FI (list display)

  • E21B15/00
  • Supports for the drilling machine, e.g. derricks or masts [1,7] HB CC 2D129
  • E21B15/02
  • .specially adapted for underwater drilling (E21B 15/04 takes precedence) [2006.01] HB CC 2D129
  • E21B15/04
  • .specially adapted for directional drilling, e.g. slant hole rigs [3] HB CC 2D129
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