Congressional concern over high oil prices, growing U.S. dependence on oil imports, budgetary pressures, and maintenance of the Alaskan oil infrastructure has revived discussion over possibly opening part of the Arctic National Wildlife Refuge (ANWR) to oil and gas exploration and development. That part is a 1.5-million-acre area called the "coastal plain"—the so-called 1002 area. Among the arguments put forward by proponents of opening ANWR is that there would be a much smaller surface impact, or footprint, from the petroleum industry's presence compared with procedures, operations, and equipment discussed in the 1987 Final Legislative Environmental Impact Statement (FLEIS) on the Refuge prepared by the Department of the Interior. Current law prohibits petroleum and gas development in ANWR. Some environmental impact is unavoidable with industry activity. Searching for oil and gas involves drilling into the earth with heavy equipment; and various facilities and other activities are necessary to support such drilling. The downscaling of petroleum equipment and operations and the advanced technological solutions to exploration, drilling, and production difficulties have reduced these impacts, however. Improved exploration and development technologies that have become more widely available include advanced seismic data analysis, ice-based technology, slim hole and high performance drilling techniques, and methods to reduce waste. Such innovation also is a factor in addressing the economic obstacles to finding and developing hydrocarbons. Technological advance has more than doubled exploration success rates and markedly improved drilling and production performance and efficiency. Petroleum industry worker productivity has increased and the industry indicates that the potential impact of oil and gas operations on the arctic environment has decreased. Of course, use of the new technologies in ANWR or elsewhere significantly depends upon the nature of the requirements for exploration, development, and production, and on oil prices. The policy issue of whether ANWR should or should not be opened to oil and gas development is not addressed in this report. For more information on ANWR controversies and legislation, see CRS Issue Brief IB10136, Arctic National Wildlife Refuge (ANWR): Controversies for the 109 th Congress. Similarly, the report does not discuss in detail possible effects on the biological environment of industry operations, or the use of the new technologies in light of regulatory requirements for pipeline construction, spill containment, and reclamation of exploration and production sites. Discussion and analysis of some of these matters can be found in CRS Report RL31278, Arctic National Wildlife Refuge: Background and Issues , by [author name scrubbed] et al. However, to put the technology developments—the focus of this report—in perspective, the report's initial section summarizes some of the concerns expressed by opponents of development in the Arctic National Wildlife Refuge, as well as some of the benefits of ANWR development offered by proponents. Exploration and drilling technologies are discussed next, as exploration is the first step toward commercial production of hydrocarbons. After successful drilling of an exploration well or wells, there are a variety of technological options available to the industry for starting the development of the discovery. Production technologies that make it possible to effectively recover the hydrocarbons will complete the technology discussion. The report also compares the procedures and potential environmental effects described in the 1987 FLEIS report with today's available procedures and their possible impacts. While it can be reasonably argued that advanced arctic petroleum technologies substantially mitigate the environmental impact of oil and gas operations compared with how North Slope Alaska oil was developed originally, it also is contended that the use of natural resources such as gravel and water, the probability of spills, and the loss of wilderness as a result of human intrusion are issues that technology advances cannot address. Gravel would be used in development of the 1002 area—at least for things such as main pads, airstrips, and connecting roads. Mining the gravel might result in local changes in topography; roads may have to be built to transport the gravel to exploration and production sites; and there would be a direct loss of coastal plain habitat due to secondary effects of gravel spray, dust deposition, and altered snow melt and erosion patterns stemming from facility construction and gravel mining. Very large quantities of water will have to be used for various activities, such as drilling, ice road and ice pad construction, and support of camp facilities, including human consumption. Water probably would have to be transported into the area. The long-term effects of winter exploration, drilling, and production operations are unknown. Summer erosion and melting of permafrost may due to the heat generated near productions sites. Tundra may be destroyed around the perimeter of insulated ice pads. Compaction, destruction, and delayed growth of vegetation may occur around ice pad production sites. And even minor spills may cause some destruction of vegetation, contamination of waters, and mortality of small food organisms. Surface disturbances probably would be numerous, with production facilities connected by a gathering network or a system of pipelines to an existing or a future pipeline; and production and related equipment may have to be staged at another location over the summer months, then transported to the field during the winter. The use of ice roads may be limited by hilly topography. On the other hand, oil and gas development of the Refuge, it is argued, could yield possibly significant gains in energy security and economic benefits. Development supporters contend that ANWR oil would reduce U.S. dependency upon foreign petroleum, create jobs in Alaska and elsewhere in the United States, generate tax revenues, extend the economic life of the Trans Alaska Pipeline System, and possibly lower oil prices. These potential benefits are discussed and analyzed at length in CRS Report RL31278, Arctic National Wildlife Refuge: Background and Issues , by [author name scrubbed] et al., and in CRS Report RS21030, ANWR Development: Economic Impacts , by [author name scrubbed] . The petroleum industry has accelerated the introduction and use of new technology for operations in the harsh Arctic environment since 1987, the year the Department of the Interior released the FLEIS with its recommendation to drill in ANWR. Tables 1 and 2 summarize the increasing availability of these technological changes since 1987. Some technologies are reported to have gone from the embryonic stage to the mature stage. Interim stages indicate that technology is characterized by a continuum of application and integration by the industry. Four of the now mature technologies were in early stages of commercialization in 1987. Embryonic and emerging technologies are those first supported by scientific fundamentals and theory, and then introduced to industry as technology. Transfer to and initial testing of the technology by industry characterizes a growth technology. As the technology is used, it may or may not prove to be successful to the industry. If the technology is successful, repeated use establishes a track record. In the appropriate situations, mature technologies become common operating procedures. New exploration technologies ( Table 1 ) give petroleum geologists a clearer picture of underground structures and fluids before drilling begins, and thus reduce the need for exploratory drilling. The use of ice roads during the winter and insulated ice pads during the summer can reduce surface disturbance, and high performance drilling can reduce surface footprint of industry operations and waste generation. Production technology that is more available than in 1987 ( Table 2 ) requires fewer workers, less land, and less waste than earlier production methods. Subsequent sections discuss all of these technologies in greater detail. The North Slope is home to the two largest developed oil fields in North America; and it has the largest oil field discovered in the United States in the last decade. Logistical barriers posed by harsh environmental conditions—such as extremely low temperatures, freezing and thawing of the tundra, and remoteness—have limited but not prevented exploration, drilling, and production in this region. There has been interest in and geological exploration of the petroleum potential of the 65,000-square-mile North Slope coastal plain—11% of the land area of the state of Alaska—since about 1906. Federal exploration of the North Slope can be documented for 50 of the last 80 years, beginning in 1923; and industry exploration has been continuous since 1958. A description of the exploration that has taken place within ANWR in particular is presented in the appendix to this report. The possibility of petroleum in the subsurface was hinted at by the presence of oil seeps and oil-stained rock at the surface. Mining claims were staked on the seeps outside of ANWR in the early 1900s but never fully exploited. Oil seeps and oil-stained rock also were found within the coastal plain of ANWR. From 1944 to 1953, the Navy conducted a program in the Naval Petroleum Reserve #4, now the National Petroleum Reserve-Alaska (NPRA). There, 37 wells were drilled to test 18 structure types that appeared prospective for hydrocarbon accumulation. Three oil and seven natural gas fields, all uneconomic, were discovered. Although uneconomic quantities of petroleum were found, this federal exploration program supported the conclusion that the North Slope had most of the elements of a major petroleum province. The information from the federal exploration program combined with subsequent economic studies indicated that profitable operations could be conducted on the slope despite the remoteness and harshness of the area, and several companies began North Slope exploration in 1958. Three fields illustrate different methods of exploration and development in the Arctic environment. Prudhoe Bay, discovered in 1968 with production starting in 1977, Kuparuk River, discovered in 1969 with production beginning in 1981, and Alpine, discovered in 1994 and placed into production in 2000. Prudhoe Bay is the largest known oil field in North America. In 1968, reserves were estimated at 9.6 billion barrels of oil and 29 trillion cubic feet of natural gas. With advanced technology, estimated original reserves of oil (taking into account past production) have increased to14 billion barrels. With no current economic means of getting the natural gas to markets, there has been little or no incentive to produce gas or pursue reserve estimation. The subsurface hydrocarbon accumulation at Prudhoe Bay spans 125,000 acres.