Wireline Standard Data Processing

ODP logging contractor: LDEO-BRG
Hole: 1125B
Leg: 181
Location: New Zealand Continental Shelf (SW Pacific Ocean)
Latitude: 42° 32.9791' S
Longitude:178° 9.9876' E
Logging date:October, 1998
Bottom felt: 1377.2 mbrf
Total penetration: 552.1 mbsf
Total core recovered: 511.6 m (92.7 %)

Logging Runs

Logging string 1: DIT/APS/HLDS/HNGS

Wireline heave compensator was used to counter ship heave.

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/APS/HLDS/HNGS: Bottom-hole assembly at 80 mbsf.

Processing

Depth shift: No depth match was necessary because only one logging run was recorded. The original logs have been depth shifted to the sea floor (- 1376 m). ). This amount corresponds to the mudline as seen on the logs, which differs 1.2 m from the "bottom felt" depth given by the drillers (see above).

High-resolution data: Neutron porosity data were recorded at a sampling rate of 5.08 cm.

Quality Control

null value=-999.25. This value may replace invalid recorded log values or results.

During the processing, quality control of the data is mainly performed by cross-correlation of all logging data. Large (>12") and/or irregular borehole affects most recordings, particularly those that require eccentralization (APS, HLDS) and a good contact with the borehole wall.

Data recorded through bottom-hole assembly, such as the gamma ray data above 80 mbsf, should be used qualitatively only because of the attenuation on the incoming signal.

Hole diameter was recorded by the hydraulic caliper on the HLDS tool (LCAL).

Additional information about the logs can be found in the "Explanatory Notes" and Site Chapter, ODP IR Volume 181. For further questions about the logs, please contact:

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