Baker Hughes Corporation

Arnold Walkow

Rocco DiFoggio

Paul Allan Bergren

Louis Perez

Peter W Reittinger

The present invention provides a simple, robust, and versatile high-resolution spectrometer that is suitable for downhole use. The present invention provides a method and apparatus incorporating a spinning, oscillating or stepping optical interference filter to change the angle at which light passes through the filters after passing through a sample under analysis downhole. As each filter is tilted, the color or wavelength of light passed by the filter changes. Black plates are placed between the filters to isolate each filter's photodiode. The spectrometer of the present invention is suitable for use with a wire line formation tester, such as the Baker Atlas Reservation Characterization Instrument to provide supplemental analysis and monitoring of sample clean up. The present invention is also suitable for deployment in a monitoring while drilling environment. The present invention provides a high resolution spectometer which enables quantification of a crude oil's percentage of aromatics, olefins, and saturates to estimate a sample's gas oil ratio (GOR). Gases such as COare also detectable. The percentage of oil-based mud filtrate contamination in a crude oil sample can be estimated with the present invention by using a suitable training set and chemometrics, a neural network, or other type of correlation method.

Method and apparatus for a high resolution downhole spectrometer

The invention comprises an apparatus and method for simple fluorescence spectrometry in a down hole environment. The apparatus and method utilization of two UV light bulbs and an optically clear UV coupler and a fluid containment system. The optically clear UV coupler and fluid containment system are made of sapphire. The apparatus is attached in a manner that enables light transmitted from a light source on the far side of the fluid containment system to pass through a pathway in a plate holding the UV bulbs. UV light illuminates the fluid, which in turn fluoresces light. The fluoresced light is transmitted back towards the UV bulb mount and through the pathway towards an optical spectrum analyzer.

Method and apparatus for a downhole fluorescence spectrometer

The present invention provides an apparatus and method for randomly distributing a number of fibers associated with a spectral channel over an area of an input optics head input window for sensing optical input. The head comprises a plurality of optical channels each channels having a plurality of fibers spread out and intermingled across the input optics head. Thus, a particle or gas bubble passing in front of the input optics head would temporarily affect all channels but only to a small degree since only a portion of fibers for a particular channel would be affected by the temporary passage of the bubble or particle passing in front of a particular region of the optics head input window.

Fiber optics head utilizing randomized fibers per sensor

The present invention provides a downhole method and apparatus using a flexural mechanical resonator, for example, a tuning fork to provide real-time direct measurements and estimates of the viscosity, density and dielectric constant of formation fluid or filtrate in a hydrocarbon producing well. The present invention additionally provides a method and apparatus for monitoring cleanup from a leveling off of viscosity or density over time, measuring or estimating bubble point for formation fluid, measuring or estimating dew point for formation fluid, and determining the onset of asphaltene precipitation. The present invention also provides for intercalibration of plural pressure gauges used to determine a pressure differential downhole. A hard or inorganic coating is placed on the flexural mechanical resonator (such as a tuning fork) to reduce the effects of abrasion from sand particles suspended in the flowing fluid in which the flexural mechanical resonator is immersed.

Method and apparatus for downhole fluid characterization using flexural mechanical resonators

The invention comprises an apparatus and method for simple fluorescence spectrometry in a downhole environment using a UV light source and UV fluorescence to determine a parameter of interest for a sample downhole. The UV light source illuminates the fluid, which in turn fluoresces light. The fluoresced light is transmitted back towards the UV light source and through the pathway towards an optical spectrum analyzer. API gravity is determined by correlation the wavelength of peak fluorescence and brightness of fluorescent emission of the sample. Asphaltene precipitation pressure is determined by monitoring the blue green content ratio for a sample under going depressurization.

The invention relates to refractometry and attenuated reflectance spectrometry in a wellbore environment. Specifically, it pertains to a robust apparatus and method for measuring refractive index of fluids along a continuum (rather than in steps), and for measuring attenuated reflectance spectra, and for interpreting the measurements made with this apparatus to determine a variety of formation fluid parameters. The present invention provides a method and apparatus to distinguish between gas and liquid based on the much lower index of refraction of gas. It can also be used to monitor fluid sample clean up over time. The refractive index of a wellbore fluid is determined from the fraction, R, of light reflected off the interface between a transparent window that has a known refractive index and this fluid. Preferably, the refractive index is measured at some wavelength of light for which the fluid is not highly attenuating but is optimally attenuating. The adjacent transmission spectrometer can be used to correct the refractive index measurement for attenuation at those wavelengths, which it monitors. Also, this reflection-based refractometer design can be used as an attenuated reflectance spectrometer at highly attenuating wavelengths.

Method and apparatus for a downhole refractometer and attenuated reflectance spectrometer

The present invention provides a downhole method and apparatus using a flexural mechanical resonator, for example, a tuning fork to provide real-time direct measurements and estimates of the viscosity, density and dielectric constant of formation fluid or filtrate in a hydrocarbon producing well. The present invention additionally provides a method and apparatus for monitoring cleanup from a leveling off of viscosity or density over time, measuring or estimating bubble point for formation fluid, measuring or estimating dew point for formation fluid, and determining the onset of asphaltene precipitation. The present invention also provides for intercalibration of plural pressure gauges used to determine a pressure differential downhole.

The invention comprises a method of adapting derivative spectrometry for use in a downhole environment and addresses problems that are inherent in this environment. Such problems include, but are not limited to, elevated temperatures and scattering from particles residing within dirty fluid samples. The invention improves the resolution by measuring the first derivative of the spectrum. The derivative spectrometer of this invention operates by vibrating a linear variable interference filter back and forth along the plane of the filter or by oscillating a circular variable filter about some angle.

Method and apparatus for a derivative spectrometer

A rigid redundant light source for obtaining down hole near infrared data in a NIR data acquisition instrument is provided having a plurality of lamps positioned in close proximity and symmetrically about a common optical axis. A lens system for capturing and collimating the light is provided. The structure is arranged and dimensioned so that a single collimating lens can be used for a plurality of light sources. A switch and sensor is provided for turning on an alternate light source when a first light source burns out. A filter is rotated 90 degrees with respect to the light sources to minimized off axis error when switching between light sources.

Method and apparatus for a rigid backup light source for down-hole spectral analysis

The invention relates to refractometry and attenuated reflectance spectrometry in a wellbore environment. Specifically, it pertains to a robust apparatus and method for measuring refractive index of fluids along a continuum (rather than in steps), and for measuring attenuated reflectance spectra, and for interpreting the measurements made with this apparatus to determine a variety of formation fluid parameters. The present invention provides a method and apparatus to distinguish between gas and liquid based on the much lower index of refraction of gas. It can also be used to monitor fluid sample clean up over time. The refractive index of a wellbore fluid is determined from the fraction, R, of light reflected off the interface between a transparent window that has a known refractive index and this fluid. Preferably, the refractive index is measured at some wavelength of light for which the fluid is not highly attenuating. However, the adjacent transmission spectrometer can be used to correct the refractive index measurement for attenuation at those wavelengths, which it monitors. Also, this reflection-based refractometer design can be used as an attenuated reflectance spectrometer at highly attenuating wavelengths.

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Houston, TX, United States of America

Arnold Walkow