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4 History of Oi' and Gas Activities The Inupiat used oil and gas seeps for fuel in Arctic Alaska long before the first whalers or other outsiders ven- tured to the North Slope. Active industry exploration began in the late 1950s when federal geological studies supported the premise that a significant reserve potential existed, and the land was released for industry leasing. By 2001, oil development on Alaska's North Slope con- sisted of 19 producing fields and a network of roads, pipe- lines, and power lines that connect drill sites, production fa- cilities, support facilities, and transportation hubs. Most of those facilities were in place before 1988, by which time the rate of growth had declined because of the full development of the large Prudhoe Bay and Kuparuk oil fields and as a result of changes in technology. TABLE 4-1 Oil Exploration and Development on the North Slope Highlights of the North Slope's oil and gas exploration and development history are summarized in Table 4-1. Ap- pendix C is a more thorough description. Maps depicting active leases (Figure 4-1) and explora- tion wells (Figure 4-2) indicate where industry interest, in- tensity of exploration, and infrastructure have been concen- trated, but both leasing and exploration have covered additional areas not mapped. During the 1990s, interest ex- panded from the Prudhoe Bay area to the west into the Na- tional Petroleum Reserve-Alaska and offshore. More re- cently, leasing has moved south into the foothills of the Brooks Range and in the Point Thompson area. The Prudhoe Bay oil field was established in 1968 with a small airstrip, a camp, and a peat road to an exploration Before recorded history Visible oil seepages used by Native inhabitants of the North Slope 1882 U.S. government representatives hear of oil seepages while traveling in the area 1886 First non-Natives see seepages at Cape Simpson 1909 First description of Cape Simpson deposits published 1914 First oil-related claim staked 1921 Additional claims staked by individuals and industry 1921 Large deposits of oil discovered in Oklahoma and Texas; industry loses interest in the remote Arctic 1922 First industry-sponsored geological investigation of North Slope oil potential 1923 Naval Petroleum Reserve No. 4 (PET-4) established 1923-1926 First analysis of Naval Petroleum Reserve-4 potential 1943 Territory of Alaska Bureau of Mines sends field party to the North Slope to investigate oil and gas seepages 1944 Start of PET-4 petroleum exploration program. PET-4 headquarters established at Barrow Land north of the drainage divide of the Brooks Range withdrawn from public entry by the secretary of the interior, Public Land Order 82 1945-1952 Numerous geophysical studies conducted across PET-4 find oil and gas 1947 Office of Naval Research establishes Arctic Research Laboratory 1953 National Petroleum Reserve-4 unexpectedly recessed 1953-1968 Federal geologic field studies continue in National Petroleum Reserve-4; several major oil companies begin exploration 1957 Oil discovered in Cook Inlet (south-central Alaska) 32

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HISTORY OF OlL AND GAS ACTIVITIES 33 TABLE 4-1 continued 1958 Public Land Order 82 modified; federal leasing begins on the North Slope; first industry-sponsored geological field programs; Alaska Statehood Act passed 1962 First industry-sponsored seismic program 1963-1967 First industry exploration well drilled on the North Slope; 11 unsuccessful wells drilled; industry interest in the North Slope wanes 1964 First State of Alaska lease sale on the North Slope 1965 Area that eventually includes Pru&oe Bay leased 1967 Initial exploratory drilling at site that would become Pru&oe Bay field 1968 ARCO announces the discovery of Pru&oe Bay oil field, the largest in North America 1969 Kuparuk, West Sak, and Milne Point fields discovered; lease sales suspended on the North Slope for the next 10 years because secretary of the interior imposes freezes due to Native claims 1970 National Environmental Policy Act passed 1971 Alaska Native Claims Settlement Act passed 1974-1976 Federally sponsored exploration along the Barrow Arch 1976 Naval Petroleum Reserve-4 is transferred from the Navy to the Department of the Interior and renamed the National Petroleum Reserve in Alaska; sale of crude oil from Petroleum Reserves 1, 2, and 3 authorized 1977 Trans-Alaska Pipeline system operational 1979 Initial leasing of portions of state and federal outer continental shelf (OCS) waters of the Beaufort Sea 1980 Alaska National Interests Land Conservation Act passed 1981 First OCS exploration well drilled 1982 Initial leasing of portions of the National Petroleum Reserve-Alaska 1984-1985 Seismic exploration of the Arctic National Wildlife Refuge 1002 Area conducted 1985 First industry exploration well drilled in the National Petroleum Reserve-Alaska 1986 Arctic Slope Regional Corporation well drilled within the coastal plain of the Arctic National Wildlife Refuge Various times Initial leasing of portions of Arctic Slope Regional Corporation lands Early 1990s Last of the National Petroleum Reserve-Alaska leases from the initial leasing program are relinquished 1994 Discovery of Alpine field 2001 Northstar field begins production Development of Liberty field suspended ! E: .3~ r ~ E ~~ EN EN ~ ~ ~ ~ ~ ARCTIC Oc~x \ :~ ~ ~ ~ ~ i~ ~ :t $ 3 ~ ~ ~ BARRY Year Sold/ Leases - - . . ~ ~ ~ ~ >-~ ~ ~ . Issued Remaining ~ j ~ ,~ ,~\~ ~3 ~ ~ . _1950s 2 ~ ~ ~ ~ --r~~ \ /' ~ ,: , ~ ~ ~ ~ ~ _ 2~' ~ ~ ~~ .', ~ at'' i ~ Nylon u peiroleurn Resenre Atasla - ? {I' ~o.~ wreathe F,ef09~ POINTS ' ~ ' ' .'' -, - , . ~ ~ ~ ~ ., - - ' ' ~ ' -'a O ~ ~ ~ ~ 1 00 :. ~~ ~~ ~ ~~=~ ~ ~~ ~ ~ -- ~ I-::: Get_ ut the A=e N# ~ FIGURE 4-1 Time of acquisition of current leased lands on the North Slope of Alaska. The leases acquired during the l900s are shown by decade and those since 2000 are depicted by year. The age of the leases indicates the recent shift in exploration interest to the south and west. Earlier leases that have been relinquished are not shown. Funded by the National Academies. Drawing by Mapmakers Alaska, 2002.

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HISTORY OF OIL AND GAS ACTIVITIES well (Figure 4-3~. The only permanent structures in the area before those were the distant early warning line facilities at Point Strokerson and Oliktok, and a few sod houses built by the Inupiat. By 1970, after the confirmation of the Prudhoe Bay oil field, airstrips, roads, and other gravel infrastructure were built or expanded to connect distribution centers to camp facilities and remote drilling sites. The growth of this development is shown in Figures 4-4, 4-5, and 4-6. An im- portant milestone was the completion of the North Slope Haul Road, eventually called the James Dalton Highway, which formed the work path for constructing the Trans- Alaska Pipeline and links Prudhoe Bay to the outside world. To the west, the Kuparuk oil field road network began to expand in 1978. The average length of roads added each year during expansion (26.1 km [16.2 mill (Walker et al. 1986a) was similar to that at Prudhoe Bay (22.5 km [14 mill (Walker et al. 1986a), although gravel pads at Kuparuk were smaller and spaced farther apart than were those at Prudhoe Bay. After 1977, gravel mining in upland tundra sites re- placed floodplain scraping as the source of roadbed material. Those deeper mines reduced the area of disruption caused by mining, and the effects on diverse riparian systems were re- duced as a result. ANATOMY AND OPERATION OF NORTH SLOPE OIL FIELDS Oil-field operations on the North Slope involve four dis- tinct but closely related phases: leasing, exploration, devel- opment, and production and transportation. We present these sequentially for clarity, but they can occur out of sequence. For example, seismic exploration can occur before leasing or during the development phase. Each phase has unique elements and some that are shared with other phases. The result is the complex diagrammed in Figure 4-7. Leasing Mineral rights, or the right to extract resources from beneath the ground, are sometimes, but not always, attached to the ownership of the surface area. Either way, clear title to mineral rights must be obtained through purchase or lease.) When rights are owned by a public institution, such as a state or the federal government, the leasing process is public, and it usually is preceded by announcements of lease sales and by competitive bidding. Information concerning leas- ing, or even potential leasing and development, usually af- fects various interested parties. ~ On the North Slope, most oil production is on state lard; leasing arid exploration mostly occur on state arid federal larld. Some leasing, exploration, arid production occur on Native lard. The Arctic Slope Regional Corporation has subsurface mineral rights in some areas. The Beaufort Sea out to three miles is under state control; beyond that it is federal. Northstar is the only facility currently producing oil in federal waters off the North Slope. 35 Exploration Exploration, the most widely dispersed activity, leads to development and production when economically develop- able quantities of oil or gas are discovered. Historically, such quantities have been found 10-20% of the time in "frontier" areas and as much as 60-70% of the time in mature areas near established fields. Seismic Exploration Unless a well is in a previously tapped reservoir, one or more seismic surveys usually are conducted before drilling begins. An initial summer survey of a proposed area is fol- lowed by winter surveys that use vibrating equipment and receivers placed on the tundra along a rectilinear grid. The vibrators generate sound waves that bounce off underground rock. The returning sound is picked up by the receivers and analyzed and mapped by computers. Mobile survey camps responsible for collecting seismic data are typically moved by D-7 Caterpillar tractors, although some of the tractors have been replaced by roller-tracked vehicles. Support vehicles shuttle to permanent facilities to deliver fuel and supplies. Land-based two-dimensional (2-D) and three- dimensional (3-D) seismic surveys are done in winter when the tundra is frozen and snow-covered and when most ani- mals have left an area, are in maternity dens, or are hibernat- ing. Three-dimensional seismic lines usually are spaced a few hundred meters (several hundred feet) apart in grids. Lines in 2-D grids are spaced up to 10 km (6 miles) apart. Today, 2-D surveys have been largely replaced by 3-D data acquisition. Because of the vulnerability of the tundra to dis- turbance of the organic mat and underlying permafrost, these off-road surveys have been restricted by the Alaska Depart- ment of Natural Resources. Seismic exploration is permitted when the ground is frozen to an average depth of 30 cm (12 in.) and when snow depth averages 15 cm (6 ink. From 1990- 2001, 24,938 km (15,499 mi) of seismic lines was surveyed in northern Alaska. Offshore vessels cruise similar grid patterns during the ice-free season, using high-pressure airguns instead of vi- brators to generate sound waves. In the intermediate area of land-fast ice, seismic data often are acquired during winter with land-based instruments. Exploratory Drilling After seismic surveys indicate that commercially fea- sible quantities of oil or gas are present, exploratory drilling begins. Today, onshore exploratory drilling is a winter activ- ity based on ice roads and ice drilling pads; no permanent structures are built. In remote locations, an ice airstrip is built so that people and supplies can be flown to the site. In areas where prospects are closely spaced, or where confir-

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36 mation wells are required, a single rig can drill 2 or 3 wells in a season. A typical exploratory well requires 14-45 days to dell. Large amounts of water are used in these operations. Dnlling a single exploratory well can use 5.7 million L (1.5 million gal); another 1.4 million L (360,000 gal) generally ; ; i;.; ;.; ; ;. ; ; . .; ; .... .... ......... K~4LUBIIT CREEK TO KUPARUK RI\IER ;; .; ; .. .; .... ..... . CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS would be required for camp use. The Bureau of Land Man- agement estimates that 3.8 million to 5.7 million L (1 to 1.5 million gal) of water is needed per mile to build an ice road 15 cm (6 in.) thick and 9-11 m (30-35 ft) wide (USACE 1998~. Ice roads can extend for many kilometers, and they are increasingly used as a less expensive and less environ- CALCULAT~ONS OF AREA AFFECTED BY OIL FIELD DEVELOPMENT NORTH SLOPE, ALASKA YEAR 1 968 0 10 20 miles ,: ., . _ ........ . . Limit of Map Analysis Study Area ., 1 " '' ' ' ' FIGURE 4-3 Road network for oil-field development, 1968. Area calculations were obtained from topographic maps and historical aerial photography provided by BP Exploration (Alaska) Inc. Funded by the National Academies. Interpretation and calculation were done by Ken Ambrosius, Aeromap USA, 2002. . -I ~ ; - ~ ; ~ .... . WISST)F K(ALUL3IK CRICK KALUElIK CREEK TO I OCR for page 32
HISTORY OF OIL AND GAS ACTIVITIES ... .. ...... WEST OF KALUBIK CREEK KALUBIK CR:EEK TO KUPARUK HIVER .. CALCULATIONS OF AREA AFFECTED BY OIL FIELD DEVELOPMENT NORTH SLOPE, ALASKA YEAR 1983 CUMULATIVE VIEW An. FIGURE 4-5 Road network for oil-field development, 1983, cumulative view. Area calculations were obtained from topographic maps and historical aerial photography provided by BP Exploration (Alaska) Inc. Funded by the National Academies. Interpretation and calculation were done by Ken Ambrosius, Aeromap USA, 2002. .. ~ ~ . ~ ~ .; ;; .. ~ . I ; ;. ~V~3 1 OF K^LUBIK CHEEK ; KALUBIK CR:EEK TO KUPARUK RIVER ; - ... .. .. - - - . 12' :: CALCULATIONS OF AREA AFFECTED BY OIL FIELD DEVELOPMENT NORTH SLOPE, ALASKA YEAR2001 CUMULATIVEVIEW __) . . ,,,; ., ~ ~~ ::: . 6 ~ :; :.:. :.:..:..:.: .:;: :.: :.: :.:. :.. ;..; ,, :,:, ,, ,, ,., ,, .,..;..;.; .,., I;,, ,,,. ,, ,, ,, ,, , .::,, ,,..;;,; ,, :,:,: .;, ,, ,., ,.,..; Limit of Map Analysis Study Area 7. ~ As; N ~ A .~ FIGURE 4-6 Road network for oil-field development, 2001, cumulative view. Area calculations were obtained from topographic maps and historical aerial photography provided by BP Exploration (Alaska) inc. Funded by the National Academies. Interpretation and calculation were done by Ken Ambrosius, Aeromap USA, 2002. The Trans-Alaska Pipeline and Dalton Highway looking towards the Brooks Range. July 2001. Photograph by David Policansky. 37 mentally damaging alternative to gravel roads. For the win- ter of 2001-2002, 420 km (260 mi) of ice-road building was planned. Offshore, exploration wells are drilled in the winter from ice islands, artificial gravel islands, natural islands, or drill- ing vessels or structures, depending on water depth and dis- tance from the shore. Nearshore exploration including most exploration in state waters can be conducted from existing onshore facilities or from ice pads. Exploratory drilling uses diesel engines to turn a drill bit, which cuts through the surface and the rock beneath. Drilling "mud" or fluid, a thick barite solution with various additives, is pumped down the center of the "drill string" (sections of pipe that are added as the bit descends). The mud returns to the surface in the space between the drill string and the casing for cleaning and re-use or for disposal. Drill mud has three purposes. First, it lubricates the drill

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38 CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS Gas Bar Reinfusion Centm ~ | Gas F8GIIRY Seawater Seawater Treatment Plant Iniisetion Plant Orillsi~ Mel ~ j Pads Central c~pFe"" LoBas Natural ~!35 Liquids ~ ~ oil: ~~' ~rocucoon ~i; 'p~rud~QB Bay Pr~uct'~n ~ ~ ~ ~ ~ ~ - ~ '~.~ ~ f it' ~ .. 1.~ L..~ Lo::::::::: ::::::~r~ ~~- ~ / ~~ inanity ~ Maroon c burns ~ ~ ~ / : :__ ,:.r . . ' .f ~ ~ ellilu~ing rac'''ty stabon ~ 1 / . ~ ~ ~ Seal ~ r ~ ~ ~ Seal , ~ , i._ DISDOSal ~ ~1 Few Led _ NGES (Nature! Gas L1qulds) TAPS (T~ns-P`~ska P'pelir, System,) FIGURE 4-7 Schematic diagram of North Slope oil-field operations. SOURCE: Modified from Alaska Department of Natural Resources, Division of Oil and Gas, unpublished material, 1996. bit. Second, it brings the "cuttings," small pieces of rock that the bit grinds, to the surface. These are filtered at the surface and the mud is re-injected. Finally, the weight of the mud seals the well against pressure that is encountered in the well. Well casings, drill strings, mud, cement, diesel fuel, various types of equipment, and people are all transported to drill sites over ice roads or by aircraft. In remote locations, such as the North Slope, oil-field activities require a concentrated work schedule. Commonly, workers meet and are transported to the drill site, where they stay for 1-2 weeks. Drilling continues around the clock, and two complete crews at the drill site rotate in 12-hour shifts. After 1 or 2 weeks of work, workers generally have time off, usually for the same period as the work cycle. Development Once an economically viable discovery is made, devel- opment begins. This phase involves additional drilling, and so begins construction of roads; airstrips; and waste-disposal, seawater treatment, gas-handling, power generation, storage, maintenance, and residential facilities (Figure 4-8~. Most roads and other permanent facilities must be built on thick gravel pads, and pipelines and heated structures must be el- evated on pilings to prevent thawing of the underlying per- mafrost and subsidence of the ground. Some 954 km (596 mi) of roads, 2,338 hectares (ha [5,777 acres]) of pads, and 116 ha (287 acres) of airstrips are spread across a contained development area of more than 2,600 km2 (1,000 mi2) of the North Slope, an area roughly as big as the land area of Rhode Island, which is 2,707 km2 (1,045 mid. The area covered by gravel is about 3,700 ha (9,200 acres). This does not include the area covered by gravel fill or excavation for the Trans- Oil-production facility, Prudhoe Bay. September 1992. Photograph by David Policansky.

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40 Alaska Pipeline and the haul road on the North Slope or the exploration facilities in the National Petroleum Reserve- Alaska. Offshore gravel islands support production operations. Twenty such islands have been constructed in the Beaufort Sea (ADNR 2001a), including two at Endicott and one at the Northstar site. The Endicott islands are connected to each other and to the mainland by an 8 km (5 mi) causeway and are situated in waters generally less than 2 m (6.5 ft) deep (AOGA 2001~. The 2 ha (5 acre) Northstar island site is lo- cated 6 km (4 mi) northwest of the Pt. MacIntyre field in 12 m (39 ft) of water (BP Northstar 2002~. Oil-production facility, Endicott. July 2001. Photograph by David Policansky. The shallowness of the Beaufort Sea in the Prudhoe Bay prevents large vessels from docking there. Three gravel causeways have been constructed to facilitate docking, to provide access to artificial-gravel production islands, and to draw seawater for waterflooding. The causeways are 335 m (1,100 feet), 4 km (2.5 ml), and 8 km (5 mi) long, respec- tively (AOGA 2001~. Large quantities of gravel are required for building roads and pads and for other purposes. From 1972 on, more than 56 million m3 (73 million yd3) of gravel (ADNR 2001b) was extracted from 24 open-pit gravel mines affecting some 2,546 ha (6,364 acres) of stream and river beds and upland sites on the North Slope (MMS 2001a; G. Schultz, ADNR, personal communication, 2001~. Similarly, construction and postexploration drilling require large amounts of water. Overall, the Alaska Department of Natural Resources (ADNR) estimates that 1.5 billion gal (5.7 billion L) of wa- ter was used by North Slope oil and gas operations in 2000 (ADNR 2000~. Facilities needed during development phase generally are constructed elsewhere, transported to the North Slope on barges in late summer, and then moved by road to the pads. Workers and materials are brought in on the Dalton High- way or by air. CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS Production and Transportation Production and transportation follow completion of de- velopment, but development activities often continue long after production begins. The major difference between this and the previous stages is that large volumes of fluids are handled, transported, and disposed. This phase involves drill- ing wells for enhanced oil recovery or waste disposal and the construction of pipelines to move oil, gas, "produced water" (water, often in very large volumes, that is extracted with the oil from a reservoir), and drilling wastes to the existing trans- portation infrastructure or to injection facilities. To maintain reservoir pressure, water is withdrawn from the Beaufort Sea and injected into oil-bearing formations. Because North Slope natural gas currently is uneconomical to market, gas that is not needed to fuel operations is injected back into the r onglnatlng Iormahon. Production well-heads, Kuparuk. September 1992. Photograph by David Policansky. Until recently, gathering and distribution networks re- quired gravel roads; currently those pipelines are built dur- ing winter via ice roads. All oil produced on the North Slope is fed through gathering lines to the Trans-Alaska Pipeline. The 1,300 km (800 mi) long pipeline leads to a tanker termi- nal in Valdez, on Alaska's south-central coast, from which oil is then shipped to refineries in the lower 48 states and, since 1996, in Asia. On- and off-road vehicles, helicopters, fixed-wing air- craft, and seagoing vessels of various sizes transport equip- ment, materials, and people throughout the life of the oil field. Air, ground, and marine transportation needs are sub- stantial. For example, the construction phase of the Northstar project involved about 35,000 surface trips by bus, truck, and other vehicles. Transportation needs drop dramatically after construction is complete. Power generation and waste disposal continue through- out the life of an oil field. On the North Slope, power is generated by gas-fired turbines and heaters; diesel engines power most exploratory equipment as well as trucks, buses, and heavy equipment. These facilities and vehicles emit sub-

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HISTORY OF OIL AND GAS ACTIVITIES stantial amounts of air pollutants. Oxides of nitrogen (NOX) constitute the largest single category of pollutants emitted. In 1999, oil and gas operations on the North Slope emitted some 70,000 metric tons (t) of NOX per year (ADEC 2002~.2 In 1994-1995, North Slope facilities2 also emitted about 11,000 t of CO, 1334 t of SO2, 5,400 t of particulate matter, and 2,400 t of volatile organic compounds during 1994-1995 (USACE 1999~. Annual CO2 emissions from Prudhoe Bay facilities are estimated3 at 7.3 million t (Jaffe et al. 1995) to Milepost O of the Trans-Alaska Pipeline, Prudhoe Bay. July 2001. Photograph by David Policansky. more than 40 million t (Brooks et al. 1997~. Methane emis- sions have been estimated at 24,000 t (Jaffe et al. 1995~. A final category of emissions is airborne particles, generated by construction activity and vehicular travel on gravel roads, that can significantly affect adjacent tundra. Most North Slope waste is generated in exploration and production activities. More than 76,500 m3 (100,000 yd3) of solid waste is generated by oil-field operations on the North Slope each year (ADEC 2001, BP 1998a). Waste includes oil-contaminated wastes, spill-cleanup materials, batteries, scrap metal, paper and polystyrene waste, tires, construction debris, wrecked vehicles, insulation, old drilling rigs, and food and domestic waste. These wastes are recycled, dis- posed of in the Deadhorse landfill, or incinerated. The North Slope Borough received 74,161 m3 (97,000 yd3) of waste in 2000. The committee did not have enough data to perform additional analyses. 2 Includes emissions from Prudhoe Bay Unit western and eastern operat- ing areas, Milne Point, Endicott, and Lisburne. Does not include Kuparuk, Alpine, Northstar, Badami, or Pt. McIntyre, or any drilling or vehicle emis- sions (U.S. Army Engineer District, Alaska). Current allowable emissions are much higher for CO (18,040 t) and SO2 (2,330 t) (Phillips, personal communication, 2001). 3 Jaffe and colleagues (1995) calculated CO2 emissions based on fuel use data reported to the state by the oil companies. Brooks and colleagues (1997) extrapolated observed emissions during 30 flights downwind of the oilfields. Their estimates were 6 times greater than those in Jaffe' s report, and 4 times greater than total carbon emissions reported by oil facilities for the same months during which measurements were made. 41 Liquid wastes include sewage and domestic wastewater, desalination treatment discharges, and seawater-treatment- plant discharges. No data on the amount of liquid wastes generated by oil and gas operations on the North Slope were available to the committee (ADEC 2001~. Treated sewage and domestic wastewater typically were discharged to tun- dra ponds or to surface impoundments until recently. Desali- nated and seawater treatment wastewater are discharged to the ocean (ADEC 2001~. Waste associated with oil-field exploration, develop- ment, and production includes waste from drilling opera- tions, which generate up to 8,000 barrels (bbl, 300,000 gal, 1.1 million L) of waste muds and "cuttings" per well (BP 1998a); produced water, an average of 1.23 million barrels (51.7 million gal, 196 million L) per day, typically contain- ing a variety of organic pollutants and toxic metals (MMS 2000), usually reinjected; and "associated waste," which is other waste from oil or gas exploration and production- hydrostatic test fluid, oil and oily water, tank-bottom sludge, waste from well workovers and stimulations, pipeline pig- ging waste, and gas dehydration wastes. In addition, the more than 9 t of waste generated each year on the North Slope that qualifies as hazardous, according to the Environmental Pro- tection Agency (EPA) rules, is shipped to disposal facilities in the continental United States (BP 1998a). Generally, wastes are grouped as Class I (nonhazard- ous) or Class II (exempt) and are handled and disposed of in distinct classes of disposal wells. Oil-field wastes asso- ciated with exploration and production were specifically exempted from hazardous-waste regulation by Congress in 1980 (Section 3001 {b)~21(A), Resource Conservation and Recovery Act) regardless of whether that waste would oth- erwise meet EPA's criteria for hazardous-waste classifica- tion. The quantity of those wastes generated on the North Slope is unknown (ADEC 2001~. Most of it is injected into subsurface formations. Class I wastes consist principally of water and are con- sidered nonhazardous. They are largely disposed of through injection into Class I disposal wells (Billington, Shafer, and Billington Environmental Consultants, unpublished material, 1997), of which there are 7 in all, at Alpine, Badami, Prudhoe Bay, and Northstar (Maham 2001~. The volume of fluid in- jected to date exceeds 12 million bbl (1.9 million L, 504 million gal). The principal injection horizons are porous Cre- taceous sandstones at depths of 610-2,400 m (2,000-7,900 ft) that provide well-confined disposal zones. In the western- most portions of the area, the formations are in the perma- frost zone. The Alpine well injects wastes into formations at a depth of about 2,700 m (9,000 ft). Class II wastes come directly from oil or gas wells. They include all produced fluids, muds, and associated wastes that have circulated in the well and solids and ligands that origi- nate down-hole, such as formation water (BP 1998a). Drill- ing muds are water-based materials with clays, weighting materials, and various additives. Cuttings are rock fragments

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42 derived from drilling the well. The cuttings are finely ground and injected with drilling muds. Produced water comes to the surface with oil and gas and must be removed before the oil can be sent to the Trans-Alaska Pipeline. In 1998 (BP 1998a), the volume of produced water was approximately 1.23 million bbl (196 million L, 51.7 million gal) per day comparable to North Slope oil production. Most produced water is treated and re-injected into the reservoir; some is injected into approved disposal wells. The volume of associ- ated wastes at the Prudhoe Bay field is approximately 1 mil- lion bbl (159 million L, 42 million gal) per year (API 1996~. Class II wastes are injected into disposal horizons through 37 Class II disposal wells. More than 1.5 billion bbl (238 billion L, 63 billion gal) of produced water and associated wastes has been pumped into subsurface disposal formations. Until recently, waste materials from the drilling of wells, including muds and cuttings, crude oil, spill materials, and other substances were disposed of in open gravel-bermed ar- eas called reserve pits (BP 1998a) that typically contained from 17 million to 51 million L (4.5 to 13.5 million gal) of waste (ADEC 1985~. There were many problems with reserve pits however, including leaching of contents to the surround- ing tundra. Disposal of accumulated pit fluid on roads for dust control or spilling directly on the tundra also has contami- nated those areas. Studies by the U.S. Fish and Wildlife Ser- vice reported significant effects on water quality in nearby ponds (West and Snyder-Conn 1987, Woodward et al.1988~. Under a consent decree reached between the industry and environmental groups, most old reserve pits in the Kuparuk and Prudhoe Bay fields are being cleaned out and the waste ground and injected into subsurface formations. In addition, ARCO and BP agreed to clean up 170 additional reserve pits as part of the charter agreement governing BP' s acquisition of ARCO (BP Charter Agreement). A grinding and injection plant, the largest of its kind in the world, in- jected some 332,000 m3 (434,000 yd3) of reserve-pit solids in 2000 alone (W. L. Friar, BP, personal communication to Nancy Marks, NRDC, 2/9/2001~. The disposal process requires that porous, water-bear- ing formations below the surface casing accept fluids at pres- sures that will not propagate fractures through the upper con- fining zones. The disposal fluids must be compatible with the formation water, which must not be a potential source of drinking water. CURRENT STRUCTURE OF THE NORTH SLOPE INDUSTRY Historically, oil companies were directly ~ . . . . ~ . . . involved in many of the physical aspects of the location, production, re- finement, distribution, and sale of oil. Gradually, as the scale of oil and gas operations grew, more and more of the activi- ties associated with the oil industry were contracted out to specialized service companies. In general, the major oil com- panies today own or control (lease) the mineral rights to the CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS resource itself (oil or gas), the production facilities, and the pipeline distribution facilities (sometimes through coopera- tive ventures, as with the Alyeska Pipeline Service Com- pany, a consortium of companies that operates the Trans- Alaska Pipeline). Those companies also generally own or contract for other distribution networks (for shipping, for example) and refinery capacity, and they often franchise wholesale and retail distribution. Different service compa- nies generally conduct seismic exploration, drill and com- plete wells, construct production facilities and pipelines, and supply technical experts to address most problems that occur during normal operation (down-hole problems, equipment failures, spills). In turn, many of those contractors subcon- tract to other specialized companies. For example, a drilling contractor could subcontract with other companies to sup- port the drilling operation or provide food service, potable water, drilling mud, casings, drill strings, and even person- nel. Many of those companies contract even further with other support companies that provide additional services. If an exploratory well reveals that the oil or gas is com- mercially feasible to extract, then the oil company will con- tract with fabrication companies to construct the various pro- duction facilities that are needed on land or off shore. In the case of the North Slope, those structures are fabricated in the continental United States or elsewhere in Alaska and shipped by barge to the North Slope during the open-water season. Then, a pipeline company connects the facility to the exist- ing pipeline network, also supported by crews, fuel, water, pipe, and coating. If something breaks down during any of these operations, or if modifications need to be made, addi- tional companies provide specialized services and tools. Once the oil is available for delivery, the oil company re- sumes control to produce and market the product. NORTH SLOPE OIL-FIELD INFRASTRUCTURE The history of the North Slope road and infrastructure network is traced in Tables 4-2, 4-3, and 4-4 and in a series of maps (Figures 4-3, 4-4, 4-5, 4-6~. A full description of the mapping and tabular analyses is contained in Appendix E. The analyses were done by Aeromap, Inc., using informa- tion provided by BP and from other sources. The tables show North Slope oil-field infrastructure history by year and geo- graphic area. Numbers are cumulative. Dashes are used if there were no data for a given year. Figures have been rounded, and may not add exactly in all cases. Exact figures and category definitions are detailed in Appendix E. The development history of the road network and gravel pads was traced in a series of aerial photographs taken in 1968,1973,1988, and 2001. The length of the roads and the area of roads, pads, gravel mines, and some other affected areas were determined for each year. The analysis was di- vided into four major areas: The area between Foggy Island and the Kuparuk

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HISTORY OF OIL AND GAS ACTIVITIES TABLE 4-2 Point Measurements 43 1968 1973 1977 1983 1988 1994 2001 Gravel pads Production pads, drill sites Processing, facility pads Support pads (power stations camps, staging pads) Exploration sites Offshore exploration islands Offshore production islands Airstrips Exploration a~rstnps Culverts Bridges Caribou crossings Landfills o o 1 3 o o 1 o 16 6 36 42 o o 22 10 63 63 2 o 15 62 14 98 103 12 o 16 95 18 108 104 13 2 16 104 18 113 106 13 16 4 4 4 4 4 115 20 115 103 13 4 1,395 17 50 1 TABLE 4-3 Infrastructure Length (Miles) 1968 1973 1977 1983 1988 1994 2001 Roads 0 100 139 294 358 370 400 Peat roads 30 101 101 101 96 96 96 Causeways 0 0 2 3 8 8 8 Tractor trails, tundra scars 19 54 59 57 57 57 56 Exploration roads 0 36 36 36 36 36 36 Total road length 49 290 336 491 554 566 596 Pipeline corridors 1-5 pipes per bundle 366 6-11 pipes per bundle 73 12-17 pipes per bundle 6 18-26 pipes per bundle 4 Total pipeline length 450 Power transmission lines 219 - -r ------ A- - - - ~ - - - - --- - _ _ ___ _ _ _ ~~ 1992. Photograph by David Policansky. River contains the main Prudhoe Bay oil field, Lisburne, Niakuk, Endicott, and several smaller oil fields. This area generally represents the technology used to construct the early oil fields. The area between the Kuparuk River and Kalubik Creek contains the Kuparuk and Milne Point fields and rep- resents an intermediate era of oil-field technology. The area between Foggy Island Bay and the Canning River contains the Badami oil field and a few remote explo- ration sites. The area between Kabulik Creek and the Colville River contains the Meltwater, Tarn, and Alpine oil fields. These and Badami are the newest oil fields, and they repre- sent newer technology. The portion of the oil-field network that is connected by roads stretches to 97 km (60 mi) from the Endicott field in the east to the Tarn oil field in the west. The gravel road network expanded during the past 33 years from a 79 km (49 mi) network of peat roads and tractor trails in 1968 to the current 960 km (596 mi) network of gravel roads and aban- doned roads and trails (Figure 4-9~. Most of the expansion of the road network was done before 1988, the development phase of the field, during which the rate of growth was about 40 km (24 mi) per year. Since 1988, the rate of growth in the road network has been about 5.3 km (3.3 mi) per year. The currently used portion of the network consists of 640 km (400 mi) of gravel roads. About 350 km (215 mi) of the

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44 TABLE 4-4 Infrastructure Area (Acres) (Not Including Dalton Highway) CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS 1968 1973 1977 1983 1988 1994 2001 Gravel roads and causeways Roads 677 1,002 2,029 2,448 2,536 2,745 Causeways 0 48 82 235 229 227 Total gravel road and causeway area 677 1,050 2,110 2,683 2,765 2,971 Airstrips (gravel or paved) 6 136 252 287 313 313 287 Offshore gravel pads, islands Exploration islands 0 0 5 54 57 57 53 Production islands 0 0 0 0 76 92 101 Total offshore gravel pad, island area 0 0 5 54 133 149 155 Gravel pads Production pads, drill sites 0 276 647 2,199 2,917 3,019 3,126 Processing facility pads 0 74 390 692 874 890 917 Support pads (camps, power stations) 14 441 769 1,340 1,444 1,470 1,463 Exploration site 0 109 175 339 317 314 305 Total gravel pad area 14 901 1,981 4,570 5,552 5,692 5,817 Total gravel footprint 20 1,713 3,288 7,022 8,681 8,919 9,225 Other affected areas Exploration site-disturbed area around gravel pad Exploration a~rstnp-thin gravel, tundra scar Peat roads Tractor trail, tundra scar Exploration roads-thin gravel, tundra scar Gravel pad removed, site in process of recovery Gravel pad removed, site is recovered Total other affected area Gravel mines In rivers In tundra Total gravel mine area (acres) 55 o 143 110 o o 308 25 o 25 346 68 547 250 177 1 1,388 4,732 34 4,766 467 68 546 272 179 21 1,552 4,996 151 5,146 613 68 546 263 177 27 1,694 5,011 745 5,756 627 68 520 258 178 46 1,698 5,063 1,179 6,241 650 68 517 258 178 81 1,753 5,061 1,186 6,246 645 67 517 258 177 100 95 1,765 5,082 1,283 6,364 Total impacted area (acres) 353 7,868 9,987 14,472 16,620 16,918 17,354 gravel road network is associated with the Prudhoe Bay oil field and with other fields between the Kuparuk and Sagavanirktok rivers. There is 293 km (182 mi) of road in the oil fields west of the Kuparuk River. The newest exten- sions to the road system have been mainly winter ice roads to link new drill sites in the National Petroleum Reserve- Alaska and elsewhere, but 32 km (20 mi) of new road built since 1998 connects to oil fields southwest of Kuparuk. Ice roads are not shown in Figures 4-3 to 4-6. Information on the history of ice road locations and the total length of ice roads was not available for this report. The total gravel-covered area increased from about 8 ha (20 acres) in 1968 to about 4,000 ha (9,200 acres) in 2001 (Figure 4- 10~. The rate of gravel placement declined noticeably after 1988, because the main road network and most of the pads in the Prudhoe Bay and Kuparuk oil fields had already been built. The average rate of growth was 320 ha (780 acres) per year before 1988 and 23 ha (57 acres) per year after 1988. Most of the gravel-covered ar- eas are associated with onshore drilling and construction pads (2,338 ha [5,777 acres]~. The rest is in roads and causeways (1,204 ha [2,974 acres]), airstrips (108 ha [267 acres]), and offshore gravel pads and islands (63 ha [155 acres]~. Other mapped disturbances include gravel mines (2,575 ha [6,363 acres]) and exploration pads and air- strips, peat roads, and exploration trails (714 ha [1,765 acres]) (Figure 4-11~. Gravel consumption from state lands on the North Slope is shown in Table 4-5. The 1.2 million m3 (1.5 million yd3) mined (5 million yd3 permit- ted) for Alpine from Native corporation lands is not included. There are 115 gravel drill sites or pads, 20 pads with processing facilities, 115 pads with other support facilities (power stations, camps, staging pads), 91 exploration sites, 13 offshore exploration islands, 4 offshore production is- lands,16 airstrips, 4 exploration airstrips, 1,395 culverts, 960 km (596 mi) of roads and permanent trails, 725 km (450 mi) of pipeline corridors (containing 2,720 km [1,690 mid of pipe), and 353 km (219 mi) of transmission lines. The Aeromap analysis did not address the areas indi- rectly affected seismic trails, ice roads, or off-road vehicle tracks nor did it identify the types of terrain that were af- fected by different activity or use. Those issues are discussed in Chapter 7. It also did not cover the Trans-Alaska Pipeline,

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HISTORY OF OIL AND GAS ACTIVITIES 800 - 700 - 600 - 500 - u, .~ 400 300 - 200 - 100 - O- 45 An' at' / , / 1965 1970 1975 1980 1985 1990 1995 2000 Year Gravel roads and causeways Peat roads and tractor trails Total roads FIGURE 4-9 Cumulative history of roads in the North Slope oil fields. Early roads, including tractor trails and peat roads, are indicated with circles. The squares are the existing length of gravel roads. Dalton Highway not included. SOURCE: Alaska Geobotany Center, University of Alaska Fairbanks, 2002. 1 00 00 9000 8000 7000 6000 to 5000 4000 3000 2000 1 000 o a) 1 C,') ' `` I CO ~ a) ' ~ ~ <9 ~ ~ ~ ~ ~ O ~ ~ ~ ~ ~ ~ 0 ~ ~ ~ ~ ~ ~ cut Year Gravel Pads and Islands Al rstrips Roads a nd causeways FIGURE 4-10 History of gravel placement. The area of gravel pads includes all exploration sites, drill sites, production pads, and support pads (camps, power stations). Gravel islands include offshore exploration and production islands. Dalton Highway and Trans-Alaska Pipe- line not included. SOURCE: Alaska Geobotany Center, University of Alaska Fairbanks, 2002.

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46 CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS 200 00 1 80 00 1 60 00 1 40 00 1 20 00 In ,, 1 00 00 8000 6000 400 0 2nnn 1968 1973 1977 1983 Year 1988 1994 2001 1~:1 Gravel m i nes Other distu rbed areas HI G ravel covered areas FIGURE 4-11 History of total disturbed area. The gravel-covered areas portion of each bar is equivalent to total gravel placement in Figure 4-10. Other areas include disturbed areas around exploration sites, exploration airstrips with thin gravel, peat roads, tractor trails, and exploration roads. Seismic exploration trails, ice roads, and off-road vehicle tracks are not included. Gravel placement and the resulting total direct disturbance leveled off after 1988. SOURCE: Alaska Geobotany Center, University of Alaska Fairbanks, 2002. TABLE 4-5 North Slope Gravel Consumption, 1974- 1 yoga Years Permuts Issued Yd3 Permutted Yd3 Extracted 74-79 7 15,408,445 11,415,693 80-84 52 73,312,099 39,218,481 85-89 12 10,767,800 3,640,448 90-94 18 3,328,500 1,254,821 95-99 22 5,704,100 2,326,820 00-01 12 4,384,500 24,218 aTrans-Alaska Pipeline and Haul Road not included; 2000-2001 data in- complete. SOURCE: ADNR (1 yd3 is equal to 0.765 m3) the National Petroleum Reserve-Alaska, and other areas of the North Slope; the analysis is provided as an example where good information is available and where most of the development has occurred. Much of that development used technology no longer in use. RECENT TECHNOLOGY DEVELOPMENTS Over the past two decades, new technologies have been developed and applied to exploration, development, and pro- duction on the North Slope. Some technologies, such as the use of ice roads and ice pads for exploration wells and the Arctic Drilling Platform, are unique to the Arctic and were largely developed in Alaska. Other advances, such as the use of coiled tubing, 3-D seismic-data acquisition, horizontal and multilateral drilling, measurement while drilling, low ground-pressure vehicles (Rolligons), and remote sensing, Alpine field from the air. July 2001. Photograph by David Policansky. were developed elsewhere and adapted for use on the North Slope. Although some of those newer technologies have been used extensively, and the newer fields (such as the one at Alpine) use them almost exclusively, older technologies are still integral parts of the older portions of the Prudhoe Bay and Kuparuk fields. The new exploration-related technologies have reduced the overall use of gravel and presently eliminated it from the

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HISTORY OF OIL AND GAS ACTIVITIES exploration-drilling process, have provided data for better siting of facilities, and have reduced the number of wells required to find and evaluate a new field. Although the physi- cal effects have been greatly reduced by the use of these technologies, there are still valid concerns regarding the po- tential for some amount of damage to the environment. In addition, changing climate might reduce the utility of some newer technologies in some circumstances. The environmental effects of the older road and pad construction techniques and seismic trails are matters of genuine concern. In some instances, the effects have not di- minished with the passage of time; in others, a natural but slow recovery is occurring. The visual impact in some cases will be evident for years if not for decades. The density of 3-D seismic activities can cause short- term visual impact. In areas where there is little snow cover or steep vegetated terrain, damage to the tundra and shrubs can be locally significant and long lasting. Long-term stud- ies of the trails built for the closely spaced 3-D acquisitions are required to document the potential effects. The introduction of newer technologies has reduced the amounts of water and gravel required for some types of operations because of their more efficient well operations and smaller pad sizes. The greater reach of horizontal wells and the use of multilateral drilling reduces the need for large pads and it allows extraction of oil from larger areas; thus reducing the number of pads required to develop an oil field. Because the fields use more effective drilling and fewer wells, the quantities of waste, mud, and cuttings are smaller. Because fuel consumption is lower, there are fewer . . emlsslons. Environmental damage continues to be associated with the use of raw materials and resources, such as gravel and water. And their extraction and use will continue, although at reduced rates per unit of oil recovered, because 3-D seis- mic technology reduces the percentage of dry wells. Also, it is possible that ice pads will be superseded by new types of drilling platforms, and by use of Rolligons. Gravel mining and tundra coverage and water use for ice roads or pads, drilling mud, and the like are expected to continue for the foreseeable future. Any risk associated with well drilling re- mains, although ameliorated somewhat by newer drilling and completion technologies. The possibility of losing a tool downhole, of mud or cuttings spills, and of emissions of air pollutants will continue to exist if to a lesser extent than in the past. A reduction of ground traffic is likely to result in an increase in aircraft movements. Absent new technological advances, the pipelines must be above the ground; if they are buried, they could lose support by thawing permafrost (Chapter 6~. Increasing their elevation has facilitated the movements of caribou, and re- mote monitoring of pipelines has lessened the probability of spills. Remote-sensing techniques have improved early detection and tracking of spills, and have helped with rec- ognition of key habitat for caribou. As a result, facilities 47 could be located to minimize impacts on sensitive caribou populations. Some consequences of using newer technologies also can threaten the environment. Any spills associated with pipelines buried deeply under river crossings would be diffi- cult to clean up and might damage those rivers. There is a remote possibility that injection of waste into subsurface dis- posal zones could contaminate a potential groundwater source, or locally overpressure an interval and result in an escape of fluid to the surface. A poor cement or casing job could provide an avenue of escape for annular injected wastes. The newer technologies have resulted in increased protection for the environment, but they have not eliminated the potential for accidents. Appendix D offers a more com- plete discussion of the technologies and their consequences. HOW OIL-FIELD ACTIVITIES CAN AFFECT THE ENVIRONMENT This section describes briefly how the activities of an oil field can affect the environment. Assessments of the ef- fects of those activities and how they accumulate, which re- quires analyses of the effects on various receptors, are pre- sented in Chapters 6 through 9. Oil and Seawater Spills Accidental spills of crude oil, petroleum products (such as diesel fuel or crankcase oil), and saline water (produced with the oil or seawater used in enhanced oil recovery opera- tions) occur on the North Slope. No large oil spills (more than 1,000 bbl [159,000 L, 42,000 gal]) have occurred on land on the North Slope as a result of exploration and pro- duction operations, although many smaller spills have oc- curred. Three major spills have occurred from the North Slope segment of the Trans-Alaska Pipeline. No major off- shore oil spills have been reported. Many saline water spills have occurred on land. Most crude oil, petroleum products, and saline water spills were confined to gravel pads and roads. Some have affected small areas of tundra, resulting in long-term damage. Spills can occur at and around exploration and produc- tion facilities, pipelines, and pump stations; at support facili- ties, such as storage tanks; and from various vehicles in the area. Oil spills on the North Slope have ranged from 0.006 bbl to 925 bbl (0.98 to 14,703 L, 0.26 to 38,850 gal). Each year from 1977 to 1999 there was an average of 234 spills of crude oil and petroleum products associated with explora- tion and production activities on the North Slope. The an- nual average spill volume was 537 bbl (85,376 L, 22,554 gal). The annual average during that period was 69 spills of crude oil and products associated with the operation of the Trans-Alaska Pipeline from Pump Station 1 to Atigun Pass. The average annual spill volume was 265 bbl (42,132 L, 11,130 gal).

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48 Information on seawater spills is less complete (Maxim and Niebo 2001a). From 1986 through 1999, there were 929 seawater spills associated with North Slope exploration and production and the North Slope portion of the pipeline (up to Atigun Pass). In all, 40,849 bbl (6 million L,1.7 million gal) of seawater was spilled during the period, for an average of 66 spills per year with an annual average volume of 2,918 bbl (463,923 L, 122,556 gal). A detailed analysis of spills, including their causes and frequency, the fate and effects of spilled material, and remediation, is in Appendix G. Seismic Exploration Seismic exploration is usually done by sending sound waves into the substratum and deducing information about its oil-bearing potential based on the speed and strength of the returning echoes. On land, the vehicles that transport the testing equipment can affect the tundra and leave tracks that can persist for years and be visible from considerable dis- tances, especially from the air. Vehicle traffic can disturb donning polar bears and muskox herds. Offshore, seismic exploration can affect the distribution and migration of ma- . . nne amma s. Mining and Reclistribution of Gravel As described above, gravel is used for roads, causeways, pads, islands, and other structures. The gravel is obtained locally, primarily from river beds and gravel pits excavated into the tundra. Its removal and redistribution affect drain- age patterns, flow volumes, melting and freezing of the ac- tive layer, movements of humans and animals, the visual CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS landscape, and snow accumulation. Gravel also kills the veg- etation it covers. Freshwater Use and Redistribution Fresh water is used in the construction of ice roads and pads and in oil fields. An annual average of 4.4 billion L (1,163 million gal, range: 776-1,458 million gal) was used this way between 1996 and 2000 (Table 4-6~. Removing water from lakes can change their character, especially if the water that remains is so shallow that the lake freezes to the bottom. Removal and redistribution of water can affect the organisms that depend on it for habitat, migration, food, and safety (Chapter 8~. Seawater Use and Diversion Large amounts of seawater are withdrawn from the coastal region and injected into subsurface formations to main- tain or enhance pressure in the formation for oil recovery (Table 4-7~. The four existing intakes can remove almost 600 million L (158 million gal) of seawater per day, and between 1996 and 2001, they removed a daily average of 174 million L (46 million gal). Longshore currents have been altered by coastal structures, such as causeways, and those alterations can affect migrations of fish and perhaps other animals. In the summer, onshore seawater spills kill vegetation. Sea Ice Structures Exploration and development in nearshore and offshore waters of the Beaufort Sea require a variety of temporary TABLE 4-6 Quantity (In Millions of Gallons) and Source of Current North Slope Freshwater Use in Established Oil Fields Field, Activity, Source or Operator 1996 1997 1998 1999 2000 Surface water Total surface water Number of lakes Deep wells and other sources Total water use Prudhoe Bay East West Kuparuka Alpinea Milne Point Endicott Badami Northstar BP Exploration 181 132 159 o 38 o o 6 3 519 125 257 776 189 130 78 o 51 o 10 1 36 495 131 606 1,101 112 140 127 150 40 3 22 5 31 630 154 681 95 92 96 244 11 o 9 o 40 587 181 582 1,169 108 61 181 213 28 8 609 174 849 1,458 a Includes exploration. SOURCE: Data compiled by BP Exploration (Alaska), Inc., with assistance from ADNR and Phillips Alaska, Inc.

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HISTORY OF OIL AND GAS ACTIVITIES TABLE 4-7 Intake Capacity and Use of Seawater by North Slope Facilities (Millions of Gallons per Day) Facility Intake Capacity 1996-2001 Mean Prudhoe Bay Unit waterflood Kuparuk waterflood Endicott waterflood Northstar Totals 103.6 28.2 23.5 2.6 157.90 26 13 0.05 46.05 SOURCE: Data compiled by BP Exploration (Alaska), Inc., with assistance from ADNR and Phillips Alaska, Inc. and permanent structures, such as causeways, islands, and drilling platforms. A major concern about causeways is their potential to alter nearshore currents and fish migrations. Drifting ice accumulates on the up-current sides of gravel causeways, islands, and drilling platforms, and areas of open water (polynyas) form on the down-current sides (Stirling 1988a). Gravel structures and grounded ice roads and islands can affect the stability and persistence of shore-fast ice when they serve as anchoring points or cause cracks and leads to form in the ice sheet. Construction, Presence, and Aging of Infrastructure The traffic and noise associated with the construction of infrastructure roads, pipelines, buildings, pads, platforms, airstrips can disturb or alter animal migration. In addition, the presence of structures themselves on the landscape can disrupt migration and thus alter the distribution of organ- isms. The presence of infrastructure affects the amount and distribution of dust and ambient noise; it also affects air qual- ity, either directly (by emissions) or indirectly (by providing a substratum for the movement of emitting vehicles and sup- porting the construction of emitting structures). There are visual consequences as well: The structures change the way the landscape is perceived by residents, visitors, and tran- sients. Finally, roads and airstrips affect the environment by increasing access to it, thus increasing the intensity of the effects of human activities in time and space. As the infrastructure ages or is abandoned, other unin- tended environmental effects can result. Aging increases the likelihood of failure, which can lead to accidental discharges (spills) or to other accidents, such as fires. Abandoned roads and other structures can degrade from melting permafrost and continue to alter the visual environment, especially if the climate continues to warm. Most North Slope oil-field equipment dates from the last quarter of the twentieth century. It will continue to age over the next 25 years, the period of this report's scope. Com- ponents that could fail include pipelines through corrosion, subsurface safety valves, and safety systems to suppress fires and explosions. The older oil-field areas such as Prudhoe 49 Bay will be most susceptible to aging. Thus, age-related maintenance demands will increase as oil revenues from declining oil fields decrease. As an aging field's production declines and the cost of extracting oil increases, the eco- nomic incentive to postpone or eliminate maintenance and replacement will increase. The environmental effects of ag- ing infrastructure will depend on interactions between the economics of declining fields, increased replacement and maintenance costs, the regulatory regime, and other factors equally hard to predict. Transportation Noise and disturbances from water, air, on-road, and off-road transportation of machinery, materials, and people can significantly affect marine and terrestrial animals and people' s experiences in the environment. Waste Disposal Disposal of large amounts of industrial and domestic waste produced by industrial operations can contaminate environments and affect the population dynamics of animals, both positively, by providing food, and negatively, by con- taminating environments. Reclistribution of Wealth Oil and gas activities bring money to the North Slope both directly and indirectly. They provide jobs and tax rev- enues, and they fuel demand for local goods and services. They attract tourists, regulators, government officials, mem- bers of the news media, scientists, and others, and those visi- tors contribute to the local economy. The oil industry had a significant effect on changing the social structure of North Slope communities as they changed from subsistence alone to a mixed subsistence-cash economy. A variety of organi- zations have been established as a result of oil and gas activi- ties the Arctic Slope Regional Corporation, the Kaktovik Inupiat Corporation, and various government departments of the North Slope Borough and communities. Those organi- zations have made, lost, and spent money. Information Dissemination Oil, gas, and related activities disseminate a great deal of information. For example, lease sales are announced, oil finds are announced, and the expected methods of extraction are described; scientific studies are conducted and published; political discussions are held; laws and regulations are con- sidered and passed or rejected. All of this information has profound direct and indirect effects on North Slope residents. The announcement of a lease sale can cause fear of environ-

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so mental damage at the same time it raises expectation of profit from private land sales or an influx of new jobs. As a result, investment decisions, lifestyle changes, and the way peo- ple spend their time and energy can be substantially altered. Scientific studies can confirm or contradict people's opin- ions, knowledge, hopes, and fears. Political discussions CUMULATIVE EFFECTS OF ALASKA NORTH SLOPE OIL AND GAS can change perceptions, behavior, investments, and mental health. These effects of information dissemination even in the absence of physical activity are as real as and often even more important than the direct effects of physical activities such as construction of infrastructure.