The harsh environment during in situ heating of oil shale significantly impacts the structure and materials of downhole heaters. This paper presents the design of an online temperature and corrosion monitoring system for downhole in situ heaters in oil shale wells, utilizing thermocouple technology for temperature monitoring and fiber optic grating technology for corrosion monitoring. The system enables high-precision temperature measurements up to 500 °C using thermocouples and real-time, high-sensitivity corrosion monitoring via fiber optic grating technology. The measured corrosion rates are consistent with those obtained from the weight loss method and inductive probe method but exhibit faster response times. The monitoring system adopts oil pipes as the lowering carrier, with fiber optic grating installed along the horizontal section. Data are efficiently transmitted through wired transmission technology, combined with a short-section mounting structure and a nano-aerogel thermal insulation protection device to ensure the system’s applicability and stability under high-temperature and high-pressure conditions. The online monitoring system developed in this paper provides a solution for designing and monitoring the performance of oil shale in situ heaters in the field.
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