DCBIL Tool Factsheet
Company: Wintershall Noordzee B.V.
Well:
F16-A05
• Scans borehole wall using ultrasonic waves
transmitted and received from a rotating transducer
located inside a Teflon sleeve.
• Travel time (provides borehole shape) and
attenuation (provides acoustic impedance) data
recorded.
• Three different size transducers are available,
optimised for 4.5-7”, 7–12” and >12”.
• Variable transmitter power levels and low
frequency level (250 kHz).
Fluid cell to calibrate
measurements in
real time
Limitations
• Borehole rugosity, ovalisation or
tool eccentering degrades images.
Heavy muds, or abundance of
solids in mud, cause signal
attenuation.
• Needs good acoustic impedance
contrast; generally performs better
in lithologies which are more
consolidated and have good
porosity contrast.
• Teflon mud-excluder can be added to improve
measurements in heavy muds.
• Measurement compensated downhole by
automatic gain control.
Common image artifacts
• Fluid cell measures borehole
fluid properties in real time for
measured data calibration.
• Centralisers on tool mandrel ensure correct
positioning of tool in borehole.
• Four, oriented, acoustic caliper curves can be
derived from travel time data.
• Can be combined with HEXDIP dipmeter or form
part of STAR imager.
Length
14.9 ft [4.55 m]
Weight
270 lb [122.5 kg]
Diameter
3.63 in [92.1 mm]
Hole size
4.5–18.0 in [114 – 457mm]
Max. deviation
90°
Temperature
400°F [204°C] max.
Pressure
20,000 psi [138 MPa] max.
Resolution
Key applications
Image coverage 100% of borehole
6 rev/s (11 rev/s on STAR)
• Eccentering and ovalisation cause
vertical banding in images; hole
spiral marks may also affect
images.
• Vertical stripes (tool marks)
dominate over intervals with soft
rocks or thick mudcake.
• Tool grooves show up in deviated
holes.
• 1.44° [250 samples/rev]
azimuthally.
• Up to 0.2” vertical sampling rate.
• Resolves features down to
approx. 1” [3 cm].
Operational specifications
Scan rate
Teflon sleeve covers
rotating transducer
Pressure
equalisation
chamber for
transducer unit
Logging speed 600 ft/hr [182 m/hr] @ 60
spf
Figure 1
• Accurate borehole shape
determination
• Fracture detection.
• Structural studies.
• Borehole stress
• Fracture and fault orientation.
• Borehole imaging in oil-based
muds.
• Limited sedimentological
applications.
Structural dip analysis
Company: Wintershall Noordzee B.V.
Well:
F16-A05
N
Dip Azimuth Vector Plot
Top of interval
(5665 m)
Dip-azimuth trend
5827 m
Top Lower Slochteren
Top Westphalian ?
Bottom of interval
(6244 m)
Dip-azimuth vector plot of all mudstone planes, Interval 5565-6244m.
The overall trend throughout the logged section is a NW dip-azimuth
with a change to a more NNW-ly trend above 5827m MD.
Note, this diagram type shows only azimuth of bedding planes and not the dip
amount. Diagram is read from bottom to top of logged section.
Figure 2
Structural dip analysis
Company: Wintershall Noordzee B.V.
Well:
F16-A05
All bedding features and mean bed values,
Entire section 5660-6245 m.
Figure 3
Structural dip analysis
Company: Wintershall Noordzee B.V.
Well:
F16-A05
Mean bed values
entire logged section, 5665-6244 m
Silverpit
L.Slochteren
?
Westphalian
Mean dip is 5-9 deg. towards NW thoughout the Westphalian, Lower
Slochteren and most of the Silverpit sections. An change to 14 deg. towards
NNW is seen in the topmost part of the Silverpit, indicating a minor angular
unconformity at 5827 m. Another possible minor angular unconformity is
found at 6173 m.
Note the restricted dip scale: 0-50 deg.
Wulff plot, upper hemisphere.
Figure 4