Horizontal drilling
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Horizontal drilling allows operators to access oil and natural gas reserves that are not directly below a drilling site. Horizontal drilling can access underground reserves that cannot be reached through conventional vertical drilling. The practice became more common during the 1980s due to technological advancements.[1][2][3]
Background
Horizontal drilling is used to extract oil or natural gas located in reserves that span horizontally underground. A vertical well must be drilled before operators can conduct horizontal drilling. To determine how far a driller must go to access energy-intensive reserves, a vertical well is drilled. Geologists then examine the rock fragments at different depths to determine where horizontal drilling should begin. The spot that is determined at a particular depth for drillers to begin horizontal drilling is known as a kickoff point. Drillers then create a horizontally curved hole to access oil or natural gas within the rock formation.[4]
Horizontal drilling is used to access natural gas particularly in shale rock and shale plays, which are found throughout North America. Major U.S. shale plays include the Barnett Shale in Texas, the Fayetteville Shale of Arkansas, the Haynesville Shale of Louisiana and Texas, and the Marcellus Shale in Appalachia, which includes West Virginia and Pennsylvania. Drillers must recover natural gas from small pore spaces within shale rock. Operators drill horizontally through shale rock and use hydraulic fracturing (also known as fracking) and frac sand to prop open the pores. This results in the extraction of more natural gas than would have been extracted through vertical drilling.[4]
See also
Footnotes
- ↑ United States Geological Survey, “The Marcellus Shale Gas Play Geology, Development, and Water-Resource Impact Mitigation,” accessed January 28, 2014
- ↑ FrackWire, “Drilling technology,” accessed January 28, 2014
- ↑ The Denver Post, "Energy companies map Niobrara formation for its oil potential," April 10, 2011
- ↑ 4.0 4.1 Geology, "Directional and Horizontal Drilling in Oil and Gas Wells," accessed April 7, 2017
