Patent ID: 11867629
Assignee: SAUDI ARABIAN OIL COMPANY
Field: Measurement (Instruments)
Classification: CPC G  E | IPC E  G

Claim 11:
12. A method for well monitoring, the method comprising:
inserting a sensing system downhole to a desired depth, wherein the sensing system comprising an evanescent field sensing element that is in direct contact with a downhole fluid and provides partial or total internal reflection of a beam which interacts with the downhole fluid at an interface between the evanescent field sensing element and the downhole fluid;
wherein the sensing system comprises:
at least one light source, having at least one frequency comb generator, that emits the beam;
a first optical switch configured to split the beam into a reference beam and a sensing beam;
a waveguide;
wherein the frequency comb generator is configured to modify the reference beam into a reference comb beam and to modify the sensing beam into a sensing comb beam,
wherein the sensing comb beam interacts with the downhole fluid to form at least a portion of an interacted beam;
a second optical switch that combines the sensing comb beam after interacting with the downhole fluid and the reference comb beam to form the interacted beam having an interferogram,
wherein the downhole fluid is arranged between the first optical switch and the second optical switch,
wherein the sensing comb beam interacts with the downhole fluid at the evanescent field sensing element, and the reference comb beam bypasses the downhole fluid, and
a detector configured to obtain a spectral distribution of at least one of the following:
the beam, the sensing comb beam, the reference comb beam, the interacted beam, or a combination thereof;

detecting, by the detector, spectral distribution of the interacted beam to monitor a composition of the downhole fluid in real-time; and
controlling an actuator with an inflow and injection control device (ICD) based on the composition of the downhole fluid.