Pressure while Drilling Data Improves Reservoir Drilling Performance

Abstract A new down-hole annular Pressure-While-Drilling (PWD) tool has recently been applied to assist drilling of the reservoir section on the Statfjord Field, offshore Norway. In these highangle wells it is critical for drilling success to maintain the mud weight and Equivalent Circulating Density (ECD) within safe operating limits defined by the formation fluid, collapse, and fracture pressures. Operating outside these limits has historically led to expensive lost circulation, differential sticking, and pack-off incidents. Monitoring the actual down-hole pressure in real-time with a PWD tool, rather than relying on inferred pressures from predictive models, has allowed the Operator to stay within and better define these operating limits. The Operator used this improved hydraulics information to avoid pressure-related hole problems, optimise drilling practices, test hydraulics models, and obtain a greater understanding of the formation pressure limits.