Special Report Interdisciplinary Activities and Programs

April 1998

		Fiber Sensors Go For The Black Gold Department fiber optics and photonics researchers have long been working with engineers and scientists from other fields, developing sensors and actuators for applications that range from smart airplane wings to biosensors. Thanks to recent developments by a research team led by Professor Anbo Wang, oil wells and harsh environments have been added to the list. Wang's team recently developed self-calibrated interferometric/intensity-based (SCIIB) sensors, which for the first time successfully combine fiber interferometry and intensity-modulated devices together in a single sensor system. The result is a fiber sensor that can withstand the high-temperature, high-pressure harsh environments of the petrochemical industry. "Until now, no reliable sensor has been available to monitor the oil well pump," Wang said. "If an operator wanted to measure the temperature, the sensor would only last 300 hours after installation - and it could cost $1 million to pull the head and replace the sensor." The lack of reliable sensors means that about two-thirds of all discovered oil is left in the ground, he explained. "Without information about what is going on in the well - and in the reservoir - it is usually economical to only recover one-third of the available oil." This situation could change with reliable sensors. Wang's SCIIB device can measure both temperature and pressure. It is very small, about 300 microns, can withstand temperatures up to 800° C, pressures of up to 10,000 p.s.i., and is expected to last multiple years in service. It also can maintain an ultra high resolution and accuracy as far away as 10 km. "The most important feature of the new device is that it provides very high resolution, and high accuracy, with a high-frequency response, and is self-calibrating at the same time," Wang said. Team Effort In order to develop the sensors, Wang's team had to understand a number of issues in non-EE areas, including the oil recovery process, oil/fiber interaction, and sensor materials and packaging. "The geologists and petroleum engineers involved in the project were very helpful in this way," Wang said. "We knew sensors, but not petroleum, and they knew petroleum, but not sensors." New Laboratory Established Work on the new sensors will continue in the Enabling Photonics Technology Laboratory in the New Engineering Building. "We are currently investigating new methods for the fabrication of the SCIIB sensors with better performance and lower cost," he said. "This new sensor technology could be important not just to the petroleum industry, but other industries such as power, aerospace, and mining, where harsh environments often make conventional sensors difficult to apply." The new photonics laboratory was established as a facility where researchers from many disciplines can gather to work on industrial applications. "In order to fully exploit the technical potential offered by the SCIIB technology, we need to continue to develop the multidisciplinary research areas of materials, fiber optics, sensor packaging and high-speed digital signal processing - as well as the application fields where harsh environment sensors are needed," Wang said. Currently Wang's team of 12 staff and graduate students is working in three research areas, including optical fiber sensors, holographic 3-D imaging, and special optical communications devices and systems. The work has been supported by the National Science Foundation (NSF), the Air Force Office of Scientific Research (AFOSR), the Electric Power Research Institute (EPRI), the Virginia Center for Innovative Technology (CIT), and a number of domestic and foreign companies.

The Bradley Department
of Electrical and Computer Engineering
Virginia Tech

Last Updated, May 10, 1998

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