Downhole temperature acquisition system installed in an offshore Canadian Arctic well



A long-standing problem in measuring the terrestrial heat flow beneath the ocean floors has been the acquisition of deep temperature information comparable to that more readily obtained on the continents. While rather sophisticated sediment temperature and in situ thermal conductivity probes have evolved over the years from the simplicity of the Bullard and Ewing designs [Langseth, 1965; Lister, 1979; Hyndman et al., 1979], they are limited to a few meters of penetration. The improved accuracy and detail afforded by these later designs have revealed dynamic phenomena that are crucial to an understanding of processes in the ocean lithosphere [e.g., Anderson et al., 1979; Langseth and Herman, 1981] and that can best be studied in deep holes over an extended period of time. Recently, a prototype system has been installed in an offshore petroleum exploration well in the Canadian Arctic to demonstrate the technology of measuring precise wellbore temperatures to hundreds of meters depth at frequent intervals over a period of several years.