This paper was prepared for the SPE Symposium on Mechanical Engineering Aspects of Drilling and Production to be held in Fort Worth, Tex., March 5–7, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.


A new, "a priori" differential temperature survey has been developed which overcomes the flaws that made earlier systems of little use. Although every portion of the system employs new techniques, the key to its new and surprising capabilities is the memorizing and comparing of two absolute measurements made by the same sensor, on the same run into a well.

This new tool has successfully performed tasks not previously assigned to temperature equipment, including; behind-pipe oil-finding and oil-water contact location injection profiles fracture treatment evaluation, lost circulation location and production profiles.

A priori profiles have not only shown the relationship between fluid input and shut-in temperature slope, but have led us to theorize that in profile situations, a true temperature distribution probably exists in the macro-annulus, but that it must be moved into the near annulus, or the borehole, in order to be measured.

Further study has caused us to doubt the common idea that all of an intake zone takes fluid of similar temperature, and to theorize that each increment of intake zone takes fluid of a different temperature. To provide this temperature spectrum fluid column thermodynamics are envisioned that create a radial temperature gradient whereby the topmost intake increment takes its fluid from the warmest outer annulus of the column, while the coolest, central fluid continues to the deepest intake increment. Laboratory experiments indicate that such a distribution is entirely possible.


A few years ago the first attempts were made to employ a differential temperature tool; that is a tool that seeks to measure the difference in temperature between two proximate points in the bore hole.

This content is only available via PDF.