known reserves, while considerably smaller than the more speculative estimates of ultimately recoverable resources, is also large. British Petroleum has reported that proved reserves of oil in 2006 amounted to 1390 billion barrels and that proved natural gas reserves were 6263 Tcf (British Petroleum, 2007). World coal reserves were 900 billion tonnes, which is about 300 times the 2006 world coal consumption (British Petroleum, 2007).
Technology plays an important role in turning speculative resources into proved reserves. Sophisticated exploration and production methods for recovery of oil and natural gas are already commercially available, and the private sector is developing advanced versions of these techniques. The cumulative effect of continuing advances in exploration and production technology for oil and gas is that over the next 20 years much of the current resource base will become technically recoverable. (See Table 7.5 for a discussion of this technology.)
As noted previously, world reserves are annually producing about 30 billion barrels of oil and 104.1 Tcf of natural gas. The United States is the third-largest oil-producing country and the second-largest natural gas producer. Nevertheless, this country imports about 56 percent of its oil and about 14 percent of its natural gas.5 Import dependence, especially for oil, creates serious economic and security risks, as global oil and gas supplies may be influenced by restrictions imposed by governments, by the actions of the Organization of the Petroleum Exporting Countries (OPEC), or by disruptions due to political instability or regional conflict. For this reason, the capacity to maintain or increase domestic production is
Virtually all of the natural gas that the United States imports comes from Canada.