Fiber Sensor Research to Improve Oil Reservoir Measurement and Monitoring

Virginia Tech to Improve Accuracy, Speed,
Efficiency and Reliability of Remotely Sensed Data

Fiber optics — strands of glass, each as thin as a human hair, that carry information using pulses of laser-emitted light — are revolutionizing the way data is sent and received. Like the telecommunications and computer industries, the petroleum industry stands to benefit from the speed and reliability offered by fiber optic technology.

To help advance these benefits, the Department of Energy (DOE) has awarded a grant to the Virginia Polytechnic Institute (VPI) Fiber & Electro-Optics Research Center in Blacksburg, VA. The Center, the largest university fiber sensor research and development group in the world, will develop a new fiber sensor technology that can withstand the harsh "downhole" environment of an oil well and transmit vital well and reservoir data to operators on the surface faster, more accurately and reliably, and with greater economy of operation than current technology.

DOE will provide VPI with $2.0 million in federal petroleum research funds, and VPI will contribute an additional $650,000 for the 42-month research project.

The VPI project is expected to be especially beneficial for many smaller, independent oil producers who need such technological advances but cannot afford to carry out this type of high-risk research themselves. Especially with low oil prices expected to continue into the foreseeable future, the need increases for more accurate data on "downhole" conditions that can be used to increase the flow of oil from difficult-to-produce reservoirs.

VPI's project, Optical Fiber Sensor Technologies for Efficient and Economic Oil Recovery, will expand on the university's recent breakthroughs in optical fiber-based sensor technology. The goal of the new project is to develop cost-effective, reliable fiber sensors for downhole measurement of temperature, pressure, fluid flow and acoustic waves -- the type of routine reservoir data that is essential if the maximum amount of crude oil is to be produced from oil fields.

Currently, oil producers use relatively bulky mechanical measuring technology that requires encased units to be lowered down into and retrieved from well bores using cables, hoists, and other equipment. These devices are expensive to operate and are subject to breakdowns in operation. The electrical conduits in these devices are often subject to interference and signal degradation which lowers the quality of the data.

VPI's fiber optics technology will use a small sensor unit that is much more easily lowered and retrieved, less expensive to operate and will be considerably less prone to breakdowns. The fiber cable/sensor combination provides much improved accuracy of data, greater ease of operation and data acquisition, and the unit is self calibrated for greater reliability.

In VPI's "Self-Calibrated Interferometric/Intensity-Based (SCIIB) Fiber Sensors," light traveling through an optical fiber to a sensing device is reflected back along the fiber in two channels with separate wave lengths 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 the sensor is measuring in the reservoir. Because VPI's unique design and signal processing system eliminates signal power losses inherent in previous systems, the SCIIB unit is expected to provide high resolution, accuracy, speed, absolute measurement, design flexibility and self calibration.

The project will involve participation by the University of Tulsa for laboratory sensor testing, Chevron for field testing, and Baker Hughes for incorporation of the developed sensors in commercial products. Following the full team's specification of technical requirements, VPI will fabricate the sensors and specially coated fibers, design schemes for multiple-task operation, and complete the instrumentation necessary to coordinate the entire system. After the sensor instrumentation is tested at the University of Tulsa, the system will be deployed at Chevron's Coalinga, California facilities, the world's largest oil field testing site, with support from Baker Hughes.

Results from the field test analysis of sensor performance and the relationship between reservoir measurements and production will be provided to the oil industry in a measurement-based database. VPI and Baker Hughes will then develop a plan for commercialization of the technologies in Baker Hughes future products to best benefit the U.S. oil industry.

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For more information, contact:
Hattie Wolfe, U.S. Department of Energy, Office of Fossil Energy Headquarters, (202)586-6503; e-mail address: hattie.wolfe@hq.doe.gov

Technical Contact:
Herb Tiedemann, Technology Transfer Officer, National Petroleum Technology Office, (918) 699-2017; e-mail address: htiedema@npto.doe.gov