Annual production climbed fairly steadily for 110 years until 1970. This was the year that the Prudhoe Bay field was brought on-line through the Alaskan pipel proved reserves Since 1948 the Us has imported more oil each year 105×109bb than it has exported Drilling for oil in the US has been reduced in the last 25 08501801900 1960 1980 200 2020 2080 years because the chances of producing a paying well Figure 2.2 Annual rate of petroleum production in the have become less US, including Alaska. The rectangle at the right has an area representing the 134 billion barrels estimated to remaining for future production Prudhoe Bay oil field is the largest oil field in North America, originally containing approximately 25 billion barrels of oilFigure 2.2 Annual rate of petroleum production in the US, including Alaska. The rectangle at the right has an area representing the 134 billion barrels estimated to be remaining for future production. Annual production climbed fairly steadily for 110 years until 1970. This was the year that the Prudhoe Bay field was brought on-line through the Alaskan pipeline. Since 1948 the US has imported more oil each year than it has exported. Drilling for oil in the US has been reduced in the last 25 years because the chances of producing a paying well have become less. Prudhoe Bay oil field is the largest oil field in North America, originally containing approximately 25 billion barrels of oil. Q∞