Slant Drilling in Michigan: Diffusion of a Critical Resource Extraction Technology. Robert V. Brady, Ferris State University, Big Rapids, MI 49307 Slant drilling, also called directional drilling has been an important technology used in the Petroleum Industry in Michigan for decades. Initially, as everywhere, wells drilled for oil and gas in Michigan were drilled vertically. If they deviated from vertical it was an unintended consequence of local geological conditions, such as subsurface faults. Eventually, it became apparent that valuable oil and gas targets were also present at locations that could not be reached by drilling a simple vertical (or straight) well. Sometimes, potential oil and gas reservoirs were thought to be located beneath cultural features, such as schools, businesses, or residential neighborhoods. Similarly, it was speculated that some reservoirs were present beneath natural features such as wetlands, rivers, and lakes. In other instances it was suspected that known reservoirs extended beneath various cultural and/or natural features. Slant drilling provided an opportunity to gain access to many of these inconveniently located possibly productive zones. In still other cases, especially during the heyday of the Niagaran reef play from the late 1960s to the early 1980s, proximity indicators encountered on vertically drilled holes could justify slant drilling to find the suspected nearby reservoirs. Finally, sine the 1980s a variation on slant drilling, called horizontal drilling, has enabled substantially greater recovery from a number of reservoirs around the State.
