Well Control Procedure for Non-Shearable String

There are many cases when non-shearable string is across the BOP therefore blind shear rams will not be able to shear the string to secure the well if needed. The special procedure must be in place to deal with this situation. This is an example of well control procedure for non-shearable string. If you want to use it for your rig, it must be modified to match with your rig operation.

Well Control Procedure for Non-Shearable String FB

  • Define which equipment is unable to be sheared such as BHA, thick wall drill collar, testing tool, downhole pump, etc. This step should be done ahead of the time.
  • Perform pre-job safety meeting with personnel involved in operation.
  • Before pulling out non-shearable string through BOP, flow check must be conducted to ensure a well condition.
  • Driller must ensure well static before pulling out.
  • Driller must ensure all line up for shut line is correct.
  • Shut in criteria if the well control indicator is seen.
    • If the risk is acceptable, pull the string out of the hole and shut the well in using blind or blind/shear rams. If this method is not applicable, another option is to make up a shearable string as drill pipe and run in hole. Then shut the well in using annular preventor or rams preventor.
    • If the risk is not acceptable, stab full opening safety valve and shut the well in via annular preventor. It might be possible to close rams if size of rams match with the non-shearable string. Driller must ensure the correct space out to prevent closing the BOP (annular or rams) on non-slick surface.

These procedures will be followed if the well is unable to be secured from the steps above.

Drop Drillstring During Tripping Operation

  • Lower the string close to the rotary table
  • Close Annular Preventer
  • Tie a rope on the elevator latch
  • Lower the block and takes the weight off the elevator.
  • Pull the rope to unlatch the elevator
  • Open Annular Preventer to drop the string
  • Shut the well in via blind/blind-shear rams

Drop Drillstring If The String Is Made Up To Top Drive

  • Lower the string close to the rotary table
  • Set slips and break the connection at top drive for one turn
  • Pick up and remove slips
  • Close Annular Preventer
  • Break out the top connection as fast as you can until the string is sceptered from top drive.
  • Open Annular Preventer to drop the string
  • Shut the well in via blind/blind-shear rams

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