Drilling Pipe - PetroFact #7

#7 

Drill Pipe 

What is the standard length of drill pipe?

For deep wells, which tests are used for drill pipe after they finished a well? 

How do they classify a drill pipe? 

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Drill pipe is hollow, thin-walled, steel or aluminum alloy piping that is used on drilling rigs. It is hollow to allow drilling fluid to be pumped down the hole through the bit and back up the annulus. It comes in a variety of sizes, strengths, and wall thicknesses, but is typically 27 to 32 feet in length (Range 2). Longer lengths, up to 45 feet, exist (Range 3).

For deep wells, this requires tempered steel tubes that are expensive, and owners spend considerable efforts to reuse them after finishing a well. A used drill stem is inspected on site, or off location. Ultrasonic testing and modified instruments similar to the spherometer are used at inspection sites to identify defects from metal fatigue, in order to preclude fracture of the drill stem during future well-boring. 

Drill pipe is classed as new (N class), becoming premium (P-class) and finally down to C (C 1 to 3) as fatigue is accumulated and as the outside diameter is worn down by usage. Eventually, the drill pipe will be graded as scrap and marked with a red band.