| Title | Recent Developments in Fiber Optic Sensor Technology for High Temperature Well Monitoring |
|---|---|
| Authors | Sanders, Paul E.; MacDougall, Trevor W. |
| Year | 2009 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Geothermal Logging Tools; High Temperature Pressure and Temperature Sensors; Optical Distributed Temperature Sensors; Fiber Optic Sensors |
| Abstract | New developments in fiber optic sensor technology for high temperature well monitoring have been driven by their use in thermal recovery wells in the Canadian oilsands industry. These developments have resolved hydrogen-induced optical failure of fiber optic systems deployed in steam-assisted gravity drainage (SAGD) wells operating up to 300°C. This same hydrogen failure was likewise experienced in deploying fiber optic sensors in geothermal wells at similar temperatures. High temperature upgrade of a suite of downhole optical sensors is enabled through refinement of high temperature, hydrogen-tolerant optical sensing fibers and cables. This paper will review hydrogen effects on optical systems operating in high temperature, hydrogen-rich well environments, and mitigation of these effects through use of pure silica optical fibers. Field results for optical distributed temperature sensors and point pressure sensors operating on these fibers in high temperature SAGD wells validate the use of these sensors in these environments, and demonstrate reliability and good correlation to downhole thermal references. These results, along with design features and operating aspects for these systems will be discussed to show the technology now well-positioned for use in high temperature geothermal well monitoring. |