Department of Energy awards downhole fiber sensor project

The U.S. Department of Energy has awarded Virginia Polytechnic Institute's Fiber & Electro-Optics Research Center, Blacksburg, Va., a grant to develop fiber sensor technology that can withstand the harsh downhole environment of an oil well. DOE said that the project will develop fiber sensors for measurement of temperature, pressure, fluid flow, and acoustic waves.

Nov. 30, 1998

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DOE said that the project will develop fiber sensors for measurement of temperature, pressure, fluid flow, and acoustic waves.

Noting that current measuring technology requires encased units to be lowered into well bores, DOE said that the devices are expensive to operate, subject to breakdowns, and their electrical conduits are often subject to interference and signal degradation.

New technology

DOE said VPI's fiber optics technology uses a small sensor unit that is more easily lowered and retrieved, less expensive to operate, and is less prone to breakdowns. It said that the fiber cable/sensor combination provides more accurate data and that the unit is self-calibrated.

DOE said that, in the VPI system, light traveling through an optical fiber to a sensing device is reflected back along the fiber-in two channels with separate wavelengths-to a signal processing unit. The processor calculates interference between the two signals to determine the amount of displacement in the sensor element, caused by heat, pressure, fluid flow, or some other variable that the sensor is measuring in the reservoir.

DOE said that VPI's design eliminates signal power losses inherent in previous systems.

After VPI develops the system, the University of Tulsa will test the sensor instrumentation. It then will be tested in Chevron Corp.'s Coalinga, Calif., oil field testing site, with support from Baker Hughes Co.

Data about the system will be provided to the oil industry. VPI and Baker Hughes plan to offer the technology in future Baker Hughes products. DOE will fund $2 million of the 42-month project and the university another $650,000.