LWD Standard Data Processing

ODP logging contractor: LDEO-BRG
Hole: 1167B
Leg: 188
Location: Prydz Bay (Antarctic Ocean)
Latitude: 66° 24.0' S
Longitude: 72° 17.0' E
Logging date: February 28-29, 2000
Bottom felt: 1652 mbrf
Total penetration: 260 mbsf

Logging Runs

Logging string 1: CDR/MWD (Logging While Drilling)

Hole 1167B was logged while drilling. The rate of penetration averaged 21 m/hr. The CDR recorded resistivity and natural gamma ray logs in memory; the MWD Power-Pulse tool logged drilling parameters such as weight-on-bit and torque and transmitted the data to the ship in real time.

Processing

Depth shift: The original logs were shifted to the sea floor (-1652m). The sea floor depth is determined by the step in gamma ray values at the sediment-water interface.

Gamma-ray processing: Only the total gamma ray log (GR) is available at present. Spectral gamma ray measurements are being re-processed by Anadrill after problems were found in the initial logs.

Quality Control

During the processing, quality control of the data is mainly performed by cross-correlation of all logging data. Comparison to the wireline logs over the equivalent depth interval in Hole 1167A show that whereas the wireline measurements are affected by hole wash-out in places, the LWD measurements are not. Where the wireline hole is good, the LWD logs compare favorably to the wireline logs.

Additional information about the logs can be found in the "Explanatory Notes" and Site Chapter, ODP IR Volume 188. For further questions about the logs, please contact:

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