The Protherma tool is designed specifically for operation in geothermal and other high-temperature wells. The tool contains essential production logging sensors for pressure, temperature and flow rate measurements, as well as natural gamma ray for correlating geological features and a casing collar locator (CCL). The tool can be operated on slickline with the addition of the memory module, or in surface readout (SRO) mode on e-line.

Pressure measurements are made using a quartz pressure sensor, and a fast-response resistance temperature detector (RTD) is exposed to the wellbore to accurately detect temperature variations. Flow rate is measured using interchangeable flow meters and impellers. The electronics section is encased within a pressure housing which includes an integrated scintillation-based gamma detector and a casing collar locator.

The tool can operate for up to 6 hours at 300°C in real-time mode, and up to 4 hours at 350°C in memory mode. All material used within the downhole suite meet NACE MRO175 specifications for corrosive wellbore media.