Most gas shales are found in extensive seams hundreds or thousands of meters beneath the surface. These seams can be accessed through conventional vertical drilling, but the most productive method is usually horizontal drilling. In this technique a well is begun in the traditional way, with the auguring of a pilot hole usually some 6 to 15 meters (20 to 50 feet) deep. This is lined with a steel pipe some 40 to 50 cm (16 to 20 inches) in diameter, called the conductor casing, that is cemented into place. From there the borehole is drilled straight down, passing through numerous rock layers that may include contaminable freshwater aquifers used for private wells or municipal water supply. This portion of the borehole is Подплатена с циментирана стоманена тръба, наречена повърхностна корпуса . в зависимост от производствените нужди или екологични разпоредби, друга тръба, наречена междинна корпуса, може да бъде циментирана вътре в повърхностния корпус .
At a predetermined "kickoff point" (in some cases above the shale formation, in other cases within it), a steerable drill bit is installed, and the borehole is turned to the horizontal. From there drilling continues within the shale, sometimes for another thousand meters or more. When this lateral section of the well is drilled, the entire borehole is lined with yet another pipe called the production корпусът . В много операции повече от един кладенец може да бъде пробит от единична повърхност (или "подложка") или повече от една странична секция може да излъчва от един сондаж .
