ODP logging
contractor: LDEO-BRG
Well name: 676A
Leg: 110
Location: N Barbados Ridge (tropical NW Atlantic)
Latitude: 15° 31.849' N
Longitude: 58° 42.198' W
Logging date: August, 1986
Bottom felt: 5070.1 mbrf (used to depth shift to sea floor)
Total penetration: 310.2 mbsf
Total core recovered: 262.1 m (84.5 %)
Logging
Runs
Logging string 1: DIT/LSS/GR
No information available from logging report about use of wireline heave compensator to counter ship heave.
Bottom-hole
Assembly
The logs show the bottom-hole assembly at 121 mbsf. Any discrepancy with the BHA depth given by the drillers onboard may be due to ship heave and drill string and/or wireline stretch.
Processing
Depth shift: No differential depth shift necessary as only one run was recorded. The original logs have been depth shifted to the sea floor (- 5070.1 m).
Acoustic data processing: Only 23 meters of logs were recorded .The long-spacing (LSS) 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
Only 34 meters of logs were recorded open hole in Hole 676A.
The gamma ray data recorded through bottom-hole assembly should be used qualitatively only because of the attenuation on the incoming signal.
Hole diameter was recorded by the 3-arm mechanical caliper device.
Additional information about the logs can be found in the "Explanatory Notes" and Site Chapter, ODP IR volume 110. For further questions about the logs, please contact:
Cristina
Broglia
Phone: 845-365-8343
Fax: 845-365-3182
E-mail: Cristina Broglia