The international oilfield service industry has used a large variety of sensing devices for the exploration of oil and gas in the last 70 years. These include sensors that range in the measurement of nuclear information, resistivity, acoustic, seismic, E & M fields including most recently optical sensors. The environments are very demanding in temperature, pressure, and vibration which, in general, describes the difficulty in converting current laboratory or commercial sensors for the oilfield industry. Applications where optical sensors have been successfully used and the potential future of fiber optic sensors for this industry will be reviewed.
We describe novel Bragg grating sensors based single mode fiber made with side air holes. Measurements made at 12 kpsi and 100 C produced enhanced sensitivity and reduced thermal dependence compared to normal fiber Bragg gratings.