Temperature Data Processing
ODP logging contractor: LDEO-BRG
Location: Chile Triple Junction (SE Pacific)
Latitude: 45° 53.72' S
Longitude: 75° 51.33' W
Logging date: December, 1991
Bottom felt: 2760 mbrf
Total penetration: 476.1 mbsf
Total core recovered: 169.67 m (46 %)
Water Depth: 2748.9 mbsl
Temperature Tool Used: LDEO-TLT
Depth versus time recording available: NO
Logging string 1: ACT/GST/NGT
Logging string 2: WST
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).
Depth was calculated from a depth/pressure table obtained by synchronizing TLT and GLT or WST tool at the bottom of the hole.
WST stations. Temperatures at individual stations were calculated by fitting an exponential decay curve to the temperature record at each station. Most stations were taken on the way up, except the one at 247 mbsf (on the way down).
Information about the temperature logging operations can be found in the Site Chapter (Operations, Downhole Measurements, and Heat Flow sections), ODP IR volume 141.
E-mail: Cristina Broglia