Oil Search well ADD-5 on Papua New Guinea, August 2009
  • Foam drilled 17 ½” section 200m to 1500m
  • Injected foam fluid - 2000 scfm air, 32gpm water, 1% foaming agent, 2 lb/bbl Barazan D
  • Maximum standpipe pressure of 1600 psi
  • Maintained constant circulation over whole section, 28 drill pipe connections

Challenging environment for testing the NSD system because: 
  • The NSD valves were in the open hole
  • Hole angle 20 degrees inclination
  • Extreme vibration due to shallow drilling depth
  • Seal off against 1600psi compressed air pressure
  • Drilled solids contaminated environment, with cuttings not suspended in lubricating and viscous mud
The NSD system allowed Oil Search to accomplish the following: 
  • Drilling with stands, compared to drilling in doubles conventionally due to need to make connections one single off bottom. 
  • Reduced connection time from 35-45 mins to only 10-15 mins, by eliminating need to depressurise the drillpipe, and re-establish stable foam circulating conditions after each connection. 
  • Elimination of high injection pressure spikes up to 2500psi, experienced during conventional foam drilling connections. 
  • Substantial risk reduction of stuck pipe during connections, due to drilled solids drop out, or formation collapse due to cyclic pressure variations in the wellbore.  
  • No stuck pipe incidents.
  • Allowed section to be drilled to planned TD. On conventional foam and air drilling jobs, circulation can not be re-established after a connection beyond a certain depth.