NON-STOP
DRILLER

Murphy Malaysia Kikeh Spar

[14 wells, 28 sections]

Client identified problems with depleted reservoir zones resulting in drilling fluid losses. Relatively unconsolidated and poorly sorted sands present in the field geology. Drilling window narrow due to pore pressure/fracture pressure gradient uncertainties. Client predicted borehole instability, differential sticking, high background gas probability. Managed Pressure Drilling with Continuous Circulation System used to drill with lighter muds (WBM and OBM) and control the ECD/BHP accurately within the drilling window to avoid losses and NPT. Compact footprint of equipment meant this was easily achievable in a limited space environment offshore.

Results:

• Minimised Drilling problems with NSD continuous circulation and MPD ASBP.
• Prevented stuck pipe by allowing uninterrupted transport of cuttings.
• Minimize BHP surging on stop start circulation due to gel strength.
• Reduced ECD variations in narrow formation pressure margin wells.
• Prevented Wellbore Ballooning and wellbore instability by maintaining CBHP.
• Zero well control incidents or significant mud losses occurred during drilling or MPC.
• No differential sticking in depleted sands or stuck pipe occurred during drilling.
• Able to determine the drilling boundaries with dynamic FITs / LOTs.
• NSD assist in hole cleaning of high angle wellbores by keeping cuttings in suspension.
• Prevent settling of cuttings on the low side of the hole.
• Prevent sliding of cuttings at hole angles < 45deg.

OilSearch PNG

[22 wells, 22 Sections]

Client observed multiple lost BHA’s whilst drilling surface and intermediate sections leading to multiple side tracks. Losses observed up to and including total losses. Foam drilling technologies were identified and utilized however time spent adding surfactants and breaking down the foam before making a connection added 2-3 days to drilling each section. Heli-rig operating in the PNG Highlands so equipment footprint and personnel numbers required to be small and light. Continuous Circulation system was used to eliminate stuck pipe and lost BHA’s through maintaining foam drilling over each connection.

Results:

• Minimised Drilling problems with NSD continuous circulation and eliminated NPT related to breaking down foam over each connection.
• Eliminated lost BHA’s in top-hole sections and prevented stuck pipe by allowing uninterrupted transport of cuttings with total losses.
• Small NSD Crew of 2 people to rig up run and maintain the system in a remote location.
• Heli portable NSD equipment footprint easily transportable between rig sites.
• Maintained strict zero discharge environmental policy for PNG.