Chapter 3: Temperature Logging

Production logging began in the late 1930s with the introduction of temperature measurements in oil and gas wells (Schlumberger et al. 1937; Millikan 1941). Spurred by the development of accurate, rapid-resolving resistance thermometers, temperature logging was originally investigated as a means to locate hydrocarbons. It soon became apparent, however, that the differences in thermal properties of hydrocarbons and water were too small to sufficiently affect the overall thermal conductivity of reservoir rocks to distinguish hydrocarbon-bearing zones from nonproductive intervals (Guyod 1946a, 1946b, 1946c, 1946d, 1946e, 1946f, 1946g).

Although the original application of temperature logs was not particularly successful, temperature logging was soon recognized as a means to evaluate production-well characteristics by measuring and analyzing anomalous temperature behavior. Temperature logging applications described in early papers (Schlumberger et al. 1937; Millikan 1941; Guyod 1946a, 1946b, 1946c, 1946d, 1946e, 1946f, 1946g; Halbouty 1939; Goins and Dawson 1953; Kunz and Tixier 1955) included the location of gas entries, the detection of casing leaks and fluid movement behind casing, the location of lost-circulation zones, and the evaluation of cement placement. Temperature logs are still used for these applications and others, but the most common use now is qualitative identification of injection or production zones. Despite the many other logs that have been developed, the temperature log remains the workhorse of the production logging stable. This is primarily because of its reliability; no matter what the wellbore flow conditions, temperature can be accurately measured. In addition, the temperature log tends to reflect the long-term behavior of a well, not only current conditions.