I N NOVATI N G WH I LE DR I LLI N G
reservoir understanding, and enabled
the operator to make informed decisions
for maximizing the NTG ratio for each
well, thus improving the productivity of
the wells. By providing higher-resolution
mapping, the service revealed the internal
layering and quality variation within the
reservoir, optimizing the well path and
production. The PowerDrive Archer high build rate
RSS enabled the operator to effectively
steer the horizontal section of the wells to
handle the abrupt structure changes and
target multiple sand bodies in one well.
The operator used the multilayer map-
ping-while-drilling service in well A to
map the top of the target sand 2.1 m away
and the base of the target sand 5.2 m away
as soon as it came out of the casing shoe.
The service mapped the top and the base
of the sand body throughout the section,
clearly showing the pinchout of the sand
body. The well was drilled for 256 m inside
the sand body, with 50 m/hr average ROP
while achieving 100% NTG.
Well B was drilled in an area lack-
ing control wells, causing uncertainties
about the thickness and dip of the reser-
voir structure. At 2,960-m MD, the service
mapped the abrupt upward dip change of
the base of the current sand body, enabling
the operator to build inclination of the well
path and avoid drilling out of the current
good-quality sand. At 3,030-m MD, the ser-
vice mapped the top of the sand body and
a poor-quality layer at the upper part of the
The multilayer mapping-while-drilling service mapped the top and the base of a
sand body in China, clearly showing the pinchout. The well was drilled for 256 m
inside the sand body, with 50 m/hr average ROP while achieving 100% NTG.
reservoir. The geosteering team dropped
the inclination and avoided drilling into
the poor-quality zone at the top. At 3,123-m
MD, the service inversion showed that the
formation dip changed from 0.5° down-
ward to 8.5° upward. The operator called
for total depth (TD) based on this informa-
tion. For this well, the team achieved a
91.5% NTG ratio, drilling 215 m in sand for
the total horizontal section of 235 m.
Conclusion The ability to double the depth of detec-
tion range compared with previous bed
boundary detection services has helped
operators deliver clearer boundary delin-
eation, enabling more precise real-time
steering and faster turnaround time. By
landing the well more precisely, operators
can avoid drilling out to nonproductive
sand and reduce costs and risks associ-
ated with drilling in complex formations.
Since deployment, the multilayer map-
ping-while-drilling service has drilled and
steered more than 700,000 ft in over 200
runs and 10,000 operating hours. In addi-
tion to Australia and China, it has helped
operators in the United States, South
America and the Middle East place the
well in the best part of the reservoir, lead-
ing to improved production, reduced cost
and risk, and consistent performance. DC
PeriScope Edge,
ShortPulse, PowerDrive
Orbit and PowerDrive Archer are marks of
Schlumberger. The service mapped the abrupt upward dip change of the base of the current sand body, enabling the operator to build
inclination of the well path and avoid drilling out of the current good-quality sand.
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