Nanofiber spectral analysis

Patent metadata

Field	Value
Publication number	US-10151702-B2
Application number	US-201514588757-A
Country	US
Kind code	B2
Filing date	Jan 2, 2015
Priority date	Aug 21, 2009
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

Apparatus, systems, and methods may operate to transmit energy to a nanofiber sampling coil and/or a nanofiber reference coil. Further activity may include receiving the energy as modified by evanescent interaction with a sampled material located proximate to the sampling coil and/or as modified by propagation through the reference coil, and comparing the energy modified by evanescent interaction with the energy modified by propagation through the reference coil to determine a spectroscopic property of the sampled material. Additional apparatus, systems, and methods, including the use of nanofibers and fluorescence induced by evanescent radiation to conduct spectroscopic analysis, are disclosed.

First claim

What is claimed is:

1. An apparatus, comprising:
a plurality of sampling optical nanofibers, each of the sampling optical nanofibers formed into a sampling optical nanofiber coil having a first sampling end and a second sampling end;
at least one reference nanofiber formed into a reference optical nanofiber coil having a first reference end and a second reference end;
a pressure-tight chamber defined by an inner surface that is completely enclosed by an outer surface, the first and the second sampling ends disposed within the pressure-tight chamber, each of the sampling optical nanofiber coils disposed outside the pressure-tight chamber in a region open to fluid flow to sample the fluid;
an optical energy source to direct optical energy to the first sampling ends and the first reference end, the optical energy source disposed in the pressure-tight chamber; and
a receiver arranged to receive, from each of the second sampling ends, optical energy resulting from the optical energy transmitted to each of the first sampling ends being modified by evanescent interaction with sample material located within an inner diameter of the sampling optical nanofiber coils or outside an outer diameter of the sampling optical nanofiber coils, and to receive, from the second reference end, optical energy resulting from the optical energy transmitted to the first reference end being modified by propagation through the reference coil.

2. The apparatus of claim 1 , wherein the optical energy source comprises:
a plurality of broadband optical sources having substantially orthogonal wave functions.

3. The apparatus of claim 2 , wherein the plurality of broadband optical sources is arranged to direct the optical energy from each one of the broadband optical sources to one of a corresponding plurality of reference optical nanofibers that includes the at least one reference optical nanofiber.

4. The apparatus of claim 1 , wherein the optical energy source comprises a broadband optical energy source, and wherein the receiver comprises:
one of a tunable receiver to resolve a plurality of wavelengths in the optical energy provided by the broadband optical energy source or a plurality of receivers corresponding to a plurality of reception wavelength sensitivities.

5. The apparatus of claim 1 , wherein the optical energy source comprises:
one of a single broadband optical source or a plurality of substantially monochromatic optical sources to provide the optical energy.

6. The apparatus of claim 1 , wherein the optical energy source comprises:
one of a broadband optical source or a substantially monochromatic optical source.

7. The apparatus of claim 1 , wherein the optical energy source comprises:
a frequency tunable, substantially monochromatic optical source.

8. The apparatus of claim 1 , wherein the reference optical nanofiber coil is disposed outside the chamber.

9. The apparatus of claim 1 , wherein at least two of the plurality of sampling optical nanofiber coils have different coil diameters corresponding to different sensitivity wavelengths, and a spacing between loops in the at least two of the plurality of sampling optical nanofiber coils is greater than one evanescent wavelength associated with one of the at least two of the plurality of sampling optical nanofiber coils.

10. The apparatus of claim 1 , wherein the sampling optical nanofiber coils are at least partially coated with a pH-selective compound or an ion-selective compound.

11. A system comprising:
a downhole tool; and
an apparatus attached to the downhole tool, the apparatus including a plurality of sampling optical nanofibers, each of the sampling optical nanofibers formed into a sampling optical nanofiber coil having a first sampling end and a second sampling end;
at least one reference optical nanofiber formed into a reference optical nanofiber coil having a first reference end and a second reference end;
a pressure-tight chamber defined by an inner surface that is completely enclosed by an outer surface, the first and the second sampling ends disposed within the pressure-tight chamber, each of the optical nanofiber sampling coils disposed outside the pressure-tight chamber in a region open to downhole fluid flow to sample the downhole fluid;
an optical energy source arranged to direct optical energy to the first sampling ends and the first reference end, the optical energy source disposed in the pressure-tight chamber; and
a receiver arranged to receive, from each of the second sampling ends, optical energy resulting from the optical energy transmitted to each of the first sampling ends being modified by evanescent interaction with sample material located within an inner diameter of the sampling optical nanofiber coils or outside an outer diameter of the sampling optical nanofiber coils, and to receive, from the second reference end, optical energy resulting from the optical energy transmitted to the first reference end being modified by propagation through the reference optical nanofiber coil.

12. The system of claim 11 , further comprising:
a balancing bridge coupled to one of the sampling optical nanofibers and the at least one reference optical nanofiber.

13. The system of claim 11 , further comprising:
the receiver having a plurality of detectors with specific wavelength response factors, the detectors configured to create a multivariate signal as the receiver output; and
one or more processors configured to compare the electromagnetic energy modified by evanescent interaction with the sampled downhole fluid with the electromagnetic energy modified by propagation through the reference optical nanofiber coil and to provide a regression output based on a calibration input and the receiver output, to determine a spectroscopic property of the sampled downhole fluid.

14. The system of claim 11 , further comprising:
a wavelength discriminator interposed between the second sampling ends and the receiver.

15. The system of claim 11 , wherein the optical energy source comprises:
a plurality of optical energy sources coupled to a multiple-input, single-output multiplexer.

16. The system of claim 11 , further comprising:
a ferromagnetic seal to seal the plurality of sampling optical nanofibers against the inner surface.

17. A method comprising:
immersing a plurality of sampling optical nanofibers in a downhole fluid located outside a pressure-tight chamber in a region in a borehole open to fluid flow, the pressure-tight chamber housing an energy source used to provide optical energy, each of the sampling optical nanofibers formed into a sampling optical nanofiber coil, the sampling optical nanofiber coil being immersed in the downhole fluid to sample the downhole fluid;
transmitting the optical energy to a first sampling end of each sampling optical nanofiber of the plurality of sampling optical nanofibers, each of the sampling optical nanofibers having a second sampling end, the first sampling ends and the second sampling ends disposed in the pressure-tight chamber housing the energy source;
transmitting energy to a first reference end of a reference optical nanofiber formed into a reference optical nanofiber coil having a second reference end;
receiving, from each second sampling end, optical energy resulting from the optical energy transmitted to each first sampling end being modified by evanescent interaction with sample material located within an inner diameter or outside of an outer diameter of the sampling optical nanofiber coils;
receiving, from the second reference end, optical energy resulting f

Assignees

• Halliburton Energy Services Inc

Inventors

• Jones Christopher Michael

Classifications

• E21B47/135

  using light waves, e.g. infrared or ultraviolet waves · CPC title

• Y10S977/954

  Of radiant energy · CPC title

• G01N2201/088

  Using a sensor fibre · CPC title

• G01N21/80

  Indicating pH value · CPC title

• G01N21/648 Primary

  using evanescent coupling or surface plasmon coupling for the excitation of fluorescence · CPC title