Field testing of an optical fiber temperature sensor in a geothermal well

Abstract

A program has been initiated for developing and field testing optical fiber sensors to monitor in situ physical and chemical parameters in highly corrosive environments, such as geothermal wells, oil wells, and hot-water boiler reactors. The difficulty of sampling hot geothermal fluids or reliably measuring physical and chemical properties of brines in wells limites our understanding of in situ conditions in geothermal fields. In this communication, the authors report a test of the concept of utilizing optical fiber based sensors by measuring the temperature profile of a geothermal steam well. The purpose of this work is not only to demonstrate that a temperature optical chemical sensor (optrode) can be used to obtain real-time information from a geothermal well, but also that great potential of the optrodes can be exploited for measuring physical and chemical parameters in the field. It is believed that this is the first real-time, in situ, geothermal well measurement to have been made using an optical fiber sensor.