Logging-While-Drilling
Operator
and logging contractor: LDEO-BRG
Hole: 2A (proposed site KGGH03-A)
Expedition:
NGHP-1
Location:
Krishna-Godavari Basin,
Eastern India (Bay of Bengal)
Latitude: 15° 52.119' N
Longitude: 81° 49.358' E
Logging
date: May 20-21, 2006
Sea
floor depth (drillers'):
1069 mbrf
Sea
floor depth (loggers'):
1066 mbrf
Total
penetration: 1119 mbrf
(50 mbsf)
The
logs were recorded using the LWD (Logging-While-Drilling) system, which allows
the acquisition of open-hole logs using instruments that are part of the drill
string itself. The advantages of this technique include being able to log in
formations that would not provide a stable hole for wireline logging (e.g. the
upper section of sedimentary formations) and logging a hole immediately after
it is drilled, so that it is in good condition and largely free of wash-outs.
The
following LWD tools were deployed in Hole 2A:
EcoScope (phase and attenuation
resistivity, density, porosity, geochemistry, gamma ray, temperature and
pressure)
geoVision
(resistivity-at-the-bit and gamma ray)
sonicVision
(velocity)
TeleScope
(drilling parameters)
After
tagging the sea floor, Hole 2A was spudded. To ensure that the LWD tools were
powered up to measure real-time data for gas monitoring, it was decided to
first drill with a relatively high pumping rate (350-400 gpm). The first 10 m of the hole were drilled
with a rotation rate of 10 rpm and a ROP of 25 m/h; the rotation rate was then
increased to 30 rpm while keeping all the other parameters unchanged down to 40
mbsf, and finally to 60 rpm, keeping the ROP around 25 m/h. After this testing
was concluded at about 50 mbsf, the tool string was pulled out of the hole and
the ship was moved by about 3 m to Hole 2B.
For further
questions about this hole, please contact:
Cristina Broglia
Phone:
845-365-8343
Fax:
845-365-3182
E-mail:
Cristina Broglia