Temperature Data Processing
ODP logging
contractor: LDEO-BRG
Hole: 856-H
Leg: 139
Location: Middle Valley, Juan de Fuca Ridge (NE Pacific Ocean)
Latitude: 48° 26.020' N
Longitude: 128° 40.859' W
Logging date: July, 1991
Bottom felt: 2434.5 mbrf (used for depth shift to sea floor)
Total penetration: 93.8 mbsf
Total core recovered: 18.9 m (20 %)
Water Depth: 2434.5 mbrf
Temperature
Tool Used: LDEO-TLT
Depth versus time recording available: NO
Logging
Runs
Logging string: DIT/SDT/NGT
No wireline heave compensator was used to counter ship heave.
The LDEO-TLT tool is a self-contained, high precision, low-temperature logging tool that is attached to the bottom of the Schlumberger tool strings. The tool provides two temperature measurements (in degree Celsius, recorded by a fast-response and a slow-response thermistor. The fast-response thermistor, though low in accuracy, is able to detect sudden, small temperature excursions caused by fluid flow between the formation and the borehole. The highly accurate, slow-response thermistor can be used to estimate heat flow. Pressure and the two temperature measurements are recorded as a function of time: conversion to depth can be based on the pressure reading (Legs 123-157) or, preferably, on simultaneous recording (by Schlumberger) of depth and time (Legs 159-181).
A pressure-depth relationship was originally used to calculate depth, but no documentation is available about the actual calculation.
Information about the temperature logging operations can be found in the Site Chapter (Operations, Downhole Measurements, and Heat Flow sections), ODP IR volume 139.
Cristina Broglia
Phone: 845-365-8343
Fax: 845-365-3182
E-mail: Cristina Broglia