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CASE HISTORY
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LongBow Milling System Completed Casing Exit in One Trip,
Saved USD 140,000
Location: Celle, Germany
anchor. Both watermelon mills were dressed
with Glyphaloy™ AMT cutters to enhance
milling operations.
LongBow milling system
dressed with AMT
A customer in Celle, Germany needed to
cut a window in 133∕8-in. 68 lb/ft casing. To
create the appropriate window profile, we
recommended the Baker Hughes extra-long
WindowMaster G2™ XL whipstock assembly
and the LongBow™ milling system dressed
with advanced milling technology (AMT)
carbide. The LongBow system features wider
spacing between the window and watermelon
mills to create longer, wider profiles. Before
setting the whipstock, we performed a
cleanout to remove any debris from the
casing wall so the bottom trip anchor could
be securely set.
We began the job by tripping in hole with
a bottom hole assembly (BHA) comprised
of a WindowMaster G2 XL whipstock, a
PathMAKER™ mill, and LongBow lower and
upper watermelon mills, all connected to
a mechanical bottom-trip TorqueMaster™
The BHA was tripped in slowly at two minutes
per stand until we reached 648 m (2,126 ft).
The Baker Hughes GyroTrak™ measurement
while drilling (MWD) system was used to
orient the whipstock to 302 degrees. We
topped off the bridge plug, set the bottom
trip anchor, picked up, and took overpull to
confirm the anchor was set.
The string was lowered and we set down
enough weight to shear the anchor bolt.
With the WindowMaster G2 XL and LongBow
systems in place, we began the casing exit
operation and milled 8.9 m (29.15 ft) in
10.5 hours. We also drilled an additional
12.2 m (40 ft) of rathole in only four hours.
No anomalies were observed and the mills
passed through the window with minimal
tortuosity, after which we performed an
additional cleanout run to dislodge a
formation blockage. When the operation was
complete, we pulled out of hole with minimal
wear on the mills, indicating that the milled
window was clean and at proper gauge.
The PathMAKER mill measured 5∕8-in. under
gauge, and the lower watermelon and upper
watermelon mills measured only 1∕32-in. and
3
∕32-in. under gauge respectively. A total of
21.1 m (69.15 ft) were drilled in a single-trip
that took only 14.5 hours.
Results
nnMilled
a clean window and
drilled a rathole in a single trip,
taking only 14.5 hours to
complete the operation
nnIncreased
milling rates with
AMT carbide
nnSaved
operator 24 hours of
rig time and an estimated
USD 140,000
nnLowered
NPT
Challenges
nn133∕8-in.
nnSea
68lb/ft L-80 casing
water
nnOperator
needed to run
full gauge bit and bent motor
through window
Baker Hughes solution
nnDeployed WindowMaster
G2
XL whipstock assembly with a
LongBow milling system and
a PathMAKER mill
nnMilled
8.9 m in 10.5 hours
nnDrilled
an additional 12.2 m of
rathole in only four hours
nnPumped
cement, set the anchor,
and cemented the whipstock
CASE HISTORY
The combination of the LongBow milling
assembly and AMT cutting technology
saved the operator 24 hours in rig time
and an estimated USD 140,000. The job
was successfully completed and left the
customer with the ability to complete drilling
operations without any visible tortuosity in
the window area.
Mill
Post-Operation OD
121∕4-in. OD PathMAKER
115∕8 in.
5
11 ∕32-in. Lower LongBow Watermelon
11 ∕32 in.
1
121∕4-in. Upper LongBow Watermelon
125∕32 in.
3
31
30
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© 2014 Baker Hughes Incorporated. All rights reserved. 39945 02/2014
Mill Wear
∕8 in.
∕32 in.
∕32 in.