IODP-MSP drilling and logging contractor: ESO and Weatherford Wireline Services

Hole: M0060B

Expedition: 347

Location: Anholt Locht (Baltic Sea)

Latitude: 56° 37.204' N

Longitude: 11° 40.229' E

Logging date: October 1, 2013

Sea floor depth (driller's): 31.5 m DRF

Sea floor depth (logger's): 31.5 m WRF

Total penetration: 85.7 m DSF

Total core recovered:  87.62 m (100 % of cored section)

Lithologies: sand and clay

 

 

 

 

 

Data

 

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.

 

Logging Runs

 

Tool string

Run/Pass

Top depth

(m WSF)

Bottom depth

(m WSF)

Pipe depth

(m WSF)

Notes

1. MAI/MCG

1

0

67.3

15

 

2. MSS/SGS/MCG

2

0

61.7

15

 

3. CMI/MCG

3

0

57.5

15

 

 

 

Hole M0060B 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 15 m WSF. The first tool string (MAI/MCG), Array Induction and Gamma Ray, reached 67 m WSF, where the uplog started. The second tool string, MSS/SGS/MCG, which included Total and Spectral Gamma Ray and a Compensated Sonic Tool, acquired data from 61 m WSF upward. The last tool string (CMI/MCG, MicroImager and Gamma Ray) acquired data from 61 m WSF uplog.

 

The depths in the table are for the logs after applying a depth shift to the sea floor.

The data was acquired with a sampling rate of 0.1 m. The CMI data was sampled every 0.001 m.

 

 

Processing

 

Depth shift: A depth shift of 31.5 m was applied to all logs: this amount corresponds to the drilling/logging sea floor depth. The original logs were depth adjusted to the seafloor using the drillers depth to seafloor. 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.

 

Quality Control

 

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 logs acquired at Hole M0062D 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 hole size was measured by the caliper tool on the CMI, which provides two orthogonal measurements of the hole diameter.

 

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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