THE GEOGRAPHY OF TRANSPORT SYSTEMS
Source: adapted from M. Simmons (2008), www.simmonsco-intl.com
Types of Oil and Gas Reserves
The availability of oil resources is correlated with market price and technology, but like many resources quality (often measured in level of concentration) is inversely proportional with quantity. High quality oil and gas resources have mostly been tapped leaving more marginal resources such as tar sands and gas shales to be considered. Still, extracting low quality resources is an expensive and technically intensive endeavor.