Weiland J.,SPE Annual Technical Conference and Exhibition |
Cuttitta M.,SPE Annual Technical Conference and Exhibition |
Soto G.,SPE Annual Technical Conference and Exhibition |
Wandstrat M.,SPE Annual Technical Conference and Exhibition |
Jebutu S.,SPE Annual Technical Conference and Exhibition
JPT, Journal of Petroleum Technology | Year: 2011
The combination of seismic models with real-time logging-while-drilling (LWD) measurements led to the reduction in the geologic uncertainty in Mars Well A-8. The LWD density tool used two receivers, such that the borehole-fluid and near-wellbore influence could be compensated for and the formation influence determined. Measurement resolution was the 8-in. distance between the two receivers, while the depth of investigation was less than 3 in. Surface-seismic data are assigned subsea-true-vertical-depth (TVD) values during processing. TVD includes the distance between the permanent datum (mean sea level) and drill-depth zero, which was the rig floor. The mechanical risks of the well could be balanced with the directional needs to yield an optimum borehole. A rotary-closed loop-system (RCLS) steering mechanism enabled directional control throughout the well path. The RCLS enabled continuous steering capabilities to minimize wellbore tortuosity.