Unconventional Oil and Natural Gas Emerging Resources and Select Environmental Issues

The United States has seen a resurgence in petroleum production, mainly driven by technology improvements (hydraulic fracturing and directional drilling) developed for natural gas production from shale formations. Application of both of these technologies enabled natural gas to be economically produced from shale and other unconventional formations, and contributed to the United States becoming the world's largest natural gas producer in 2009. Use of these technologies has also contributed to the rise in U.S. oil production over the last few years. In 2009, annual oil production increased over ...