Characterizing lubricant oil degradation using fluorescence signals

Patent metadata

Field	Value
Publication number	US-2018348192-A1
Application number	US-201816056020-A
Country	US
Kind code	A1
Filing date	Aug 6, 2018
Priority date	Apr 26, 2016
Publication date	Dec 6, 2018
Grant date	—

Abstract

Methods, systems, and apparatus to diagnose lubrication oil deterioration. In one aspect, a method includes irradiating a lubrication oil sample with a light beam to emit a light-induced fluorescence, detecting and processing the light-induced fluorescence signal to determine a temporal variation of a fluorescence intensity, identifying a steady state of the light-induced fluorescence signal, processing the temporal variation of the fluorescence intensity to determine a lubrication oil parameter, and correlating the oil parameter to a calibration curve to diagnose the lubrication oil deterioration.

First claim

What is claimed is:

1 . A method to diagnose lubrication oil deterioration, the method comprising:
generating a continuous wave collimated light beam; chopping the continuous wave collimated light beam into a plurality of step light beams, each step light beam having a constant intensity for a particular time interval; irradiating a lubrication oil sample with the plurality of step light beams such that a light-induced fluorescence is emitted from the lubrication oil sample in response to irradiation by each step light beam; detecting a light-induced fluorescence signal from the lubrication oil sample; determining a lubrication oil parameter from the light-induced fluorescence signal, wherein the lubrication oil parameter is associated to at least one of an oil viscosity, a damping ratio of the fluorescence signal, and an undamped natural frequency of the fluorescence signal; and determining an amount of lubrication oil deterioration by correlating the lubrication oil parameter to a calibration curve.

2 . The method of claim 1 , wherein determining the lubrication oil parameter comprises determining a temporal variation of a fluorescence intensity from the light-induced fluorescence-signal.

3 . The method of claim 2 , wherein determining the lubrication oil parameter comprises determining a steady-state of the light-induced fluorescence-signal from the temporal variation of the fluorescence intensity.

4 . The method of claim 3 , wherein determining the lubrication oil parameter comprises determining the lubrication oil parameter from the steady-state of the light-induced fluorescence-signal.

5 . The method of claim 1 , further comprising collecting the lubrication oil sample from an industrial equipment.

6 . The method of claim 1 , further comprising guiding the light beam at an acute angle on a front surface of a container holding the lubrication oil sample.

7 . The method of claim 1 , further comprising filtering the light-induced fluorescence signal.

8 . The method of claim 1 , further comprising capturing the light-induced fluorescence signal by a fast photodiode.

9 . The method of claim 2 , wherein the fluorescence intensity is represented as a second order dynamic system corresponding to one of an over-damped oscillator with a damping factor larger than 1 or an under-damped oscillator with a damping ratio smaller than 1.

10 . The method of claim 1 , further comprising:
comparing the oil parameter to previously measured oil parameter to determine an oil deterioration rate; and determining an estimate of a useful remaining lifetime of the industrial equipment associated to the lubrication oil sample based on the oil deterioration rate, wherein the industrial equipment is in use in a hydrocarbon-producing well during determining the estimate of the useful remaining lifetime of the industrial equipment.

11 . The method of claim 10 , wherein the industrial equipment is a submersible pump configured to pump fluid uphole from the hydrocarbon-producing well and wherein the submersible pump is disposed within the hydrocarbon-producing well.

12 . The method of claim 1 , wherein the light beam is generated by a laser source.

13 . A system, comprising:
a light beam generator configured to generate a continuous wave collimated light beam; a chopper configured to chop the continuous wave collimated light beam into a plurality of step laser beams, each step laser beam having a constant intensity for a particular time interval; a container comprising a lubrication oil sample; an optical equipment configured to guide each of the plurality of step laser beams to a face of the container; a fast photodiode configured to detect light-induced fluorescence signal from the lubrication oil sample in response to irradiation by each step light beam; and a hardware processor interoperably coupled with a memory and configured to:
determine a lubrication oil parameter from the light-induced fluorescence signal, wherein the lubrication oil parameter is associated to at least one of an oil viscosity, a damping ratio of the fluorescence signal, and an undamped natural frequency of the fluorescence signal; and
determine an amount of lubrication oil deterioration by correlating the lubrication oil parameter to a calibration curve.

Assignees

• Saudi Arabian Oil Co

Inventors

• Hegazi Ezzat
• Cunningham Vincent
• Nour Maha

Classifications

• G01N33/2888 Primary

  Lubricating oil characteristics, e.g. deterioration (lubricating properties G01N33/30) · CPC title

• G01N2021/6482

  Sample cells, cuvettes · CPC title

• G01N21/6408

  with measurement of decay time, time resolved fluorescence · CPC title

• G01N2201/129

  Using chemometrical methods · CPC title

• G01N21/643

  non-biological material · CPC title