(n) (1) steel pipe placed in an oil or gas well to prevent the wall of the hole from caving in, to prevent movement of fluids from one formation to another and to aid in well control
US Department of Labor, Occupational Safety & Health Administration (OSHA), Oil and Gas Well Drilling and Servicing eTool, Washington, DC. This is an abridged version of the Dictionary of Petroleum Terms provided by Petex and the University of Texas Austin, USA 2001. http://www.osha.gov/SLTC/etools/oilandgas/glossary _of_terms/glossary_of_terms_a.html, (Oil Well Drilling Sci and Tech - Amer) {492}