US3740641A
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Process for determining hydrocarbon maturity using electron spin resonance
Assignee: ConocoPhillips Co
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Filing: 1971-08-25
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Granted: 1973-06-19
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Expires: 1991-08-25
Abstract
Abstract A process for predicting the presence and maturity of hydrocarbon material in a subterranean situs by initially treating a number of rock samples derived from an exploratory well or surface outcrops to remove certain materials therefrom, including carbonates and layered silicates. The samples, as thus prepared, are then subjected to observation of the paramagnetic resonance (electron spin resonance) properties of the kerogen entrapped in the samples, and from these properties, the maximum thermal histories of the samples are evaluated, and a maximal geothermal gradient for the formation is derived. The maximal geothermal gradient is extrapolated to a depth of interest to predict the type of hydrocarbon production, if any, which may be reasonably contemplated from that depth in the formation.
Inventors
- 👤 P Hwang
- 👤 W Pusey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:07
CPC Classifications
G; G01; G01V; G01V3/00; G01N; G01N33/00; G01N33/24; G01N33/241; G01V3/14; Y; Y10; Y10T; Y10T436/00; Y10T436/24
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
31 words
A process as defined in claim 1 wherein said rock sample treatment comprises: contacting the rock samples with a concentrated mineral acid; and then contacting the rock samples with hydrofluoric acid.
Claim 2
Dependent Claim
27 words
A process as defined in claim 1 wherein the electron spin resonance property measured is the spectral line position of the sample in the established magnetic field.
Claim 3
Dependent Claim
22 words
A process as defined in claim 1 wherein the electron spin resonance property measured is the spectral line width of the sample.
Claim 4
Dependent Claim
28 words
A process as defined in claim 1 wherein the electron spin resonance property measured is the spin concentration in spins per gram of organic carbon in the sample.
Claim 5
Dependent Claim
70 words
A process as defined in claim 1 wherein said rock samples are removed from a plurality of vertically spaced locations in an upper portion of said subterranean situs, and a graphical plot of the depth of said locations vs. the measured electronic spin resonance properties of said samples is extrapolated to other depths in the lower portion of said situs to indicate the maximum thermal history at said other depths.
Claim 6
Dependent Claim
27 words
A process as defined in claim 1 wherein said removed samples are of a size before treatment to contain at least 1 weight percent kerogen following treatment.
Claim 7
Dependent Claim
126 words
A process as defined in claim 2 wherein said sample treatment with the said acids further comprises: initially crushing the samples to a particle size not exceeding 60 mesh, contacting the crushed sample with from about 10 ml. to about 100 ml. of 10 normal hydrochloric acid for each 4 to 8 grams of sample to solubilize the carbonate compounds; washing the sample with water; contacting the sample with from about 10 ml. to about 50 ml. of 52 weight percent hydrofluoric acid until visible reaction terminates; washing the sample with water; contacting the sample with from about 10 ml. to about 50 ml. of 70 weight percent hydrofluoric acid to solubilize certain silicate compounds; and then washing the sample with water and volatile organic solvent.
Claim 8
Independent Claim
140 words
A method for predicting the character of hydrocarbons which may be found at a subterranean situs comprising: taking a series of rock samples from vertically spaced locations between the surface and the situs; acid treating each sample to concentrate kerogenous material occurring naturally therein and remove a substantial portion of any contained carbonates and silicates therefrom; observing a plurality of the thermal history-related paramagnetic resonance properties of each sample; using said properties to determine the maximum thermal history of the location from which the respective sample was taken; deriving a geothermal vertical gradient from said series of maximum thermal histories; extrapolating the geothermal vertical gradient to the depth of said situs to determine the maximum thermal history of the situs; and predicting the character of hydrocarbons at said situs on the basis of the maximum thermal history at the situs.
Claim 9
Dependent Claim
46 words
The method defined in claim 9 wherein said acid treating comprises: pulverizing the respective sample; treating the respective sample with hydrochloric acid; washing the sample substantially free of hydrochloric acid; treating the respective sample with hydrofluoric acid; and then washing the sample free of hydrofluoric acid.
Claim 10
Dependent Claim
45 words
The method defined in claim 9 wherein the paramagnetic resonance properties observed are (a) the spectral line position of the sample in the magnetic field, (b) the spectral line width, and (c) the spin concentration of the sample in spins per gram of organic carbon.
Claim 11
Dependent Claim
38 words
The method defined in claim 10 wherein the size of each of said samples when subjected to acid treatment is such that each sample will contain at least 1 weight percent kerogen upon completion of said acid treatment.
Claim 12
Independent Claim
116 words
A method of determining the highest temperature to which a thermally uncharacterized subterranean rock has been heated at any time during its geologic history when petroleum forming organic matter may have been in the vicinity of the rock comprising: measuring the paramagnetic resonance properties of the kerogen in subterranean rocks presently at such highest temperatures; correlating said measured paramagnetic resonance properties to such highest temperature values; repeating said measurement and correlation with a sufficient number of additional subterranean rocks to establish the repeatability and universality of said correlation; and then measuring the paramagnetic properties of said thermally uncharacterized rock to determine therefrom through said correlation, said highest temperature to which said uncharacterized rock has been heated.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |