Patent ID: 9733120
Date: 2017-08-15
CPC Classifications: E21B,G01D,G01H,G01N

Claim:
1. A system for monitoring regions of interest for occurrences that generate acoustic perturbations, comprising: a. an optical fiber span positioned into a region of interest; b. a light source for generating a continuous coherent signal of a pre-determined wavelength into the optical fiber; c. a pseudo-random binary code sequence generator driven by a master clock; d. an optical modulator having first and second ports for receiving the primary coherent light signal from the light source and a generated pseudo-random binary codes from the pseudo-random binary code sequence generator to produce a modulated light signal; e. wherein the pseudo-random binary sequence codes are binary sequences of ones and negative ones; f. and wherein the pseudo-random binary sequence codes are periodic with a period of T g. and wherein the fiber optic cable length L, the desired spatial sampling Δ  where ρ is small compared to  and h. an optical circulator/coupler to receive the modulated light signal from the optical modulator and pass it into the optical fiber span positioned into the region of interest; i. a detector system driven by the master clock for de-modulating, correlating, and de-multiplexing returned backscattered Rayleigh signals from the optical fiber span positioned into the region of interest, wherein the detector system has a processor to detect coherent Rayleigh noise generated by the optical fiber span positioned in the region of interest to identify acoustic events in the regions of interest; and j. wherein the returned backscattered Rayleigh signals from the optical fiber span positioned into the region of interest are directed to the detector system by the optical circulator/coupler.