such as seismi air guns) are omni-directional, radiating sound in all directions. Hull-mounte systems are higher frequency (kHz or greater) and utilize beam forming to obtai higher resolution images at lower source levels.
Airguns employed to acquire seismic reflection data are far more powerful (225 t 255 decibels re 1 micro-Pascal peak; Richardson et al., 1995) than equipment use for marine research or normal ship navigation. Airguns used in seismic reflectio surveys emit sound at a frequency of typically ~100 Hz which overlaps with the range
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of marine mammals’ hearing and is therefore most likely to affect marine mammal and other marine life (McCauley et al., 2000; O’Brien et al., 2002; NRC, 2003; Boebe et al., 2005; Nowacek et al., 2007; 2013; CBD, 2014).
Cetaceans have been observed avoiding powerful, low frequency sound sources.  study by McCauley et al (2000) has shown that migrating humpback whales wil leave a minimum 3 km gap between themselves and an operating seismic vessel with resting humpback whale pods (groups) containing cows exhibiting increase sensitivity and leaving an increased gap of 7-12 km. Conversely, the study found tha male humpback whales were attracted to a single operating airgun as they wer believed to have confused the low-frequency sound with that of whale breachin behaviour. In addition to whales, sea turtles, fish and squid all showed alarm an avoidance behaviour in the presence of an approaching seismic source. While ther has not been any documented direct linkage between seismic surveys and th beaching of marine mammals, Gordon et al., (2004) noted that concerns over th stranding of beaked whales in two separate incidents was sufficient for United State courts to agree to a restraining order on seismic operations by the RV Mauric Ewing. Nowacek et al. (2007) noted that displacement (relocation to an un impacted area) is a common response of mammals, which may cause harm if th impacted site is an important feeding ground (see also Cerchio et al., 2014). Lucke e al (2009) found that harbour porpoises consistently showed aversive behavioura reactions at received sound pressure levels above a certain threshold level produce using a seismic airgun.
The historical record of cetaceans stranding themselves prior to the industrial ag includes the English Crown holding rights on stranded cetaceans from at least 1324 when they were known as “fishes royal” since the Crown had first claim on the (Fraser, 1977). Thus cetacean stranding occurs under natural environmenta conditions. Additional evidence in support of this conclusion is the occurrence o marine mammal strandings within the geological record (Pyenson et al., 2014).
It is not known whether there has been any increase in whale strandings that can b attributed directly to seismic surveys. Nowacek et al. (2007; 2013) conclude tha major data deficiencies are: the lack of studies linking animal responses to receive acoustic level data; gaps in species representation; and poor understanding o habituation, sensitization and tolerance. In the case of marine animals other tha cetaceans, there is some evidence for short-term displacement of seals and fish b seismic surveys, but there is little literature available (Thompson et al., 2013; se also Chapter 37).
2.4 Pipeline construction, main causes of leaks and decommissioning
In order to bring oil and gas ashore to refineries and transport systems, pipelines ar laid across the seabed, in places forming complex networks (Fig. 2).° Before  pipeline can be laid, the proposed route is surveyed using acoustic seabed mappin technology and underwater cameras to identify any obstacles such as natura bedrock formations, boulders, seabed valleys or migrating sand dunes as well as
° The following summary of pipeline construction is based primarily on Palmer and King (2004).
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shipwrecks, other cables and pipelines and dumped ammunition. The pipe is the laid along the surveyed route using either a specialised pipe-laying vessel or else  pull/tow system where the pipeline is built onshore and then towed by ship to it desired location. The first process usually involves one pipe-laying vessel supporte by barges that supply the ship with pipe sections plus other support ships tha monitor the seabed. Pipe sections are welded together on board, the joints teste (by ultrasound) and the pipe coated with an anticorrosion application.
The diameter of the pipe varies between 0.15 to 1.4 m, but is ~0.3 m in most cases A distinction is made between a flowline and a pipeline. Flowlines are intrafiel pipelines used to connect subsea wellheads, manifolds and the platform within  particular development field. Pipelines (export pipelines, also called trunk lines) ar used to bring the resource to shore.
Problems that affect the stability and integrity of submarine pipelines are: (1 expansion/contraction of the steel pipe causing lateral or upheaval buckling; (2 erosion of the seabed around the pipeline by storms, waves and currents leavin unsupported spans of pipeline vulnerable to fracture; and (3) corrosion. Solutions t the expansion/contraction problem are: adding expansion joints; burial; anchoring applying a concrete or rock cover; or laying the pipe in an “S”- shaped configuratio (S-lay). Problems of seabed erosion can be overcome by burial (Xu et al., 2009; Yan et al., 2012). Burial of the pipeline is also required in areas where vessels migh anchor, where bottom fishing activities occur or where the pipeline crosses th shoreline. However, burial is more expensive than simply laying the pipeline alon the seabed, so it is not used unless necessary (or a legal requirement).
Pipelines are maintained and inspected using a “pig,” a tool that can be inserted i one end of the pipeline and pushed by the fluid to the other end. The most basic pig are used to clean the inside of the pipes; highly-complex “smart pigs” can inspect th condition and thickness of the pipeline and detect points of corrosion or fracturing Smart pigs are used more in the North Sea than in the Gulf of Mexico because th majority of existing Gulf of Mexico lines were not originally designed or built t accommodate smart tool pigs (MSL, 2000).
Pipelines are monitored for leakage by analog and computer-assisted system (Stafford and Williams, 1996). The mass balance approach simply measures th amount of oil going in the pipeline and the amount coming out. Real-time transien modelling compares actual measured data with a computer model. If the results ar outside normal operating limits, an alarm alerts the operator to take appropriat action. Other methods of monitoring pipelines include chemical and radioactiv tracers, acoustic emission, neural networks, fibre-optic sensors and pressure poin analysis (Stafford and Williams, 1996).
Woodson (1990) compiled a database of 1,047 submarine pipeline failures reporte in the Gulf of Mexico between 1967 and 1990. The results indicate that a pipelin failure occurred in the Gulf of Mexico on average once every 5 days over the perio of data collection. The source of failure was reported in 916 incidents in which th main causes were attributed as follows: 50 per cent (456 out of 916 incidents) due t internal or external pipeline corrosion; 12 per cent (106 incidents) due to storms an hurricanes; 14 per cent (124 incidents) due to damage from ship’s anchors and
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fishing gear; 10 per cent (94 incidents) due to material failure of valves, gaskets o other joints; and 15 per cent (136 incidents) due to other or unknown causes Pipelines over 10 years in age had a greater number of failures due to corrosion tha younger pipelines; there was a trend of an increasing rate of failure due to corrosio in the last 5 years of the database (1986-1990), presumably attributable to the agin of the pipeline network. Pipelines damaged by storms (in which pipes are excavate by waves and currents exposing an unsupported span that is liable to fracture) wer not buried in 40 out of 52 cases (Woodson, 1990).
In its review of offshore pipeline safety, the United States Marine Board Committe on the Safety of Marine Pipelines (Marine Board, 1994) cited the work of Woodso (1990) and noted that during the 1990s, transmission and production pipelin leakage and accidents accounted for about 98 per cent of accidental releases b offshore production activities. However, although corrosion is the most commonl cited cause of pipeline failure, corrosion-related ruptures do not result in significan release of oil into the environment. Rather, damage caused by a few major incident involving ship’s anchors caused pipe leakage that is attributed to 95 per cent of th 250,000 barrels that leaked from pipelines in the Gulf of Mexico from 1967 to 199 (Marine Board, 1994).
The National Research Council (NRC) (1997) noted that, in the United States Gulf o Mexico “no agency coordinates the collection of information and the available dat on offshore pipeline failures are correspondingly “incomplete”. Data on pipelin failures from state waters are collected by states (when collected) and may not b readily accessible. This is in spite of the fact that pipelines in state waters ar commonly the oldest and most exposed to collision with ships (Marine Board, 1994) Since 2006, data on offshore pipelines (outside of state waters) has been th responsibility of the Bureau of Safety and Environmental Enforcement (BSEE).
In Europe, a pipeline data base complied by PARLOC (2001) includes records fro 1971 to 2000 during which time there were 542 pipeline incidents including 9 pipeline leaks into the environment plus 92 leaks of pipeline fittings. The cause o failure of pipeline fittings is not recorded (PARLOC, 2001); for pipelines the databas shows that corrosion is the major cause of failure (51 per cent) followed by maritim actions such as anchoring (23 per cent), material failure and other or unknow causes (26 per cent).
Less than 2 per cent of the North Sea pipeline inventory has been decommissione as of 2013 (Oil and Gas UK, 2013). Of North Sea pipelines that have bee decommissioned, 80 per cent are less than 16 inches (40.64 cm) in diameter. Half o the larger diameter pipelines (16 inches (40.64 cm) or greater) decommissioned t date were removed (i.e. 10 per cent of decommissioned pipelines were removed) Cleaning and purging is carried out following cessation of production, pipelin system depressurisation and removal of bulk hydrocarbons. Cleaning involve chemical cleaning to detach hydrocarbon residue from the pipe wall and bi directional magnetic, disc and brush cleaning to remove ferrous and other loos debris using a specialist pig (Oil and Gas UK, 2013; see also Chapter 20).
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The Gulf of Mexico offshore oil and gas has been operating since 1936 (Owen, 1975 and more of the pipeline infrastructure has been retired than in other parts of th world. Rach (2013) reported, based on data from the United States Bureau of Safet and Environmental Enforcement, that the inventory of Gulf of Mexico pipelines (a of mid-2013) includes 24,126 miles (38,827 km) that are in active use, 2,409 mile (3,877 km) proposed for installation, 12,628 miles (20,323 km) that have bee abandoned, 2,264 miles (3,643 km) proposed to be abandoned and 2,425 mile (3,902 km) of pipeline that are out of service. Thus 42 per cent of existing (66,69 km) pipelines in the Gulf of Mexico are either abandoned, proposed to b abandoned or are no longer in service.
Apart from leakage of oil, other environmental and economic consequences o abandoned pipelines are their impacts on fishing (inhibiting bottom-trawling), othe pipe and cable-laying activities and creating artificial habitats.
2.5 Rig decommissioning, dismantling and disposal, “Rigs to Reefs” programme
In its assessment of environmental governance in 27 developing countries, th World Bank (2010) found that governments lack a policy and process fo decommissioning and abandonment and do not routinely assess, determine, o assign the future liability costs of decommissioning and abandonment. Only abou 50 per cent of countries have an established process for managing th decommissioning and abandonment of oil and gas projects. Disposal of man-mad structures (including platforms) at sea and abandonment or toppling on site of man made structures falls under the scope of the Convention on the Prevention o Marine Pollution by Dumping of Wastes and Other Matter, 1972 (1972 Londo Dumping Convention) (LDC) and the1996 London Protocol (LP). These treaties ar global agreements and provide relevant dumping management policies, provisions and assessment guidelines (London Convention and Protocol/UNEP, 2009). Th 1989 International Maritime Organization (IMO) guidelines provide for the remova of offshore installations in order to leave 55 metres of clear water over any remain left in place (IMO, 1989).
In the United States, the BSEE has jurisdiction over decommissioning of wells an structures, pipelines, and the so-called “Rigs-to-Reefs” program. The Rigs-to-Reef programme is the practice of converting decommissioned offshore oil and gas rig into artificial reefs, which has occurred mostly in the Gulf of Mexico. However, les than 10 per cent of rigs decommissioned in the Gulf of Mexico have so far bee converted to reefs; 90 per cent are removed (The Economist, 2014; BSEE data) Apart from a few platforms converted to reefs in Brunei Darussalam and Malaysia opposition to the practice has meant that none have been allowed off California o in the North Sea to date (Day, 2008; Macreadie et al., 2011, 2012; Jorgensen, 2012) In the North Sea, 122 decommissioned installations were brought ashore betwee 1999 and 2010, and four large concrete installations and the footings of one larg steel installation have been left in place (OSPAR 2010). One estimated cost o removing the existing North Sea production platforms, in the United Kingdom secto alone, was over 14 billion dollars (Prince, 2004). About 60 rigs are nearing the end o their working life in Australia (Macreadie et al., 2011).
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The BSEE has granted permits for about 420 platforms to be converted to artificia reefs in the Gulf of Mexico. There are three methods for converting a non-producin platform into an artificial reef: (1) partially remove the platform; (2) topple th platform in place; or (3) tow-and-place the platform to one of about 28 site designated as an artificial reef area. Partial removal typically relies on non-explosiv means to cut the platform below the sea surface, leaving the legs in their vertica position. Toppling in place uses non-explosive or explosive severance to cut th platform from its legs and lay the platform legs on their side (the platform itself i removed). The tow-and-place method entails removing the platform and detachin the structure from the seafloor before towing it to a designated artificial reef are for disposal.
In the United States Gulf of Mexico there were about 2,996 production platforms a of March 2013, of which 813 (27 per cent) are no longer producing. In 2010, th United States Government issued notices to companies requiring them to se permanent plugs in nearly 3,500 nonproducing wells and dismantle about 65 unused oil and gas production platforms (Rach, 2013). | Decommissioning mean ending operations and returning the lease or pipeline right-of-way to a conditio that meets the requirements of regulations of BSEE and other agencies that hav jurisdiction over decommissioning activities. The regulations apply to an installation, other than a pipeline, that is permanently or temporarily attached to th seabed. Very few deep sea (>200 m depth) oil and gas fields have as yet bee depleted, hence decommissioning of infrastructure has not yet become an issu (Macreadie et al., 2011).
Regulations for the decommissioning of a platform vary between countries. Th United States requires plugging the well(s) supported by the platform and severin the well casings 15 feet (5 m) below the seabed; cleaning and removing al production and pipeline risers supported by the platform; removing the platfor from its foundation by severing all bottom-founded components at least 15 feet ( m) below the seabed; disposing of the platform onshore or placing the platform a an artificial reef site; and cleaning the platform site to ensure that no debris o potential obstructions remain. Over the lifespan of a platform a mound of debri accumulates beneath the platform that may contain toxic chemicals; removal of suc mounds is also a requirement for decommissioning.
In the North Sea, OSPAR Decision 98/3 requires the topsides of all decommissione installations to be removed to shore and all sub-structures or jackets weighing les than 10,000 tons to be completely removed. The regulations stipulate that, wher there may be practical difficulty in removing installations (i.e. the footings of larg steel platforms weighing over 10,000 tons, the concrete gravity based platform sub structures, or concrete anchor bases and other structures with significant damage o deterioration, which would prevent removal), a decision may be taken to leave part of the structure on the seabed, on a case-by-case basis.
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3. Offshore installation disasters and their impacts, including longer-ter effects.
3.1 Impacts of offshore installation disasters
Impacts of offshore oil and gas installation disasters include loss of human life, los of revenue and environmental impacts. Offshore disasters have resulted in loss o life on several occasions in the history of the offshore oil and gas industry. In Marc 1980, the “flotel” (floating hotel) platform Alexander L. Kielland capsized in a stor in the North Sea with the loss of 123 lives. In February 1982, the Ocean Range semi-submersible mobile offshore drilling unit sank on the Grand Banks o Newfoundland; none of the 84 crew members survived. In July 1988, 167 peopl died when Occidental Petroleum's Piper Alpha offshore production platfor exploded in the United Kingdom sector of the North Sea after a gas leak. In 200 Petrobras-36 in Brazil exploded and sank five days later killing 11 people. In Apri 2010, the Deepwater Horizon platform exploded, killing 11 people. The Kolskay floating oil rig capsized and sank in the Sea of Okhotsk in December 2011, killing 5 crew members. In December, 2013, a rig owned by Saudi Arabia's state-ru petroleum company, Aramco, sank in the ROPME/RECOFI area, killing three cre members. Such disasters have resulted in the imposition of new regulations o industry (Turner, 2013); for example, the Piper Alpha disaster resulted in the Unite Kingdom Government passing the 1992 Offshore Installations (Safety Case Regulations. However, there have been subsequent disasters around the world an the industry, as a whole, has continued to make the changes needed to improve it safety record (Harris, 2013).
From 2001 to 2010, the United States Minerals Management Service reported 6 offshore deaths, 1,349 injuries, and 858 fires and explosions on offshore rigs in th Gulf of Mexico. During 2003-2010, the United States oil and gas extraction industr (onshore and offshore, combined) had a collective fatality rate seven times highe than that for all United States workers (27.1 versus 3.8 deaths per 100,000 workers Centers for Disease Control and Prevention, 2013). Catastrophic events attrac intense media attention but do not account for the majority of work-relate fatalities during offshore operations. A report by Baker et al. (2011) found tha helicopter crashes were the most frequent fatal event in this industry.
Economic impacts stemming from offshore oil and gas installation disasters includ the direct loss of income for the period that the facility remains offline, the costs t repair the facility, the costs to other industries (e.g. fishing and tourism) affected b the disaster and other compensation. As a result of the Deepwater Horizon oil spill BP established a Trust Fund of 20 billion dollars for natural resource damages, stat and local response costs and individual compensation. Other industry-wid consequences may follow such disasters. For example, exploration drilling in th Gulf of Mexico was slow to recover from the moratorium that followed th Deepwater Horizon oil spill in 2010. By 2012 36 rigs were back working off Louisian and 4 off Texas, compared with 21 and 2, respectively, in late 2010. On 3 June, 2008 a high-pressure 12 inch export sales gas pipeline (SGL), critically weakened by  region of external corrosion, ruptured and exploded on the beach of Varanus Island
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off the coast of Western Australia. There was approximately 60 million Australia dollars in damage to the plant. Plant closure led to up to 3 billion dollars of losses t the West Australian economy, which lost 30 per cent of its gas supply for tw months.
A blowout of the Montara wellhead platform on 21 August 2009, on Australia’ remote North-West Shelf, leaked an estimated 30,000 barrels of crude plus a unknown quantity of gas until 3 November 2009 (total of 74 days), when the lea was finally stopped. The rig later caught fire but all 69 workers on the rig were safel evacuated with no injuries or fatalities. The company spent about 5.3 millio Australian dollars on clean-up, about 300 million dollars in lost revenue and repai bills and was fined 510,000 dollars in August 2012 by the Australian Governmen (ABC News, 2012); the well finally went into production in June, 2013. However fishermen and seaweed farmers in Indonesia are seeking compensation with suppor from the Australian Lawyers Alliance (ALA), claiming that environmental damag caused by the spill has cost them more than 1.5 billion dollars per year in los earnings (ALA, 2014).
In 1980, within the ROPME/RECOFI area, the Hasbah Platform Well 6 blew out for  days, spilling 100,000 barrels of oil and costing the lives of 19 men. However, th worst disaster in the region occurred during the 1991 war between Iraq and Kuwait when there were 22 incidents that spilled amounts of oil variously estimated a between 2 and 11 million barrels into the ROPME/RECOFI area (Khordagui and Al Ajmi, 1993; Elshorbagy, 2005). The coast of Saudi Arabia was the most heavil impacted by the spill. Initial assessments of the environmental damage caused b the spilled oil were optimistic of rapid recovery (e.g. Fowler et al., 1993), but mor recent studies have documented lingering effects of oil trapped in intertida sediments and salt marshes over broad spatial scales (Michel et al., 2005; Barth 2007). As of 2011, the Government of Saudi Arabia had invested 180 million Unite States dollars and the United Nations had spent U45 million dollars in rehabilitatin impacted areas.
Natural disasters also take a toll on offshore oil and gas facilities. In August 2005 Hurricane Katrina affected 19 per cent of United States oil production by destroyin 113 offshore oil and gas platforms, damaging 457 oil and gas pipelines, and spillin an unquantified amount of oil (http://www.bsee.gov/Hurricanes/2005/katrina/).
Environmental consequences of offshore oil and gas installation disasters ar perhaps the most widely publicized aspect of such events. In the 2010 Deepwate Horizon (DWH) Gulf of Mexico oil spill, it is estimated that around 4.9 million barrel (about 670,000 tons, assuming a specific gravity of 0.88) was discharged into the se before the well was capped, approximately 16 times more oil than was spilled by th Exxon Valdez in 1989 (about 37,000 tons of crude oil; Crone and Tolstoy, 2010; Oi Spill Commission, 2011). The impact of this huge volume of oil on deep wate habitats in the Gulf of Mexico is unknown at the time of this writing (April, 2014) Prior to the DWH incident, the total volume of oil spilled in the Gulf of Mexic between 1964 and 2009 is estimated to be 517,847 barrels (Mufson, 2010).
Numerous smaller-sized spills have also occurred in recent years. Examples include  North Sea spill of 200 tons in August 2011 that occurred at Shell’s platform Gannet
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Alpha; in 2012 Chevron suspended activities after two oil leaks (of around 5,00 barrels) occurred in a space of four months off the Brazilian coast; in March 2012 th platform Elgin-Franklin, operated by the Total group in the North Sea, was evacuate after an uncontrollable gas leak of an estimated 300 million cubic feet over a 45 da period (Beall and Ferreti, 2012).
The number of accidents reflects the massive scale of the offshore drilling an production enterprise. For every accident there are environmental consequences Before the Deepwater Horizon accident, such major incidents were anticipated t occur with such extreme rarity that they were not considered relevant. On explanation could be that risk assessments are performed for single wells and not fo whole areas (or on an industry-wide basis). However, a study of accidental oil spill based on global historical data has shown that the DWH accident was not an outlier but an accident that can happen every 17 years with an uncertainty interval from  to 91 years (5-95 per cent). When the DWH accident was excluded from the dat set, the resulting frequency was 23 years with an uncertainty interval from 10 to 17 years (Eckle et al., 2012).
Accidents that occur in coastal waters have the most severe environmental impact Most oil floats on the sea surface where it can be readily delivered to the shoreline where the concentrated consequences are evident. The coast is also a habitat for  diversity of species of birds, mammals, invertebrates and marine plants. For thi reason spills that impact the coast, such as the Exxon Valdez spill that occurred i Alaska in 1989, have the greatest impact on the ecosystem (Shaw, 1992). The spee of ecosystem recovery is generally slower for colder and deeper habitats than it i for warmer and shallower habitats (Harris, 2014). However, every ecosystem i different and recovery times are difficult to estimate. For example, oil spilled in th Niger Delta over the last 50 years has penetrated up to 5 m into the soil profile an caused groundwater contamination in 8 out of 15 sites investigated that could tak up to 30 years to clean up (UNEP, 2011).
3.2 Impact of oil spills on the marine ecosystem
The impacts of oil spills range from the immediate effects of oiling to longer ter consequences of habitats being modified by the presence of oil and tar balls. Trace of hydrocarbons can remain in coastal sediments for many years after an oil spil (Hester and Mendelssohn, 2000). For example, for some of the rocky shores wher oil stranded after the Exxon Valdez spill in 1989, oil is still found subsurface, onl slightly weathered (Irvine et al., 2014). Similarly, oil from the 1991 Gulf War is stil apparent in intertidal sediments and in salt marshes along the coast of Saudi Arabi (Michel et al., 2005; Barth, 2007).
There is no clear relationship between the amount of oil spilled in the marin environment and the likely impact on wildlife. A smaller spill at a particular season o the year and in a sensitive environment may prove much more harmful than a large spill at another time of the year in another or even the same environment. Eve small spills can have very large effects. Species that use the sea surface are mos vulnerable (birds and mammals) and the eggs and larvae of many other species ca be damaged by oil (Alford et al., 2014).
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Some species may exhibit reduced abundance due to spills (SAnchez et al., 2006 although direct causal evidence is not always available (Carls et al., 2002). Som opportunistic species are able to take advantage of the changed habitat condition and the attendant reduced abundance of impacted species, giving rise to a short term increase in local biodiversity (Edgar et al., 2003; Yamamoto et al., 2003); this i an example of why biodiversity statistics alone are not a reliable indicator o environmental health. Recovery time for sites varies as a function of the type of oi spilled, the biological assemblage impacted, substrate type, climate, wave/curren regime and coastal geomorphology and ranges from years to decades depending o these and other factors (Ritchie, 1993; Jewett et al., 1999; French-McCay, 2004).
There are a number of pathways for oil to reach the oceans, namely e Land-based sources (urban runoff, coastal refineries) ¢ Oil transporting and shipping (operational discharges, tanker accidents) ¢ Offshore oil and gas facilities (operational discharges, accidents, blow-outs) e¢ Atmospheric fallout e Natural seeps.
Figures published by National Research Council (2003) range from an average o 470,000 tons to a possible 8.4 million tons per year for the sum of all of thes sources. It is generally agreed that the largest single source is the land-based (urba runoff, coastal refineries) input, although there is little agreement on the absolut values for any source terms.
When oil enters the sea, it reacts according to physical, chemical and biologica processes that change the properties of the oil and consequently, its behaviour Factors include:
- The quantity and duration of the discharge/spill;
- The time of the year at which it occurs;
- The temperature of the air and the receiving water body;
- The weather and sea (e.g. waves and currents) conditions;
- The species composition in the area affected;
- The properties of the shoreline (rocky, sandy, mud flats, mangroves, etc.) - The presence and abundance of oil-degrading micro-organisms;
- The concentration of dissolved oxygen in the water.
Different types of oil have different physical properties, which affect the wa the oil will react in the environment (Table 2).
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Table 2. Oil classification for four groups having different physical properties according to th International Tanker Owners Pollution Federation Limited (ITOPF; http://www.itopf.com/marine-
spills/fate/models/) Group Density Example Group | < 0.8 Gasoline, Kerosen Group II 0.8 - 0.85 Gas Oil, Abu Dhabi Crud Group III 0.85 - 0.95 Arabian Light Crude, North Sea Crude Oil Group IV >0.95 Heavy Fuel, Venezuelan Crude Oils
Oil, when spilled at sea, will normally break up and be dissipated or scattered int the marine environment over time. This dissipation is a result of a number o chemical and physical processes that change the compounds that make up oil whe it is spilled. The key natural processes are evaporation, dispersion, dissolution oxidation, emulsification, biodegradation and sedimentation. The addition o chemical dispersants (also surfactants) can accelerate this process of natura dispersion.
Lighter components of the oil will evaporate to the atmosphere. The amount o evaporation and the speed at which it occurs depend upon the volatility of the oil Evaporation of oil with a large percentage of light and volatile compounds occur more quickly than one with a larger amount of heavier compounds.
Waves, currents and turbulence at the sea surface can cause all or part of a slick t break-up into fragments and droplets of varying sizes. These become mixed into th upper levels of the water column.
Water soluble compounds in oil may dissolve into the surrounding water. Thi depends on the composition and state of the oil, and occurs most quickly when th oil is finely dispersed in the water column. Components that are most soluble in se water are the light aromatic hydrocarbons compounds, such as benzene an toluene. However, these compounds are also those first to be los through evaporation, a process which is 10-100 times faster than dissolution.
Oils react chemically with oxygen either breaking down into soluble products o forming persistent compounds called tars. This process is promoted by sunligh although it is very slow even in strong sunlight such that thin films of oil break dow at no more than 0.1 per cent per day. The formation of tarsis caused by th oxidation of thick layers of high viscosity oils or emulsions. This process forms a outer protective coating of heavy compounds that results in the increase persistence of the oil as a whole. Tar balls, which are often found on shorelines an have a solid outer crust surrounding a softer, less weathered interior, are a typica example of this process.
Emulsification occurs when two liquids combine, one suspended in the other Emulsification of crude oils refers to the process whereby sea water droplet become suspended in the oil. Oils with an asphaltene content greater than 0.5 pe cent tend to form stable emulsions which may persist for many months after the
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initial spill has occurred. Emulsions may separate into oil and water again if heate by sunlight under calm conditions or when stranded on shorelines.
Sea water contains a range of micro-organisms or microbes that can partially o completely degrade oil to water soluble compounds and eventually to carbo dioxide and water. Many types of microbe exist and each tends to degrade  particular group of compounds in crude oil (Hazen et al., 2010).
Sinking usually occurs due to the adhesion of particles of sediment or organic matte to the oil, in which case the oil accumulates in the seabed sediments. In th ROPME/RECOFI area for example, Elshorbagy (2005) reported that oil-contaminate seabed sediments occur, particularly in coastal areas. The highest levels o hydrocarbons were 1600 yg I” found near Bahrain compared with background level of 10 to 15 yg I’. Oil washed ashore at Pensacola Beach, Florida, from the DWH spil resulted in weathered oil petroleum hydrocarbon concentrations in beach sand ranging from 3.1 to 4,500 mg kg” (Kostka et al., 2011).
4. Significant environmental aspects in relation to offshore hydrocarbo installations.
Drilling operations may require the use of many chemicals. In the OSPAR region chemicals are categorised in four colour classes depending on degradability, octanol water coefficient and toxicity. The green category means it “shall pose little or n risk to the environment”. Chemicals in the black category should be prohibited an chemicals in the red category should be substituted. Chemicals in the yello category have characteristics between the red and the green class and ar considered to be environmentally acceptable.
Other operational discharges are drill cuttings and small spills of oil and chemical connected to exploration, production or transport.
For the offshore industry in the North East Atlantic, OSPAR has agreed on severa decisions and recommendations to reduce discharges of oil and chemicals. Thes include Recommendation 2001/1: Management of PW and 15 per cent reductio target for oil discharged with PW, in addition to agreements on decisions an recommendations for use of chemicals offshore, decommissioning an environmental management (OSPAR, 2010).
OSPAR reports discharges, spills and emissions from oil and gas installations Between 2001 and 2007 an average of between 400 and 450 million m? yr* PW wer discharged (OSPAR 2009). For 2010 a sum of 361 million m? PW was discharged i this area. The main contributing countries were Denmark (25 million m*), Norwa (131 million m3) and United Kingdom (196 million m?; OSPAR, 2010). The number account for the whole OSPAR region, but the main region of activities is the Nort Sea. Oil content in PW was reported as dissolved and dispersed oil, and annua average oil content was reported to be 12 and 13 mg/l, respectively. Annual averag oil content in dissolved and dispersed oil was 4,227 tons and 4,746 tons respectively, giving a total of 8,972 tons in 2010. Annual quantity of injected PW was
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81 million m?(OSPAR, 2012a). Yearly discharge of approximately 400 million m? P has been relatively constant since 2001 (OSPAR, 2010).
Most of the concern regarding negative effects on ecosystems due to operationa discharges from offshore oil and gas activities has been directed to the oil fraction o PW discharges, and less towards the added chemicals. This is due to the content o polycyclic aromatic hydrocarbons (PAHs) and alkylated phenols from the oil fraction PAHs have received focus because they can be metabolically activated in fish an bound to DNA as DNA adducts. PAHs are also shown to damage early developmenta stages of fish creating several effects at low doses, including effects on hear development (Incardona et al., 2004; Brette et al., 2014). Alkylated phenols hav received focus because some of these compounds have hormone-mimicking effect (Heemken et al, 2001).
Norway monitors the levels of contaminants in sediments, deployed fish and mussel and in wild caught fish, in addition to effect studies in fish and mussels. Monitorin of sediments shows very small areas with increased total hydrocarbon content o disturbed fauna. Mussels and fish deployed in cages for 6 weeks around differen platforms did not show effects in distances further than 1 km (Brooks et al., 2011) No increased levels of contaminants were found in fillets of wild caught fish although in some cases wild caught fish had increased levels of PAH metabolites i bile. The most surprising findings have been levels of DNA adducts in haddock live from the North Sea, at levels giving rise to environmental concern in 2002 (Balk e al., 2011) and in 2011 (Gr@svik et al., 2012) because the levels were above th environmental assessment criteria (EAC) for DNA adduct in haddock liver (ICES 2011).
5. Gaps in capacity to engage in offshore hydrocarbon industries and to asses the environmental, social and economic aspects.
The hydrocarbon industry is an extremely technical endeavour and it has evolve over a period covering more than 70 years. The offshore industry must deal with th fact that the hydrocarbon resource lies hidden, often several kilometres beneath th seafloor. Therefore, the industry employs highly skilled specialists and advance technologies to image and sample the seafloor to find the hidden hydrocarbons. I general, oil and gas resource development requires the deployment of considerabl technology to access, control, and transport the hydrocarbons.
In many parts of the world, massive oil revenues have not overcome high levels o poverty. Indeed, in some cases, they have led to significant social problems. Man oil and gas companies do not publish information what royalties, taxes and fees the pay country by country, and there is thus often a lack of transparency about thes transactions. (FESS, 2006; Ross, 2008).
Only 80 out of the known 974 sedimentary basins on earth contain exploitabl hydrocarbons (Li, 2011). Therefore, huge risks and uncertainty are inherentl associated with hydrocarbon exploration activities. Many “dry” exploration wells ar drilled for every winner (for example, see BSEE web site). The industry invests
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expertise, money and time to reduce risk and uncertainty so that the maximu amount of hydrocarbons is found with minimum effort and investment.
Exploration and production companies are international and operate wit sophisticated technologies to make discoveries, across international boundarie wherever hydrocarbons may be found. Individual fields may cross internationa boundaries, further complicating their development and adding risk to investors; th Timor Gap, an area of disputed seafloor located on the border between Australi and Timor-Leste is a good example (Nevins, 2004).
In the initial stages of their development, many oil-endowed countries lacked th highly specialized knowledge or the substantial funds required to successfully fin and produce offshore hydrocarbons. So, offshore hydrocarbon exploration became  primarily private-sector activity worldwide, dominated by international oi companies with the relevant skills, experience and finances needed to take o significant risk.
Over the past few decades there has been a significant shift in ownership of th offshore oil and gas global enterprise. In the 1970s, 85 per cent of all offshore oi reserves were owned by seven international oil companies (IOCs). By 2012, 18 o the top 25 oil and gas producers were National Oil Companies (NOCs), controlling 7 per cent of oil production and holding 90 per cent of the world's oil reserve (Wagner and Johnson, 2012). NOCs have competed with IOCs developing ne technologies and productive resource capacity to potentially overtake the larges IOCs in size and scope. NOC’s like Brazil's Petrobras, Malaysia's Petronas an Norway's Statoil have specialized in deepwater drilling technologies, onc monopolized by the IOCs (Wagner and Johnson, 2012). This is an example o technology transfer that has benefitted developing countries by allowing them t participate in (if not dominate) the offshore oil and gas industry.
Assessing the environmental impact of offshore oil and gas development i developing countries has not progressed at the same pace as the capacity to develo and exploit the resource. In its assessment of environmental governance in 27 oil producing developing countries, the World Bank (2010) found there was a “lack of  sufficiently organized administrative structure that enables efficient regulator compliance and enforcement. Additionally, the human and financial resource needed for effective environmental governance are generally lacking.” A case stud from Trinidad and Tobago published by Chandool (2011) illustrates the key issues paucity of accessible data, lack of public participation, lack of post-approva enforcement and lack of quality control in environmental impact assessment (EIA practice.
In Malaysia, companies are required to complete an EIA that is prepared by  registered consultant (Mustafa, 2011). The industry was found to have breached it license to operate in 28 cases that went to court in 2009, with fines totalling Ringgi Malaysia (RM) 250,000 (about 76,000 dollars or an average fine of 2,700 dollars) Given the overall value of the industry (Petronas alone had a net worth in 2012 o over 157 billion dollars and had nearly 40,000 employees), there is a prima facie lac of proportion between the potential damage from the offences and the deterren level of such fines.
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More broadly, there are gaps in monitoring the offshore oil and gas industry by th responsible government departments. It has already been mentioned abov (Section 2.4) that the collection of information on offshore pipeline failures is no coordinated in the Gulf of Mexico between state and federal jurisdictions (NRC 1997). The data that are collected by government departments charged wit monitoring the offshore oil and gas industry are often incomplete or not strategic For example, PARLOC (2001) notes that whilst corrosion has been identified as on of the major causes of leaking pipes in the North Sea, corrosion protection data ar not currently recorded in the pipeline database, so it is not possible to derive failur rates for specific types of corrosion prevention. The lack of coordination betwee different agencies having a share of responsibility in managing the offshore oil an gas sector was identified as a key issue by the Australian Government’s Montar Commission of Inquiry Report (2010), whose conclusion was: “A single, independen regulatory body should be created, looking after safety as a primary objective, wel integrity and environmental approvals. Industry policy and resource developmen and promotion activities should reside in government departments and not with th regulatory agency. The regulatory agency should be empowered (if that is necessary to pass relevant petroleum information to government departments to assist the to perform the policy roles.”® Thus, there is a gap in the capability of the responsibl government departments to collect and share relevant information among differen departments and authorities.
Another gap is with respect to the capacity for local communities to engage with th offshore oil and gas industry in decision-making. As has been already noted abov for Trinidad and Tobago, lack of public participation in environmental impac assessments is a clear capacity gap (Chandool, 2011). The Australian company Santos, engaged with local communities in Indonesia’s Jawa Timur Province, wh were concerned with the impact of offshore oil activities on their coastal habitat (Anggraeni, 2013). Although the community expressed concerns over Santos’ ai quality risk management and employment opportunities for local people, a dialogu was established allowing for a more satisfactory outcome for the local communit (Anggraeni, 2013).
8 Partly in response to this conclusion, the Australian Government established, on 1 January 2012 the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA http://www.nopsema.gov.au), to be the national regulator for health and safety, well integrity an environmental management for offshore oil and gas operations.
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Figures
——~ Active (25,711 mi. ——— Out of Service (18,293 mi. ~~ Proposed (1,087 mi.)
The boundaries and names shown and the designations used on this map do not imply official endorsement or acceptance by the United Nations.
Figure 1. Map of offshore oil and gas pipelines in the United States section of the Gulf of Mexico (fro NOAA). http://stateofthecoast.noaa.gov/energy/gulfenergy.html.
(© New cncreres cl cand om bat 7‘ poe 2000 Inet yet 8 presen)
The boundaries and names shown and the designations used on this map do not imply official endorsement or acceptance by the United Nations Figure 2. Offshore oil and gas fields under exploitation, new discoveries not yet in production and
pipelines in the North Sea in 2009. Figure taken from OSPAR, 2010 (http://qsr2010.ospar.org/en/chO7_01.html).
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Onshore ™ Shallow Water ™ Deep Water
83       _ —  ——        l Le     a |
Million barrels per da yw B 6 6 6 6
 °
Sources: infield Systems, BP Statistical Review 2014
Figure 3. Global crude oil production, comparing onshore, shallow offshore (<100 m water depth and offshore deep (>100 m water depth) production (from Infield, 2014).
Whereas onshore production has remained stable at around 50-60 million barrel per day since the early 1970s, offshore production has grown steadily over the las four decades. Deep water production has accounted for nearly all growth sinc about 2005.
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