Community Research and Development Information Service - CORDIS


The report presents a complete description of a temperature logging tool for high temperatures, that utilizes glass fiber transmission. Engineered for field use, the prototype was tested at length both in the laboratory, at the maximum operating limits, and in wells, so far at rather shallow depths (800 m). Well testing was possible thanks to a specially developed system enabling the moving in and out of the tool without twisting the cable. The optical cable that was designed and tested is approximately 960 metres long, the maximum length permitted by the fibre, housed in a flexible stainless steel hose with double outer stranding of INCOLOY. Three other cable lengths are being constructed. When they become available they will enable the system to operate at up to 3500 metres, permitting testing in more critical conditions. The probe is designed for temperature measurements at up to 500 degrees C, with pressures up to 500 bar. These temperatures are withstood by the optical fibre only if stripped of its plastic coating. This operation, however, renders it fragile and makes it necessary to exercise great care when using the system. It is believed, however, that a coated fibre will soon be available on the market that will permit operations at 500 degrees C with low losses. Another operating limit of the probe is its high time constant, which makes it suitable for measuring slow transients rather than recording temperature profiles.

Additional information

Bibliographic Reference: EUR 9325 IT (1984) MF, 26 P., BFR 120, EUROFFICE, LUXEMBOURG, POB 1003
Availability: Can be ordered online
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