WIRELINE LOGGING PLAN
The Leg 184 logging plan has been designed to provide (1) complete stratigraphic coverage, especially useful if core recovery is incomplete; (2) proxy data not available from core measurements, such as resistivity and yields of K, U, and Th; and (3) in situ sonic velocity for the construction of synthetic seismograms. All sites drilled to a depth greater than 400 m will be logged using the following three tool strings (see: http://www.ldeo.columbia.edu/BRG/new_kiosk.html for additional information on the tools):
A. "Triple-combo" toolstring, which includes: (1) the Dual Induction Tool (DITE) that measures resistivity from deep and shallow induction; (2) the Accelerator Porosity Sonde (APS) to measure porosity from epithermal neutron measurements; and (3) the Hostile Environment Litho-Density Sonde (HLDS) that measures bulk density from Compton scattering and general lithology from the photoelectric effect. The Hostile Environment Natural Gamma Ray Sonde (HNGS) that measures total natural gamma radiation and K, U, Th yields, and the LDEO Temperature Logging Tool (TLT) that measures borehole fluid temperature, are added to this toolstring.
B. "FMS-Sonic" toolstring which includes (1) the Formation Microscanner (FMS) that includes the General Purpose Inclinometry Tool (GPIT) and measures micro-resistivity at cm resolution; (2) the Dipole Sonic imager (DSI) that measures compressional and shear wave velocity, as well as cross dipole and Stoneley waveforms.
C. Geologic High-resolution Magnetic Tool (GHMT), which includes the Nuclear Magnetic Remanence Sonde (NMRS) to measure the total magnetic field, and the Susceptibility Measurement Sonde (SUMS) to measure the magnetic susceptibility from induction.
All tool names are trademarks of Schlumberger, except the TLT.
Use of the FMS-Sonic and GHMT toolstrings is contingent on hole conditions as estimated from the caliper measurements with the triple-combo string (always used for the first run), and the general course of the previous logging run. Estimated logging times for all three runs vary from 28 to 38 hr for the each of the Leg 184 sites.