PHASE FRACTION MEASUREMENT USING CONTINUOUSLY ADJUSTED LIGHT SOURCE

• US 20170370828A1
• Filed: 06/28/2016
• Published: 12/28/2017
• Est. Priority Date: 06/28/2016
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Arifin, Arifin, Xie, Cheng-Gang
• Granted Patent: US 10,054,537 B2
• Time in Patent Office: Days
• CPC Class Codes: G01N 15/0205 by optical means
• CPC Class Codes: G01N 15/06 Investigating concentration of particle suspensions by weighing G01N5/00; investigating sedimentation of particle suspensions G01N15/04; investigating individual particles G01N15/10
• CPC Class Codes: G01N 15/075 by optical means
• CPC Class Codes: G01N 2015/0011 in liquids, e.g. bubbles
• CPC Class Codes: G01N 2015/0053 in liquids, e.g. trouble
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 21/532 with measurement of scattering and transmission
• CPC Class Codes: G01N 2201/06113 Coherent sources; lasers
• CPC Class Codes: G01N 2201/0633 Directed, collimated illumination
• CPC Class Codes: G01N 2201/0694 Microprocessor controlled supply
• CPC Class Codes: G01N 2201/12 Circuits of general importance; Signal processing
• CPC Class Codes: G01N 2201/1241 Multirange
• CPC Class Codes: G01P 5/26 by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave

Abstract

An apparatus includes a pipe through which a multiphase fluid flows, with a transparent window structure formed in the pipe. A collimated light source emits light through the transparent window structure into the pipe having a wavelength at which a component of a desired phase of the multiphase fluid is absorptive. A photodetector is positioned such that the emitted light passes through the multiphase fluid in the pipe to impinge upon the photodetector. The photodetector has an actual dynamic range for collimated light detection. Processing circuitry is configured to continuously adjust a power of the collimated light source dependent upon an output level of the photodetector so as to cause measurement of the emitted light over an effective dynamic range greater than the actual dynamic range, and determine a property of the multiphase fluid as a function of the power of the collimated light source.

Claims

1. An apparatus comprising:

a pipe through which a multiphase fluid flows;

a transparent window structure formed in the pipe;

a collimated light source configured to emit light through the transparent window structure and into the pipe, the emitted light having a wavelength at which a component of a desired phase of the multiphase fluid is absorptive;

a photodetector positioned such that the emitted light passes through the multiphase fluid in the pipe and out through the transparent window structure to impinge upon the photodetector, wherein the photodetector has an actual dynamic range for collimated light detection;

processing circuitry coupled to the collimated light source and photodetector, the processing circuitry configured to;

continuously adjust a power of the collimated light source dependent upon an output level of the photodetector so as to cause measurement of the emitted light by the photodetector over an effective dynamic range greater than the actual dynamic range;

determine at least one property of the multiphase fluid as a function of the power of the collimated light source.

2. The apparatus of claim 1, wherein the processing circuitry continuously adjusts the power of the collimated light source dependent upon the output of the photodetector by continuously adjusting the power of the collimated light source such that the output level of the photodetector remains constant.

3. The apparatus of claim 1, wherein the emitted light passes through substantially an entire cross sectional area of the multiphase fluid in the structure.

4. The apparatus of claim 1, further comprising at least one lens associated with the collimated light source for shaping the emitted light into a ribbon shape.

5. The apparatus of claim 1, wherein the collimated light source comprises a first collimated light source having a first wavelength at which a component of a first phase of the multiphase fluid is absorptive;

and further comprising a second collimated light source having a second wavelength at which a component of a second phase of the multiphase fluid is absorptive, and a third collimated light source having a third wavelength at which components of the first and second phases of the multiphase fluid are not absorptive.

6. The apparatus of claim 5, wherein the first phase of the multiphase fluid comprises oil;

wherein the second phase of the multiphase fluid comprises water;

wherein a third phase of the multiphase fluid comprises gas; and

wherein the at least one property of the multiphase fluid comprises phase fractions of gas, oil, and water.

7. The apparatus of claim 6, wherein the first wavelength is substantially at a hydrocarbon peak absorption band;

wherein the second wavelength is at a water absorption band where water is more absorptive of light than oil; and

wherein the third wavelength is at a band where neither water nor oil is substantially absorptive.

8. The apparatus of claim 1, wherein the processing circuitry is configured to differentiate between sand, and bubbles or droplets.

9. The apparatus of claim 5, wherein a fourth phase of the multiphase fluid comprises a solid phase;

further comprising a fourth collimated light source having a fourth wavelength at which components of the solid phases of the multiphase fluid is absorptive.

10. The apparatus of claim 5, wherein the processing circuitry is configured to pulse the first, second, and third collimated light sources in a pattern such that but one of the first, second, and third collimated light sources is emitting light at a time.

11. The apparatus of claim 5, wherein the processing circuitry is configured to pulse the first, second, and third collimated light sources simultaneously and at different pulsing frequencies from one another, and is configured to perform phase-sensitive detection simultaneously for the first, second, and third collimated light sources.

12. The apparatus of claim 11, wherein the processing circuitry is configured to discriminate between components of the emitted light impinging upon the photodetector that were emitted by the first collimated light source, components of the emitted light impinging upon the photodetector that were emitted by the second collimated light source, and components of the emitted light impinging upon the photodetector that were emitted by the third collimated light source, using phase sensitive detection.

13. The apparatus of claim 5, wherein:

the first collimated light source comprises a first laser light source configured to emit laser light along a path that does not include the transparent window structure, and a first mirror configured to reflect the laser light from the first laser light source along a path that includes the transparent window structure;

the second collimated light source comprises a second laser light source configured to emit laser light along a path that does not include the transparent window structure, and a second mirror configured to reflect the laser light from the second laser light source along a path that includes the transparent window structure; and

the third collimated light source comprises a third laser light source configured to emit laser light along a path that does not include the transparent window structure, and a third mirror configured to reflect the laser light from the third laser light source along a path that includes the transparent window structure;

and further comprising;

at least one lens to focus the reflected laser light from the first, second, and third laser light sources.

14. The apparatus of claim 1, further comprising an additional photodetector positioned such that emitted light that scatters off the multiphase fluid and out through the transparent window structure impinges upon the additional photodetector;

wherein the processing circuit is configured to measure the scattered emitted light; and

wherein the processing circuitry also determines the at least one property of the multiphase fluid as a function of the measured scattered emitted light.

15. The apparatus of claim 14, wherein the at least one property of the multiphase fluid comprises a phase fraction of solids in the multiphase fluid.

16. A method of determining at least one property of a multiphase fluid comprising:

emitting, into the multiphase fluid, collimated light from a collimated light source, the emitted collimated light having a wavelength at which a component of a desired phase of the multiphase fluid is absorptive;

detecting light passing through the multiphase fluid impinging upon a photodetector, the photodetector having an actual dynamic range for collimated light detection;

continuously adjusting a power of the collimated light source dependent upon an output level of the photodetector so as to cause measurement of the emitted collimated light by the photodetector over an effective dynamic range greater than the actual dynamic range; and

determining at least one property of the multiphase fluid as a function of the power of the collimated light source.

17. The method of claim 16, wherein continuously adjusting the power of the collimated light source comprises continuously adjusting the power of the collimated light source such that the output level of the photodetector remains constant.

18. The method of claim 16, wherein adjustment of the power of the collimated light source over time yields a pattern of output power values;

and wherein determining the at least one property of the multiphase fluid as a function of the power of the collimated light source comprises determining presence of sand grains as a function of the pattern of output power values.

19. The method of claim 18, wherein presence of the sand grains is determined either as a function of the pattern of output power values by performing a Fourier transform on the pattern of output power values and determining the presence of the sand grains by matching a frequency pattern output by the Fourier transform to a known sand grain frequency pattern, or as a function of the pattern of output power values by correlating the pattern of output power values to a known sand grain output power value pattern.

20. The method of claim 18, further comprising determining at least one of sizes of the sand grains and a number of the sand grains as a function of the pattern of output power values.