Develop thin oil-bearing sands to mitigate field production
The Cuu Long Joint Operating Company (CLJOC)—a joint venture of
PetroVietnam, Perenco, the Korea National Oil Corporation (KNOC), SK Energy,
and Geopetrol—was experiencing a decline in oil production from 25 wells
in the Cuu Long Prospect oil field offshore southern Vietnam. Production in the
field had begun in 2003 from a fractured granite basement and later reservoirs
were developed in the overlying sands.
During exploration and development drilling, CLJOC identified additional
thin oil-bearing sands in nearby reservoirs and decided to develop them to
reverse the decline in field production. Achieving that goal would require long
laterals and precise well placement to maximize reservoir exposure.
Use distance-to-boundary measurements to geosteer RSS
The PeriScope bed boundary mapping service provided distance-to-boundary
data with azimuthal gamma ray and average resistivity measurements. The
PowerDrive X6 RSS allowed continuous rotation of the drillstring while steering
the well, which optimized drilling efficiency, maximized ROP, and minimized the
time spent on dedicated hole-cleaning trips.
While drilling the first lateral, the PeriScope service detected a
conductive boundary below the well path, which enabled proactive geosteering
decisions to build the trajectory and avoid a premature exit into the
underlying shale. The 129-m lateral was placed within the target sand,
exceeding the initial objective of 100 m. The well is producing more than 1,600
bbl/d of oil— 50% more than the expected rate—with near-zero water