Unconventional: The Development of Natural Gas from the Marcellus Shale
New technology in the twenty-first century has opened up vast new reserves of natural gas and oil from formerly non-economic resources, primarily organic-rich shale. Production techniques such as horizontal drilling and high-volume hydraulic fracturing have led to the recovery of large amounts of natural gas and oil from formations like the Barnett Shale in Texas, the Fayetteville Shale in Arkansas, the Bakken Shale in North Dakota, and the Marcellus Shale in Pennsylvania and West Virginia. These resources have created a surplus of natural gas, have provided abundant supplies of oil, and have made the United States essentially energy independent for the first time in decades.
Although terms like “fracking” and “Marcellus Shale” have become commonplace, few people realize that the development of the technology that enabled the economic production of these resources had its origins in the oil embargos and energy crises of the 1970s. The U.S. Department of Energy (DOE) funded the Eastern Gas Shales Project in the late 1970s and through the 1980s to characterize the resource potential of the extensive, organic-rich Devonian shales in eastern geologic basins, including the Marcellus, and to develop the engineering technology needed to extract natural gas from these rocks economically. Mitchell Energy pursued this into the 1990s, and their persistence eventually achieved the breakthrough needed to produce commercial amounts of gas from low-permeability resources like shale. The application of greatly improved directional drilling technology developed for deep-water offshore platforms, combined with slickwater hydraulic fracturing, allowed Mitchell to use horizontal boreholes with multiple stages of hydraulic fracturing to engineer high-permeability, fracture flow paths into a sufficient volume of reservoir rock to produce significant amounts of gas from the Barnett Shale.
Other companies followed suit on other formations, with Range Resources achieving the first commercial horizontal Marcellus Shale well in southwestern Pennsylvania in 2007. Range Resources used data and assessments from the DOE Eastern Gas Shales Project to select target intervals in this well, and their competitors also combed through the DOE archives for relevant reports and data. The development of the Marcellus Shale has been largely in two play areas: southwestern Pennsylvania and northern West Virginia, where the shale is a bit thinner, but pipelines are present to receive the gas, and northeastern Pennsylvania, where the shale is thicker, but access to pipelines is not as easy. Estimates of recoverable gas from the Marcellus and other gas shales run to many hundreds of trillions of cubic feet, which should supply the United States with natural gas for decades. Shale gas has completely changed thinking about world fossil energy supplies.
The development of natural gas from the Marcellus and other shales has not been without controversy. Antifracking activists have made claims that shale gas development in general, and hydraulic fracturing in particular, contributes to climate change and threatens groundwater resources, terrestrial and aquatic ecosystems, and human health. Based on these claims, the states of New York and Maryland have banned high-volume hydraulic fracturing on the Marcellus Shale, although it is permitted in Pennsylvania and West Virginia. The actual environmental impacts are neither as extensive nor as persistent as some activists believe, but there certainly are issues. Shale gas development can affect air quality, water resources, landscapes, and ecosystems.
Most of the environmental problems stem from the boom-and-bust nature of the oil and gas business. In their hurry to capitalize on this new resource, exploration and production companies often hired many inexperienced people to install a large number of wells as quickly as possible, resulting in significant impacts. The boom led to an oversupply of gas, causing a drop in gas prices and a slowing of drilling activities. When the bust came, only the most experienced drilling crews were retained, but the damage done during the earlier boom cycle left large numbers of people permanently opposed to “fracking.”
Research is attempting to reduce the uncertainties related to the environmental impacts of shale gas development. Federal interagency studies have been investigating air pollution and greenhouse gas emissions, impacts to water availability and water quality, subsurface migration of gas and liquids, wellbore integrity, geochemistry of produced fluids, impacts to ecosystems, and exposure routes and possible impacts to human health. Many university and research foundation studies are working along similar lines, and efforts are being made to coordinate, collaborate, and reduce duplication of efforts. Research is also being focused on finding new uses for the abundant natural gas being produced from shale. Two suggested utilization technologies are generating electricity and use as a transportation fuel.
The successful development of the Marcellus Shale achieves the long-sought goal of greater energy independence for the United States. It also contributes to an “all-of-the above” energy strategy that utilizes existing resources while continuing to develop new ones.
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New technology has opened vast reserves of "unconventional" natural gas and oil from shales like the Marcellus in the Appalachian Basin, making the United States essentially energy independent for the first time in decades. Shale gas had its origins in the oil embargos and energy crises of the 1970s, which led to government research to increase domestic energy supplies. The first large-scale shale gas production was successful on the Barnett Shale in Texas in the late 1990s, followed a few years later by the Marcellus Shale in Pennsylvania. Shale gas has changed thinking about fossil energy supplies worldwide, but the development of these resources has been controversial. Activists have made claims that hydraulic fracturing may contribute to climate change, threaten groundwater resources, and pose risks to terrestrial and aquatic ecosystems, and human health. This volume explores the geology, history, technology, and potential environmental impacts of Marcellus Shale gas resources.