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The Appalachian Basin has a well-established history of shale-gas development ([[:File:M97Ch4FG1.jpg|Figure 1]]). The discovery and commercial use of gas from Devonian shales in the early 1820s in Fredonia, New York, is generally recognized as the birthplace of the natural gas industry. This significantly predates the Drake oil discovery in Titusville, Pennsylvania, in 1859. By 1860, a series of shallow shale-gas fields were developed in a fairway along the Lake Erie shoreline extending from Fredonia, New York, southwest toward the city of Sandusky, Ohio.<ref>Harper, J. A., 2008, The Marcellus Shale: An old “new” gas reservoir in Pennsylvania: Pennsylvania Geology, v. 38, no. 1, p. 2–13.</ref> Accurate data for these wells are scarce, but the likely black shale formations produced include the Dunkirk, Rhinestreet, Middlesex, and to a lesser extent the Marcellus. The initial reported gas rates were commonly high, but actual production rates and pressures were low and are not considered commercial by today's standards. These shallow wells were used mainly for domestic and light industrial purposes and were extensively developed from the 1860s through the mid-1900s.

The Appalachian Basin has a well-established history of shale-gas development ([[:File:M97Ch4FG1.jpg|Figure 1]]). The discovery and commercial use of gas from Devonian shales in the early 1820s in Fredonia, New York, is generally recognized as the birthplace of the natural gas industry. This significantly predates the Drake oil discovery in Titusville, Pennsylvania, in 1859. By 1860, a series of shallow shale-gas fields were developed in a fairway along the Lake Erie shoreline extending from Fredonia, New York, southwest toward the city of Sandusky, Ohio.<ref>Harper, J. A., 2008, The Marcellus Shale: An old “new” gas reservoir in Pennsylvania: Pennsylvania Geology, v. 38, no. 1, p. 2–13.</ref> Accurate data for these wells are scarce, but the likely black shale formations produced include the Dunkirk, Rhinestreet, Middlesex, and to a lesser extent the Marcellus. The initial reported gas rates were commonly high, but actual production rates and pressures were low and are not considered commercial by today's standards. These shallow wells were used mainly for domestic and light industrial purposes and were extensively developed from the 1860s through the mid-1900s.

The first major shale discovery in the Appalachian Basin was in 1921 in northeastern Kentucky, which established the Big Sandy field. To date, a total of more than 21,000 wells have been drilled in the Big Sandy field in eastern Kentucky, southern West Virginia, southern Ohio, and southwestern Virginia. The primary target in the Big Sandy field is the Upper Devonian Huron Shale, with contributions from the Cleveland, Rhinestreet, and Marcellus Shale intervals. Two characteristics of the Big Sandy field are its significant underpressured profile and a well-established open natural fracture network. This distinguishes the Big Sandy field from modern shale plays such as the Barnett, Fayetteville, and Haynesville shales, which have higher pressure gradients combined with lower density open natural fracture networks. These modern shale-gas plays rely more on the creation of induced artificial fractures to achieve commercial production rates than production from existing open natural fractures. To date, more than 2.5 tcf has been produced from the Big Sandy field,<ref name=Dw1986 /> and it still represents one of the top 100 gas fields in the United States. The development of the Big Sandy field continues using both vertical and horizontal drilling.<ref>Morris, L. J., 2008, [http://www.papgrocks.org/morris_p.pdf Horizontal development in the Appalachian Basin Devonian shale]: AAPG 2008 Eastern Section Meeting (abs.).</ref>

The first major shale discovery in the Appalachian Basin was in 1921 in northeastern Kentucky, which established the Big Sandy field. To date, a total of more than 21,000 wells have been drilled in the Big Sandy field in eastern Kentucky, southern West Virginia, southern Ohio, and southwestern Virginia. The primary target in the Big Sandy field is the Upper Devonian Huron Shale, with contributions from the Cleveland, Rhinestreet, and Marcellus Shale intervals. Two characteristics of the Big Sandy field are its significant underpressured profile and a well-established open natural [[fracture]] network. This distinguishes the Big Sandy field from modern shale plays such as the Barnett, Fayetteville, and Haynesville shales, which have higher pressure gradients combined with lower density open natural fracture networks. These modern shale-gas plays rely more on the creation of induced artificial fractures to achieve commercial production rates than production from existing open natural fractures. To date, more than 2.5 tcf has been produced from the Big Sandy field,<ref name=Dw1986 /> and it still represents one of the top 100 gas fields in the United States. The development of the Big Sandy field continues using both vertical and horizontal drilling.<ref>Morris, L. J., 2008, [http://www.papgrocks.org/morris_p.pdf Horizontal development in the Appalachian Basin Devonian shale]: AAPG 2008 Eastern Section Meeting (abs.).</ref>

===Development of the Marcellus Shale Play===

===Development of the Marcellus Shale Play===