Distributed Temperature Sensing in the Oil and Gas Industry - Insights and Perspectives

The temperature as a scalar quantity is a parameter which can be measured in a borehole without great efforts. Humboldt was one of the first to look at temperatures below the surface, and systematic measurements of temperatures exist from the early 1.9th century. However, the interpretation of downhole temperature measurements is often complex and needs an integrative approach. "Distributed Temperature Sensing" DTS is based on optical time-domain reflectometry and meanwhile an innovative and well established technology for the registration of a temperature field and its temporal and spatial distribution along a fibre optical cable. The DTS-market has developed rapid over the years, and DTS-measurements are an integral part in the Oil & Gas industry. Because of its secure and reliable use even in hostile environments (HT, HP, H2S, explosion protection area), an increase in the use of DTS-measurements can be expected. DTS-measurements can be used in a wide range of applications, such as (and not restricted to): - Detection and localization of fluids in open borehole - Detection and localization of fluids behind the casing - Detection and localization of leakages in casing and production string - Detection and localization of the top of cement and setting process - Proof of mechanical integrity of completions - Monitoring of pipelines and installations. For all the measurements, a high spatial and temperature resolution down to 0.15 m and 0.1 degrees C resp. can be realized. Case studies with appropriate interpretations are demonstrating the versatile possibilities for DTS-measurements, and further developments for the use of fiber optic measurements in the Oil Er Gas industry are discussed. The use of fibre optic cables is not limited to temperature measurements, also acoustic vibrations can be detected and used for seismic measurements (Distributed Acoustic Sensing).