دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: drill pipe that is like conventional drill pipe except that it is manufactured with a thicker wall, which increases its weight and tensile strength. For example. five-inch lEU grade E75 standardweight drill pipe weighs 19.5 pounds per foot (29 kilograms per metre). while five- inch lEU grade E75 heavyweight drill pipe weighs 25.ro pounds per foot (38.4 kilograms per metre). Heavyweight drill pipe is placed in the top of the string to support a very long string of pipe. Heavyweight drill pipe may be used in the drill stem when high-tensile strength drill pipe is required hit high-grade steel cannot be used because of the highgrade steels susceptibility to hydrogen embrittlernent, which is a form of corrosion caused by hydrogen sulphide. Compare heavy- walled drill pipe.

n: thick -walled drill pipe used in directional drilling and placed between the drill collar and drill pipe.