Patent ID: 9110018
Filing Date: 2015-08-18
Classification: E21B,G01D,G01N

Abstract:
1. A distributed optical fibre sensor for determining one or more parameters as functions of position in opposite directions around a loop of sensing optical fibre from properties of probe light backscattered within the sensing optical fibre, the sensor comprising: a probe light source arranged to generate probe light pulses each at one of two optical wavelengths; a coupler arranged to receive the probe light pulses from the probe light source and to direct pulses of each wavelength into the sensing optical fibre loop in a different corresponding direction, and to collect probe light backscattered within the sensing optical fibre; a detector arranged to receive the collected backscattered light and to separately detect light of each of said different wavelengths in said collected backscattered light; and an analyser arranged to determine said one or more parameters as functions of position in each direction along the sensing optical fibre from said detected backscattered light of each corresponding wavelength.