IODP-MSP drilling and logging contractor: ESO and Weatherford Wireline Services
Hole: M0059B
Expedition: 347
Location:
Latitude: 55° 0.299' N
Longitude: 10° 6.508' E
Logging
date:
Sea floor depth (driller's): 36.7 m DRF
Sea
floor depth (logger's): 36.7 m WRF
Total
core recovered:
28.63 m (56.511 % of cored section)
Lithologies:
The logging data was
recorded by Weatherford Wireline Services under supervision by personnel of RWTH Aachen University, Institute for Applied Geophysics and Geothermal Energy, which is part of the European Petrophysics Consortium
(EPC). Data were
provided by EPC to Lamont-Doherty Earth Observatoy, which formatted the files for inclusion in the online log database.
|
Tool string |
Run
|
Top depth (m WMSF)
|
Bottom depth (m WMSF)
|
Pipe depth (m WSF)
|
Notes |
|
1. MAI/MCG
|
|
|
|
20 |
|
|
2. MAI/MCG
|
2 |
0 |
186.6 |
87 |
|
3. MSS/SGS/MCG |
3 |
0 |
73.9 |
20 |
|
Hole M0059B was drilled with a 8 1/2 inch bit. In preparation for logging, the hole was circulated with sea water and the drill string was pulled back to 20 m WSF. The first tool string (MAI/MCG), Array Induction and Gamma Ray, reached 72.5 m WSF, where the uplog started. The drill pipe was then run again to 204 m WSF and set at 87 m WSF; the MAI/MCG reached 196.6 m WSF and acquired an uplog from this depth.While pulling out of the hole, an overpull was observed. thus a decision was made to set the pipe again at 20 m WSF and deploy a MSS/SGS/MCG tool string (Sonic/Spectral Gamma Ray/Gamma Ray); data were collected from 72.5 m uplog.
The depths in the table are for the logs after applying a depth shift to the sea floor. The data was acquired sampling rate of 0.1 m.
Depth shift: A depth shift of 36.7 m was applied to all logs: this amount corresponds to the drilling/logging sea floor depth. Slight discrepancies (<1 m) may exist between the seafloor depths seen in the downhole logs (gamma ray) and those determined by the drillers as clay was present on the seabed frame used during this expedition.
Environmental
corrections: None was applied.
Acoustic data: The data is provided as slowness, expressed in microsec/m and microsec/ft.
The quality of the data is assessed by checking against reasonable values for the logged lithologies and by correspondence between logs affected by the same formation property (e.g. the resistivity log should show similar features to the acoustic log). The quality of the data is good.
The total gamma ray values from the different passes correlate well. The potassium concentration is often extrememely low, beyond the tool detection capability. The gamma ray signature is mostly due to the Uranium and Thorium concentrations.
The compensated sonic log is quite constant, displaying a few spikes probably due to environmental effects such as hole rugosity.
The separation between the different curves of the resistivity tool indicate a permeable formation. The fluctuations observed between 90 and 110 m WSF are assumed to be due to poor hole conditions, though no caliper
log is available for this hole.
A null
value of -999.25 may replace invalid log values.
Additional
information about the drilling and logging operations can be found in the
Operations section of the Downhole Measurement section in the IODP Proceedings of Expedition 347.
For further questions about the data, please contact:
Annick Fehr
RWTH Aachen University
Institute for Applied Geophysics and Geothermal Energy
E-mail: IODP-Germany
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