Acquire borehole seismic measurements for real-time, time-depth-velocity information without disrupting drilling operations.
Real-time seismic waveforms guide key exploration drilling decisions in East Asia
SLB set casing within 20 m of top of key formation in offshore exploration well despite uncertainty about formation depth.
We used seismicVISION™ seismic-while-drilling service for casing point selection. We geostopped wellbore within 10 m of key formation top at a TVD of approximately 3,000 m and avoided time and expense of contingency strings.
Select casing point
An operator drilling an offshore exploration well in East Asia expected to encounter a key formation at about 3,000 m TVD. Because the formation was suspected of being overpressured, the operators objective was to set casing within 20 m of its top. That objective would have been difficult to achieve using conventional 2D surface seismic, which had a depth uncertainty of ±100 m.
Acquire seismic data while drilling
The seismicVISION seismic-while-drilling service provided checkshots that enabled drilling to be geostopped within 10 m of the formation top. Checkshots were acquired at planned levels during the acoustically quiet periods while connections were made. A standard three-air-gun cluster deployed at surface was used as a source. As the wellbore neared the formation top, checkshots also were acquired at mid-stand levels.


The checkshots were processed from windowed real-time waveforms transmitted uphole by mud pulse telemetry, and real-time depth updates were calculated while drilling. A real-time corridor stack processed from the waveforms showed seismic position, and geostopping decisions were guided by depth projections to the key formation, which were extrapolated from look-ahead (reflectivity) information.
Save time and expense
Use of the seismicVISION service enabled the operator to geostop the wellbore less than 10 m from the top of the overpressured formation. This accurate casing point selection allowed successful construction of the well to TDwithout the time and expense of contingency strings.
