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Oil, Gas & Mining vocabulary · Drilling & Wells

Drill string

Meaning in oil, gas & mining, with examples

nounCommon term

In oil, gas & mining, drill string means: The long column of connected drill pipe, heavy collars and tools that runs from the rig down to the bit, turning it and carrying drilling mud to the bottom of the hole.

In Turkish: sondaj dizisi, tij dizisi, dizi

How it is used

Rig crews say 'the string' for short. The lower part with the bit, drill collars and tools is the bottom hole assembly (BHA). Common problems are stuck pipe and twist-offs. The string is tripped in and out of the hole one stand at a time.

Example sentences

  1. The drill string got stuck at 2,650 metres after a shale section collapsed.

  2. We pulled the drill string to change the bottom hole assembly.

Common collocations

  • drill pipe
  • bottom hole assembly (BHA)
  • stuck pipe
  • drill collars
  • drill bitThe cutting tool at the bottom of the drill string that breaks and crushes rock as it turns, making the hole deeper.
  • tripTo pull the drill string out of the well or run it back in, for example to change a worn bit or a tool. The whole operation is called a trip.
  • drilling rigThe complete set of machinery used to drill a well, including the tower, engines, pumps, hoisting system and the equipment that turns the drill pipe.
  • derrickThe tall steel tower on a drilling rig that holds the hoisting equipment used to raise and lower the drill string and casing.

More terms: Drilling & Wells

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