Wireline Standard Data Processing

ODP Logging Contractor: LDEO-BRG

Hole: 973D

Leg: 160

Location: Hellenic Accretionary Prism (Mediterranean Sea)

Latitude: 35° 46.824' N

Longitude: 18° 56.824' E

Logging Date: April, 1995

Bottom Felt: 3705.6 mbrf (used for depth shift to sea floor)

Total Penetration: 152.6 mbsf

Total Core Recovered: 64.1 m (85 %)

Logging Runs

Logging String #1: DIT/SDT/NGT

Wireline heave compensator was used to counter ship heave resulting from the mild sea conditions.

Bottom-hole Assembly

The following bottom hole assembly depths are as they appear on the logs after differential depth shift (see DEPTH SHIFT section) and depth shift to the sea floor. As such, there might be a discrepancy with the original depths given by the drillers onboard. Possible reasons for depth discrepancies are ship heave, use of wireline heave compensator, and drill string and/or wireline stretch.

DIT/SDT-LSS/NGT: bottom hole assembly at ~ 52.5 mbsf.

Processing

Depth shift: No differential depth shift required. All original logs have been depth shifted to the sea floor (- 3705.6 m).

Gamma-ray processing: Data have been processed to correct for borehole size and type of drilling fluid.

Acoustic data processing: The array sonic tool was operated in standard depth-derived borehole compensated mode, including long-spacing (8-10-10-12') logs. The sonic logs have been processed to eliminate some of the noise and cycle skipping experienced during the recording. Using two sets of the four transit time measurements and proper depth justification, four independent measurements over a -2ft interval centered on the depth of interest are determined, each based on the difference between a pair of transmitters and receivers. The program discards any transit time that is negative or falls outside a range of meaningful values selected by the processor.

Quality Control

null value=-999.25. This value generally appears in discrete core measurement files and also it may replace recorded log values or results which are considered invalid (ex. processed sonic data).

Data recorded through bottom hole assembly, such as the NGT data above 52.5 mbsf should be used qualitatively only because of the attenuation on the incoming signal.

No hole diameter measurement was recorded.

Details of standard shore-based processing procedures are found in the "Explanatory Notes" chapter, ODP IR Volume 160. For further information about the logs, please contact:

Cristina Broglia
Phone: 845-365-8343
Fax: 845-365-3182
E-mail: Cristina Broglia