MPD Managed Pressure Drilling GF Landsbyen 2007

Outline What is MPD Why MPD Conventional drilling vs MPD

Large Drilling Window Conventional Drilling Bottom Hole Circulating Pressure Time Pore Pressure Fracture Pressure

Small Drilling Window (Losses) Conventional Drilling Bottom Hole Circulating Pressure Time Fracture Pressure Pore Pressure

Small Drilling Window (Kick) Conventional Drilling Bottom Hole Circulating Pressure Time Pore Pressure Fracture Pressure

Why not conventional drilling? Small drilling window Conventional drilling is not possible without the risk for kick or severe losses Improved well productivity and increased net present value? Max pore pressure gradient Min frac pressure gradient

MPD Can drill with BHP ± 2,5 bar (requires automatic choke) – Experience from UBO project: ±5 bar Normal annulus friction for drilling at 1900 m is app 0,08 sg or 15 bar. Max pore pressure gradient Min frac pressure gradient THIS IS POSSIBLE WITH MPD MPD can be the solution when small overbalance is an advantage

Conventional drilling Open system Kick detection by: – Increased volume or flow – Connection gas Close BOP Circulate out influx w/ low flowrate Gas via poor boy degasser (vent) No separation of liquids Circulate kill fluid w/ low flowrate Continue drilling if possible

MPD Closed system Improved kick detection by: – Accurate volume, flow and pressure measurements – Background gas Rotating Control Head closed Circulate out influx Continue drilling with increased BHP Rig well control equipment is still available