Schlumberger’s expertise in advanced drilling technologies again bore fruit in a recent well drilled offshore Qatar, as engineers set ten new records in extend-reach operations as a Schlumberger team spent more than a year assigned to the project.
Among the landmarks was a new record for total depth of an astounding 40,320 feet for the well drilled by Schlumberger customer Maersk Oil Qatar in the Al Shaheen offshore field. Total stepout distance was 35,770 feet.
In all, the well set 10 records including:
• Longest well ever drilled
• Longest along-hole departure (37, 956 ft)
• Longest 8 1/2-in. section (35, 449 ft)
• Highest ERD ratio (AHD/TVD): 10.485
• Highest Directional Drilling Difficulty Index (DDI): 8.279
• Deepest directional control
• Deepest downlink, MWD transmission and LWD Geosteering (40,320 ft)
• Deepest battery-less operation
• Longest reservoir contact (35,449 ft)
• Longest open hole
“Extended reach drilling is a natural application of our high-performance drilling technology,” said Mike Williams, global sales manager, drilling and measurements, Schlumberger. “This helps our customers access more reservoir volumes from a single drill site, reducing overall costs and environmental impact.”
Drilled in two runs
The 8 1/2-inch horizontal section was drilled in two runs with the PowerDrive X5 and PowerDrive Xceed RSS. The TeleScope high-speed telemetry-while-drilling system transmitted geosteering information in real time and continuous measurements of the parameters that affect drilling efficiency.
The system also ensured that commands were received by the bottomhole assembly all the way to total depth. Continuous trajectory control enabled drillers to keep the wellbore within the 3-foot ‘sweet spot’ of the 10-foot thick reservoir 95 percent of the time, Schlumberger said.
One new technique involved using a turbine generator driven by drilling fluid circulation, allowing battery-less operation of the TeleScope, geoVISION and adnVISION systems.
Schlumberger provided close support as the project was designed and completed. Drilling engineers located in Maers’’s offices provided close collaboration and Operation Support Center (OSC) engineers made sure that clear communications and vital data were available for decision-making. Schlumberger’s repair and maintenance personnel prepared and tested the equipment as Maersk sent the drill to its unprecedented destination.
