High Pressure-High Temperature Well Logging and Measurements as an Emerging Technology for Geothermal Development

Abstract

Temperature of geothermal fluid or reservoir is directly related to the economic feasibility in a geothermal system. High temperature geothermal systems (T > 250°C or higher) are mostly associated with active volcanics. Volcanic-related geothermal systems represent a significant potential energy resources. Some countries with volcanic activities are trying to develop extremely high temperature from supercritical or ductile regions, such as IDDP and DEEPEGS projects in Iceland, DESCRAMBLE project in Italy, JBBP project in Japan, and HADES project in New Zealand. Exploitation of such supercritical geothermal system demands novel downhole logging tools, which can give valuable information on the formation properties, inspection of well completion, and reservoir characteristics. In this work, high temperature and high pressure logging tools were firstly reviewed; not only that are currently available on the market from tool developers and service companies, but that are being developed by different project worldwide, and finally discussion on the future tool development was done. Future tool designs will strongly rely on the available material and further material improvements when they become available. Currently some advanced tools tolerating up to 260°C and PT sensor can now be measured up to 300°C in unshield condition and expected to reach the IPGT’s target temperature of 600°C in the near future with the aid of advances in new electronics materials and active heat shielded technology.