"Increases in the price of crude oil that began in 2004 pushed the spot price of West Texas Intermediate (WTI), a key oil in determining market prices, to nearly $100 per barrel in the third quarter of 2007. Tight market conditions persisted through the remainder of 2007, with demand growth in China, India, and other parts of the developing world continuing. Uncertain supply related to political unrest in Nigeria, Venezuela, Iraq, and other places continued to threaten the market and contribute to a psychology that pushed up prices. The decline of the value of the U.S. dollar on world currency markets, as well as the investment strategies of financial firms on the oil futures markets, has also been identified by some as factors in the high price of oil. The profits of the five major integrated oil companies remained high in 2007, as they generally accounted for approximately 75% of both revenues and net incomes. For this group of firms, oil production led the way as the most profitable segment of the market, even though oil and gas production growth was not strong. The refining segment of the market performed relatively poorly. Independent oil and natural gas producers are small relative to the integrated oil companies, and their financial performance was weaker, with more than half of the firms reporting declines in net income."
CRS Report for Congress, RL34437
United States. Department of State, Foreign Press Centers, Bureau of Public Affairs: http://www.fpc.state.gov/