Patent US3689857A successfully refreshed from Google Patents.
Patent US5266800A successfully refreshed from Google Patents.
US5266800A
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US
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Method of distinguishing between crude oils
Assignee: Schlumberger Technology Corp
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Filing: 1992-10-01
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Granted: 1993-11-30
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Expires: 2012-10-01
Abstract
Abstract Methods for distinguishing among oil samples, and more particularly between a fluid containing oil base mud and formation oil samples are described. The methods all rely on the discovery that the optical absorption spectrum of all crude oils in the visible and near infrared spectra can be described according to the equation OD=ae Eb , where (OD) is a measured optical density, (b) is a value between 0.37 and 0.55 chosen according to the wavenumber (E) and can be chosen as a constant equal to 4.6×10 -4 cm, and (a) is an unknown which classifies the crude oil. By making measurements and solving for (a), a crude oil can be classified. In a flow stream which has a changing oil content, such as may be obtained by a borehole tool which obtains fluid samples from the formation, by monitoring the unknown (a), a determination may be made as to when a formation oil is being obtained as opposed to a mud filtrate.
Inventors
- 👤 Oliver C. Mullins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:41
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/359; G01N21/3577; G01N33/00; G01N33/26; G01N33/28; G01N33/2823
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
125 words
A method for classifying an oil sample, comprising: a) making an optical density measurement (OD) of said oil sample by detecting photons of at least one energy defined by wavenumbers (E) whose wavelenqths are between 200 and 2500 nm, wherein said at least one energy is chosen such that the optical absorption of said photons at said at least one energy is dominated by electronic absorption by said oil sample; b) using said optical density measurement OD, solving an equation relating said optical density measurement OD to a dominant term ae Eb for an unknown (a), where (a) classifies the oil type, (E) is the wavenumber which is the inverse of the wavelength, and where (b) is an exponential decay value for said oil sample.
Claim 2
Independent Claim
125 words
A method for classifying an oil sample, comprising: a) making an optical density measurement (OD) of said oil sample by detecting photons of at least one energy defined by wavenumbers (E) whose wavelenqths are between 200 and 2500 nm, wherein said at least one energy is chosen such that the optical absorption of said photons at said at least one energy is dominated by electronic absorption by said oil sample; b) using said optical density measurement OD, solving an equation relating said optical density measurement OD to a dominant term ae Eb for an unknown (a), where (a) classifies the oil type, (E) is the wavenumber which is the inverse of the wavelength, and where (b) is an exponential decay value for said oil sample.
Claim 3
Dependent Claim
23 words
A method according to claim 1, wherein: b is a value between 0.37×10 -4 cm and 0.55×10 -4 cm chosen according to E.
Claim 4
Dependent Claim
15 words
A method according to claim 1, wherein: b is a constant regardless of E value.
Claim 5
Dependent Claim
52 words
A method according to claim 1, wherein: said equation relating said optical density measurement OD to a dominant term ae Eb is substantially of the form OD=ae.sup.Eb +S where S is a term relating to scattering of photons, and optical density measurements are made for photons of at least two different energies.
Claim 6
Dependent Claim
23 words
A method according to claim 4, wherein: said at least two different energies include energies defined by wavelengths between 200 and 2500 nm.
Claim 7
Dependent Claim
12 words
A method according to claim 4, wherein: S is taken as zero.
Claim 8
Independent Claim
123 words
A method for monitoring a fluid flow stream for a change over time of oils which constitute of a portion of said fluid flow stream, said method comprising: a) making optical density measurements (OD) of said fluid flow stream over time by detecting photons having an energy with wavelengths in at least the visible or near infrared spectrum; b) determining a change in an oil classification variable (a) over time by solving for said oil classification variable (a) in an equation relating said optical density measurements OD to a dominant term ae Eb , where E is the inverse of the wavelength or a wavenumber corresponding to said wavelength, and b is an exponential decay value for oils in said fluid flow stream.
Claim 9
Independent Claim
123 words
A method for monitoring a fluid flow stream for a change over time of oils which constitute of a portion of said fluid flow stream, said method comprising: a) making optical density measurements (OD) of said fluid flow stream over time by detecting photons having an energy with wavelengths in at least the visible or near infrared spectrum; b) determining a change in an oil classification variable (a) over time by solving for said oil classification variable (a) in an equation relating said optical density measurements OD to a dominant term ae Eb , where E is the inverse of the wavelength or a wavenumber corresponding to said wavelength, and b is an exponential decay value for oils in said fluid flow stream.
Claim 10
Dependent Claim
23 words
A method according to claim 7, wherein: b is a value between 0.37×10 -4 cm and 0.55×10 -4 cm chosen according to E.
Claim 11
Dependent Claim
15 words
A method according to claim 7, wherein: b is a constant regardless of E value.
Claim 12
Dependent Claim
61 words
A method according to claim 7, wherein: said equation relating said optical density measurements OD to a dominant term ae Eb is substantially of the form OD=ae.sup.Eb +S where S is a term relating to scattering of photons, and said optical density measurements are made for photons having at least two different energies defined by wavelengths between 200 and 2500 nm.
Claim 13
Dependent Claim
12 words
A method according to claim 10, wherein: S is taken as zero.
Claim 14
Dependent Claim
157 words
An in situ method for monitoring fluids obtained over time by a borehole tool in a borehole in order to determine when said borehole tool is obtaining primarily formation fluids as opposed to an oil based mud filtrate, said method comprising: a) making a plurality of optical density measurements (OD) with said borehole tool in said borehole of the obtained fluid over time by detecting photons of energy with wavelengths located in the visible or near infrared spectra; b) repeatedly solving an equation relating said optical density measurements OD to a dominant term ae Eb , for (a), with said plurality of optical density measurements (OD) and said energy as inputs to said equation, where (a) is an oil classification variable, E is the inverse of the wavelength or a wavenumber corresponding to said wavelength, and where b is an exponential decay value for oils in the monitored fluids; and c) monitoring (a) for changes in value.
Claim 15
Dependent Claim
157 words
An in situ method for monitoring fluids obtained over time by a borehole tool in a borehole in order to determine when said borehole tool is obtaining primarily formation fluids as opposed to an oil based mud filtrate, said method comprising: a) making a plurality of optical density measurements (OD) with said borehole tool in said borehole of the obtained fluid over time by detecting photons of energy with wavelengths located in the visible or near infrared spectra; b) repeatedly solving an equation relating said optical density measurements OD to a dominant term ae Eb , for (a), with said plurality of optical density measurements (OD) and said energy as inputs to said equation, where (a) is an oil classification variable, E is the inverse of the wavelength or a wavenumber corresponding to said wavelength, and where b is an exponential decay value for oils in the monitored fluids; and c) monitoring (a) for changes in value.
Claim 16
Dependent Claim
60 words
An in situ method according to claim 12, wherein: said step of monitoring comprises monitoring (a) for changes in value over a first time period and for substantial stability in value over a second time period after said first time period, whereby a determination is made that primarily formation fluids are being obtained in at least said second time period.
Claim 17
Dependent Claim
26 words
An in situ method according to claim 12, wherein: b is a value between 0.37×10 -4 cm and 0.55 ×10 -4 cm chosen according to E.
Claim 18
Dependent Claim
15 words
A method according to claim 12, wherein: b is a constant regardless of E value.
Claim 19
Dependent Claim
61 words
A method according to claim 12, wherein: said equation relating said optical density measurements OD to a dominant term ae Eb is substantially of the form OD=ae.sup.Eb +S where S is a term relating to scattering of photons, and said optical density measurements are made for photons having at least two different energies defined by wavelengths between 200 and 2500 nm.
Claim 20
Dependent Claim
23 words
A method according to claim 13, wherein: b is a value between 0.37×10 -4 cm and 0.55×10 -4 cm chosen according to E.
Claim 21
Dependent Claim
15 words
A method according to claim 13, wherein: b is a constant regardless of E value.
Claim 22
Dependent Claim
61 words
A method according to claim 13, wherein: said equation relating said optical density measurements OD to a dominant term ae Eb is substantially of the form Od=ae.sup.Eb +S where S is a term relating to scattering of photons, and said optical density measurements are made for photons having at least two different energies defined by wavelengths between 200 and 2500 nm.
Claim 23
Dependent Claim
12 words
A method according to claim 19, wherein: S is taken as zero.
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