![]() ![]() Utility line: Utility service lines such as those delivering electricity, water, or natural gas are sometimes installed by directional drilling. (F) Installation of underground utilities When combined with hydraulic fracturing, horizontal drilling can convert unproductive shales into fantastic reservoir rocks. However, if the well is turned and drilled horizontally through the rock unit for five thousand feet, then that single well will have a pay zone that is five thousand feet long - this will usually result in a significant productivity increase for the well. If a rock unit is fifty feet thick, a vertical well drilled through it would have a pay zone that is fifty feet in length. Some horizontal wells have over one mile of pay zone penetration.Ĭ) Increase the length of the "pay zone" within the target rock unit. Maximize pay zone: If a vertical well is drilled through a 50-foot-thick reservoir rock, then natural gas or oil can seep into the well through 50 linear feet of "pay zone." However, if the well is turned to horizontal (or the same inclination as the rock unit) and drilled within that rock unit, then the distance of penetration within the pay zone can be much greater. ![]() (C) Increase the length of the "pay zone" This method significantly reduced the footprint of natural gas development within the campus area. Wells are expected to produce a total of 110 billion cubic feet of gas. InĢ010, the University of Texas at Arlington was featured in the news for drilling 22 wells on a singleĭrill pad that will drain natural gas from 1100 acres beneath the campus. This method has been used to reduce the surface footprint of a drilling operation. The city or park and the well is drilled at an angle that will intersect the reservoir.ī) Drain a broad area from a single drilling pad. This reservoir might still be tapped if the drilling pad is located on the edge of Sometimes a reservoir is located under a city or a park where drilling is impossible orįorbidden. They are graphically illustrated by the six drawings on this page.Ī) Hit targets that cannot be reached by vertical drilling. Why Drill Wells That Are Non-Vertical?ĭirectional and horizontal drilling have been used to reach targets beneath adjacent lands, reduce the footprint of gas field development, increase the length of the "pay zone" in a well, deliberately intersect fractures, construct relief wells, and install utility service beneath lands where excavation is impossible or extremely expensive.īelow is a list of six reasons for drilling non-vertical wells. The alternative would be to drill many wells, each requiring a drilling pad, pond, access road and gathering line. Over a 25-year lifetime, the wells are expected to produce a total of 110 billion cubic feet of natural gas. These wells are draining the natural gas from about 1100 acres beneath the campus. In 2010 the University of Texas at Arlington drilled 22 wells on a single platform. This reduces the footprint of drilling operations. Minimize footprint: One drilling pad can be used to drill a number of wells. (B) Drain a large area from one drill pad Examples are the Marcellus Shale of the Appalachian Basin and the Bakken Formation of North Dakota. When directional drilling is combined with hydraulic fracturing, some rock units which were unproductive when drilled vertically can become fantastic producers of oil or natural gas. In these cases, an ability to accurately steer the well in directions and angles that depart from the vertical is a valuable ability. However, drilling at an angle other than vertical can obtain information, hit targets, and stimulate reservoirs in ways that cannot be achieved with a vertical well. Most wells drilled for water, oil, natural gas, information or other subsurface objectives are vertical wells - drilled straight down into the earth. However, a well could be drilled just outside of the populated area or park and then steered directionally to hit the target. For example, it may not be possible to get a drilling permit for a well located within a populated area or within a park. (A) Target can't be reached by vertical drillingĭirectional drilling under city: Directional drilling can be used to reach targets that cannot be drilled with a vertical well. ![]()
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