Directional drilling is a way of drilling a well that is purposefully non-vertical and allows users to access sites that are not directly below the drilling site. This drilling technique is commonly used to access oil, natural gas or coalbed methane reserves that are not located directly underneath a wellbore. Directional drilling can also be used to gather information about geological formations, construct relief wells, and install natural gas and electric utility lines where it is too difficult to excavate.
Directional drilling is a broad term that encompasses horizontal drilling, and several other drilling directions that radiate outward from a traditional vertical well. An example of these deviations can be seen in the image to the left. The use of directional drilling has grown, in part, because it allows drillers to create multiple wells from one vertical wellbore, which can decrease the cost and minimize the environmental impact of drilling operations.
The technology behind directional drilling has been around since 1891. According to the U.S. Environmental Protection Agency, this technology was initially implemented in Texon, Texas in 1929, with the first "truly horizontal well."
Although directional drilling has been used in the United States for over 85 years, the expansion of its use has been driven by technological improvements. he control that drillers have over the angle of wells has been one improvement. Technology now allows the angle of the drillbit, and thus the angle of the well, to be controlled in real-time, leading to increased efficiency, lower costs and improved accuracy. Additionally, computers have allowed drillers to create 3D maps of the area in which drilling will occur. These technological improvements have led to an increase in horizontal drilling, especially as technological improvements have led to an increased use of hydraulic fracturing to access oil and natural gas.
- U.S. Environmental Protection Agency, Directional drilling technology
- Society of Petroleum Engineers, Directional drilling
- U.S. Energy Information Administration, “Glossary, D” accessed January 24, 2014
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- Geology.com, "Directional and Horizontal Drilling in Oil and Gas Wells," March 4, 2015
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- U.S. Environmental Protection Agency, "Directional Drilling Technology," accessed March 4, 2015
- Society of Petroleum Engineers, "Directional drilling," February 2, 2015