Cement is then pumped into the space between the outside of the casing and the formation. Once it is set, this cement prevents the flow of fluid from the formation and holds the casing in place. After the cement sets, the drilling company may extend the well by drilling out the bottom of the casing with a smaller bit. The diameter of the drill bit may progress from 36 in. Each section of well varies in length from several hundred feet to in excess of 10,000 ft, and may take anywhere from a few hours to weeks to complete.
Little information is gleaned during the drilling process.
Some data can be derived from measuring the energy required to drill each foot of the well, or by monitoring rock debris or drilling mud pumped from the well. Comprehensive information about the formation is obtained only by lowering electronic instruments into the well. This process, called wireline logging, requires the expertise provided by Baker Atlas. About Baker Atlas 2001 Baker Hughes Incorporated. All Rights Reserved.