I N NOVATI N G WH I LE DR I LLI N G
Multilayer mapping-while-drilling
service delivers real-time insights
to optimize reservoir exposure
Deployments in Australian CSG and offshore China
demonstrate service’s ability to provide precise
boundary, layer detection for better steering
BY VERA KRISSETIAWATI WIBOWO AND HAIFENG WANG, SCHLUMBERGER
To overcome structural complexity, poor
seismic coverage and technology limita-
tions that can lead to extended drilling
time, multiple runs or additional logging,
drillers require technology with capabili-
ties to map more than one boundary and
accurately estimate reserves in areas of
geological uncertainty. Conventional
boundary mapping-while-drilling technol-
ogy with a limited depth of investigation
has driven industry demand for technol-
ogy that improves reservoir identification,
enhances decision making while drilling
and helps drillers stay in the reservoir as
long as possible.
Drillers in Australia and offshore China
have doubled the depth of detection range
using the PeriScope Edge multilayer map-
ping-while-drilling service . The service
provides deep resistivity measurements,
higher resolution and a high-definition
inversion process, providing continuity,
definition and certainty that improves
accuracy of multilayer mapping while
drilling. Multilayer technology
The multilayer mapping-while-drilling
service combines advanced inversion
with measurements coming from axial,
tilted and transverse antenna, which pro-
vide faster and higher delineation of reser-
voir layers and formation evaluation while
drilling. The antennas measure resistivity
and anisotropy deep into the surround-
ing formation, providing high-resolution
measurements and enabling Rh and Rv
mapping of each formation layer, which
is supported by end-to-end workflows in
a digital environment to work out the
accurate multilayer mapping around the
wellbore while drilling. The technology
has six transmitters with four receivers
that operate at three frequencies, enabling
complete geosteering multilayer mapping
and formation evaluation.
By delivering real-time ultra-high reso-
lution, the service provides precise bound-
ary and layer detection for better steer-
ing direction in various reservoir types,
including complex thinly bedded and
compartmentalized reservoirs. Gamma
ray, propagation resistivity and deep direc-
tional resistivity measurements provide
accurate input for formation evaluation
while drilling, helping the operator place
the well in the best part of the reservoir
and extend reservoir exposure, ultimately
improving production. The service reveals
up to eight layers and provides mapping
beyond a 25-ft radius, delivering accu-
rate geosteering in reservoirs where mul-
tiple thin layers could not previously be
mapped. With remote capabilities, the service
promotes a digital collaboration for faster
decision making while navigating produc-
tion zones within complex reservoirs.
Case study: Australian operator
drills long dual-lateral wells
within very tight boundaries in
unmapped formation
Overview of the second dual-lateral well drilled with the multilayer mapping-while-
drilling service. The upper lateral set several onshore records for the operator as
the highest ERD-ratio well and the longest onshore lateral length from heel to toe
(2,300 m). It was also the longest lateral drilled in Bowen Basin, Australia.
As coal-seam gas (CSG) production con-
tinues to increase in Eastern Australia,
conventional CSG development methods
present multiple geosteering and drilling
challenges. A common concept for CSG
development includes drilling surface-to-
inseam (SIS) wells, but this process con-
sists of drilling horizontal multilaterals to
intercept a vertical well and often requires
multiple attempts. The horizontal laterals
stay in seam to maximize coal-seam expo-
sure. After drilling, water is pumped out of
the intercept well, causing gas to come out
after the pressure has been reduced. The
thin, 1–2-m seams create steering chal-
lenges, especially when drillers use low-
end reactive geosteering tools. Structural
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