Research On In-casing Continuous Fiber-distributed Temperature Measurement Technique And Its Application

Accurate temperature measurements for geological data interpretation and oil wellmonitoring plays an important role in Oilfield production. At present,in-casing temperaturemonitoring technology include electronic and mechanical. These technologies only tomonitor the temperature of a deep point in a moment, not to monitor the temperature on thecontinuous depth profiles of the same time.Research on in-casing continuous fiber-distributed temperature measurement techniqueand its application is the use of real-time distributed monitoring of fiber-optic sensors on thetemperature within the wellbore. Selected according to the requirements of the workcharacteristics of the various types of sensors and oil casing annulus temperature fibergrating sensors, fiber-optic Brillouin sensors and fiber optic sensor based on Ramanscattering study to carry out field trials, test solved the core of the optical fiber lineshielding layer, protective layer combinations and on-site fiber cutting, welding and othertechnical issues. Optimized based on Raman scattering fiber sensor test accuracy can reach±0.5°C, sensor monitoring range of-40~120°C, the spatial resolution of0.5m.Through field trials, the outer wall of the fixed fiber tubing, each tubing coupling toinstall the fiber protective shield, the fiber with the job down into the oil ring in the air laidprocess, the fiber optic sensors do not interfere with the well temperature fieldreal-timemonitoring wells temperature distribution law, to verify the feasibility of a fiber optic sensormonitoring technology used in distributed continuous monitoring of temperature in thecasing, a true reflection of the temperature changes in the wellbore, the technology to meetthe well temperature field measurement requirements. Measured by the test welltemperature data for future analysis of oil well production performance and well hot washeffect to determine the hot wash parameters have a very important guiding significance, andbroad application prospects.