IODP-MSP drilling and logging contractor: ESO and Weatherford Wireline Services
Hole: M0065A
Expedition: 347
Location:
Latitude: 55° 28.094' N
Longitude: 15° 28.631' E
Logging
date:
Sea floor depth (driller's): 87.22 m DRF
Sea
floor depth (logger's): 87.22 m WRF
Total
core recovered:
48.48 m (99.19 % of cored section)
Lithologies: Clay, silt and sand
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/Pass |
Top depth (m WSF)
|
Bottom depth (m W SF)
|
Pipe depth (m WSF)
|
Notes |
|
1. MAI/MCG
|
|
|
|
14 |
|
2. SGS/MCG
|
2 |
|
|
|
|
Hole M0065A was drilled with a 8 1/2 inch bit. In preparation for logging, the hole was circulated with sea water and the drill pipe was pulled back to 14 m WSF. Two tool strings were deployed:
MAI/MCG (Array Induction and Gamma Ray), and SGS/MCG (Total and Spectral Gamma Ray); the MAI/MCG acquired data from about 43.5 m to the sea floor. The SGS/MCG tool string reached only 16 m WSF; after a wiper trip, it was lowered again but reached only 20 m WSF, at which point logging was terminated.
The data was acquired in high resolution mode with a sampling rate of 0.025 m.
Depth shift: A depth shift of 87.22 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.
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.
No caliper measurement was carried out in 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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