In-situ monitoring of chemical fingerprints in oilfield applications
A system for monitoring a composition includes: an electromagnetic source that emits a beam; one or more evanescent field sensing element inside a tubular structure, arranged in series along a flow direction of the composition, and configured to be in direct contact with the composition; a waveguide that directs at least a portion of the beam to the evanescent field sensing element as an incident beam; and a detector configured to obtain a spectral distribution of the fingerprint beam. The evanescent field sensing element provides partial or total internal reflection of the incident beam at an interface between the evanescent field sensing element and the composition, and the incident beam interacts with the composition to form a fingerprint beam.
1. A system for monitoring a composition, the system comprising:
an electromagnetic source that emits a beam;
one or more evanescent field sensing element inside a tubular structure, arranged in series along a flow direction of the composition generating turbulence, and configured to be in direct contact with the composition;
a waveguide that directs at least a portion of the beam to the evanescent field sensing element as an incident beam;
wherein
the evanescent field sensing element provides partial or total internal reflection of the incident beam at an interface between the evanescent field sensing element and the composition, and
the incident beam interacts with the composition to form a fingerprint beam;
a coupler that splits the beam, such that at least a portion of the beam serves as a reference beam without passing through the evanescent field sensing element;
at least one frequency comb generator that modifies both the reference beam and the incident beam with optical frequency comb (OFC); and
a detector configured to obtain a spectral distribution of the fingerprint beam.
2. The system according to claim 1 , wherein the evanescent field sensing element has a shape selected from the group consisting of point, line, prism, cylinder, tube, ring, helix, and combinations thereof.
3. The system according to claim 1 , further comprising a second coupler that recombines the fingerprint beam and the reference beam to form the interacted beam having an interferogram.
4. The system according to claim 1 , wherein the detector is a Fourier transform spectrometer or at least one photodiode.
5. The system according to claim 1 , wherein the electromagnetic source is an array of lasers or a wide-band light source that emit the beam having a range of frequency.
6. The system according to claim 1 , wherein the evanescent field sensing element is at least one of the following: a crystal with or partial or total internal reflection, an optical fiber, a waveguide, a meta-surface, and a meta-material.
7. The system according to claim 1 , wherein a surface of the evanescent field sensing element further comprises a modification layer of at least one of the following: a protective layer, a sensitivity enhancing layer, and a self-cleaning layer.
8. The system according to claim 1 , wherein the evanescent field sensing element is modified with meta-materials or meta-surfaces in forms of a 1-dimensional or 2-dimensional array of microstructures of particular shape.
9. A method for monitoring a composition, the method comprising:
placing one or more evanescent field sensing element in series along a flow direction of the composition;
contacting the evanescent field sensing element with the composition such that, due to the arrangement of the evanescent field sensing element in series along the flow direction, turbulence in the composition is generated;
generating a beam from an electromagnetic source;
splitting the beam into a reference beam and an incident beam;
modifying the reference beam and the incident beam with at least one frequency comb generator;
directing the incident beam to the evanescent field sensing element;
generating an evanescent field at an interface between the evanescent field sensing element and the composition, where the incident beam interacts with the composition to form a fingerprint beam;
recombining the reference beam and the fingerprint beam; and
detecting spectral distribution of the fingerprint beam using a Fourier transform spectrometer or at least one photodiode to monitor the composition in real-time; and
transmitting the spectral distribution to a control unit.
10. The method according to claim 9 , further comprising:
prior to placing the evanescent field sensing element, modifying the evanescent field sensing element with at least one of the following: a protective layer, a sensitivity enhancing layer, and a self-cleaning layer.
11. The method according to claim 9 , wherein the evanescent field sensing element have a shape selected from the group consisting of point, line, prism, cylinder, tube, ring, helix, and combinations thereof.
12. The method according to claim 9 , wherein the evanescent field sensing element is modified with meta-materials or meta-surfaces in forms of a 1-dimensional or 2-dimensional array of microstructures of particular shape.