# US 2016/0259083 A1 · Distributed sensing in an optical fiber network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0259083 A1 - Document ID: US20160259083A1 - Status: Published application - Kind: A1 - Application number: 14/389,964 - Filed: 2013-10-17 - Published: 2016-09-08 - Earliest claimed: 2013-10-17 - Assignees: Halliburton Energy Services, Inc. - Applicants: Halliburton Energy Services, Inc. - Inventors: David Andrew Barfoot; Michel Joseph LeBlanc; Neal Gregory Skinner - Web page: https://patentgrep.com/patent/US20160259083A1 ## CPC - G01V 8/16: using optical fibres - E21B 43/26: by forming crevices or fractures - E21B 47/00: Survey of boreholes or wells (monitoring pressure or flow of drilling fluid E21B21/08) - E21B 47/07: Temperature - E21B 47/135: using light waves, e.g. infrared or ultraviolet waves - G01L 1/246: {using integrated gratings, e.g. Bragg gratings} - H04B 10/27: Arrangements for networking - H04J 14/08: Time-division multiplex systems - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - H04B: TRANSMISSION - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) ## Abstract A distributed optical fiber sensing system is provided. The system can include an interrogator, a transmission optical fiber, a sensing optical fiber, and a reflector. Each of the transmission optical fiber and the sensing optical fiber includes at least one circulator. The reflector is optically coupled to the transmission optical fiber for sensing separate regions along the sensing optical fiber. ## Claims ### Claim 1 (canceled) ### Claim 2 (depends on 7) The system of claim 7, wherein the sensing optical fiber is divided into the separate regions, each region having a smaller length than a total length of the sensing optical fiber. ### Claim 3 (depends on 7) The system of claim 7, wherein the at least one circulator is a three-port circulator. ### Claim 4 (depends on 3) The system of claim 3, further comprising a linking optical fiber between a first circulator of the transmission optical fiber and a second circulator of the sensing optical fiber. ### Claim 5 (depends on 7) The system of claim 7, wherein the at least one circulator is a four-port circulator and is coupled to both the transmission optical fiber and the sensing optical fiber. ### Claim 6 (canceled) ### Claim 7 A system comprising: an interrogator that includes an optical transmitter and an optical receiver; a transmission optical fiber and a sensing optical fiber, each of the transmission optical fiber and the sensing optical fiber including at least one circulator; and a reflector optically coupled to the transmission optical fiber with which separate regions along the sensing optical fiber are sensed, wherein the reflector includes a plurality of reflectors, each reflector of the plurality of reflectors being associated with a separate region and with a distinctive optical wavelength, wherein the reflector associated with a first wavelength is responsive to an optical signal in the first wavelength from the optical transmitter by reflecting a reflected optical signal that includes the optical signal to a first circulator preceding the reflector along the transmission optical fiber and is transparent to optical signals of wavelengths other than the first wavelength by allowing the optical signals to pass through the reflector, wherein the first circulator is responsive to the reflected optical signal by routing the reflected optical signal to a second circulator of the sensing optical fiber for creating a backscatter optical signal with a selected region to be sensed and that is received by the optical receiver and measured. ### Claim 8 (depends on 7) The system of claim 7, wherein the second circulator is operable for routing the reflected optical signal away from the optical receiver toward a sensing region and allowing the backscatter optical signal to pass toward the optical receiver. ### Claim 9 (depends on 7) The system of claim 7, wherein the at least one circulator and the reflector are disposed in a wellbore. ### Claim 10 (depends on 7) The system of claim 7, wherein the sensing fiber has a higher backscattering coefficient than the transmission fiber. ### Claim 11 (depends on 7) The system of claim 7, wherein the optical transmitter is operable for outputting a signal that includes multiple wavelengths and the optical receiver is operable for receiving backscatter signals at different wavelengths for simultaneously sensing multiple regions of the sensing fiber. ### Claim 12 (depends on 7) The system of claim 7, wherein the optical transmitter is operable for outputting a signal having a broadband spectrum and the optical receiver is operable for receiving backscatter signals at different wavelengths for simultaneously sensing multiple regions of the sensing fiber. ### Claim 13 A method, comprising: transmitting an optical signal having a selected optical wavelength associated with a desired region onto a transmission optical fiber; reflecting the optical signal by a reflector of the transmission optical fiber and that is associated with the selected optical wavelength to generate a reflected optical signal; routing, by a circulator that immediately precedes the reflector, the reflected optical signal to a sensing optical fiber divided into multiple regions that includes the desired region; routing the reflected optical signal into the desired region to generate a backscatter signal; and receiving the backscatter signal from the sensing optical fiber for measuring a parameter of the desired region. ### Claim 14 (depends on 13) The method of claim 13, further comprising: allowing the optical signal to pass through at least one reflector o associated with a different optical wavelength than the selected optical wavelength. ### Claim 15 (depends on 13) The method of claim 13, wherein routing the reflected optical signal into the desired region to generate the backscatter signal includes routing the reflected optical signal by a three-port circulator of the sensing optical fiber. ### Claim 16 (depends on 13) The method of claim 13, wherein routing the reflected optical signal into the desired region to generate the backscatter signal includes routing the reflected optical signal by the circulator that immediately precedes the reflector, the circulator being a four-port circulator that is coupled to the transmission optical fiber and the sensing optical fiber. ### Claim 17 (depends on 13) The method of claim 13, wherein the transmission fiber includes a plurality of reflectors, wherein each reflector is associated with a separate region and with a distinctive optical wavelength. ### Claim 18 A system comprising: a transmission optical fiber; a sensing optical fiber divided into separate regions; a reflector associated with an optical wavelength and coupled to the transmission optical fiber; and a circulator immediately preceding the reflector for routing a reflected optical signal from the reflector to a selected region of the separate regions in the sensing optical fiber with which the selected region can be sensed. ### Claim 19 (depends on 18) The system of claim 18, wherein at least part of the transmission optical fiber and at least part of the sensing optical fiber are located in a wellbore through a subterranean formation. ### Claim 20 (depends on 19) The system of claim 19, further comprising an interrogator with an optical transmitter coupled to the transmission optical fiber and an optical receiver coupled to the sensing optical fiber. ### Claim 21 (depends on 20) The system of claim 20, wherein the optical receiver is operable for receiving a backscatter signal generated in the selected region by the reflected optical signal traveling away from the optical receiver.