After the seismic level had been acquired at a connection, windowed
real-time waveforms were transmitted uphole using mud pulse telemetry. The
checkshots were then processed from the waveforms at the wellsite, and
real-time depth updates were calculated while drilling continued. A real-time
corridor stack processed from the real-time waveforms showed the seismic
position. Extrapolating a depth projection to the formation top from the
look-ahead (reflectivity) information enabled the drilling team to geostop the
12 1⁄4-in section before it penetrated the carbonate formation.
Set casing without penetrating formation top
Using seismicVISION service to revise the depth prediction in real time
at every connection, the drilling team resolved the ±50-m uncertainty
about the depth of the carbonate reservoir and geostopped the 12 1⁄4-in
section before it penetrated the formation top. The 9 5⁄8-in casing was
set within 20 m of the formation top, as was required for successful completion
of the well.