US4933913A
Expired / Lapsed
US
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Method of seismic surveying for resolving the effects of formation anisotropy in shear wave reflection seismic data
Assignee: BP Corp North America Inc
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Filing: 1988-07-29
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Granted: 1990-06-12
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Expires: 2008-07-29
Abstract
Abstract A novel method of seismic exploration has been developed to resolve confusing and distorted shear wave reflection seismic data which can be obtained in areas having anisotropic formations. In particular, the present method of shear wave seismic exploration comprises imparting first shear wave seismic energy into the earth at selected points with a first source having a first polarization with respect to the line of survey, and recording first signals representative of the earth's response with first geophones having a first polarization with respect to the line of survey. Also, second shear wave energy is imparted into the earth at selected points along the line of survey, with a second shear wave source having a second polarization with respect to the line of survey, and recording second signals representative of the earth's response with second geophones having a second polarization with respect to the line of survey. With a measure of the angle between the survey line and a principal axis of an underlying azimuthally anisotropic formation, the first and second signals are inverted to obtain principal component signals in whcih the confusing and distorted shear wave reflection seismic data resulting from anisotropic formations can be ameliorated.
Inventors
- 👤 Leon A. Thomsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:17
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/28; G01V1/284; G01V1/003; G01V2210/00; G01V2210/60; G01V2210/62; G01V2210/626
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
112 words
A method of seismic exploration, comprising the steps of: (a) imparting seismic energy into the earth and generating shear waves having a polarization oblique to the unique axis of an anisotropic subterranean formation; (b) recording first and second signals representative of the earth's response to the generated shear waves with geophones having first and second polarizations with respect to the unique axis of the anisotropic subterranean formation; and (c) processing the first and second signals with a measure of the angular relation of their respective geophone polarizations with the unique axis of the anisotropic formation so as to ameliorate the effects of shear wave birefringence on the first and second recorded signals.
Claim 2
Independent Claim
112 words
A method of seismic exploration, comprising the steps of: (a) imparting seismic energy into the earth and generating shear waves having a polarization oblique to the unique axis of an anisotropic subterranean formation; (b) recording first and second signals representative of the earth's response to the generated shear waves with geophones having first and second polarizations with respect to the unique axis of the anisotropic subterranean formation; and (c) processing the first and second signals with a measure of the angular relation of their respective geophone polarizations with the unique axis of the anisotropic formation so as to ameliorate the effects of shear wave birefringence on the first and second recorded signals.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the first and second polarizations of the geophones are orthogonal.
Claim 4
Dependent Claim
21 words
The method of claim 1 wherein the generated shear waves have an SH polarization with respect to a line of survey.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein the generated shear waves have an SV polarization with respect to a line of survey.
Claim 6
Dependent Claim
29 words
The method of claim 1 wherein the first geophone polarization is parallel to a line of survey and the second geophone polarization is perpendicular to the line of survey.
Claim 7
Independent Claim
121 words
A method of seismic exploration, comprising the steps of: (a) imparting seismic energy into the earth and generating shear waves having first and second polarizations oblique to the unique axis of an anisotropic subterranean formation; (b) recording first and second signals representative of the earth's response to the first and second generated shear waves, respectively, with geophones having first and second polarizations with respect to the unique axis of the anisotropic subterranean formation; and (c) processing the first and second recorded signals with a measure of the angular orientation of their respective geophone polarizations with respect to the unique axis of the anisotropic formation so as to ameliorate the effects of shear wave birefringence on the first and second recorded signals.
Claim 8
Independent Claim
121 words
A method of seismic exploration, comprising the steps of: (a) imparting seismic energy into the earth and generating shear waves having first and second polarizations oblique to the unique axis of an anisotropic subterranean formation; (b) recording first and second signals representative of the earth's response to the first and second generated shear waves, respectively, with geophones having first and second polarizations with respect to the unique axis of the anisotropic subterranean formation; and (c) processing the first and second recorded signals with a measure of the angular orientation of their respective geophone polarizations with respect to the unique axis of the anisotropic formation so as to ameliorate the effects of shear wave birefringence on the first and second recorded signals.
Claim 9
Dependent Claim
14 words
The method of claim 6 wherein the first and second geophone polarizations are orthogonal.
Claim 10
Dependent Claim
19 words
The method of claim 6 wherein the first polarizations of the first generated shear waves and geophones are matched.
Claim 11
Dependent Claim
19 words
The method of claim 8 wherein the second polarizations of the second generated shear waves and geophones are matched.
Claim 12
Independent Claim
119 words
A method of seismic exploration, comprising the steps of: (a) imparting seismic energy into the earth and generating shear waves having first and second polarizations oblique to the unique axis of the anisotropic subterranean formation; (b) recording first and second signals representative of the earth's response to the first and second generated shear waves, respectively, with geophones having a first polarization with respect to the unique axis of the anisotropic subterranean formation; and (c) processing the first and second recorded signals with a measured of the angular orientation of the geophone polarization with respect to the unique axis of the anisotropic formation so as to ameliorate the effects of shear wave birefringence on the first and second recorded signals.
Claim 13
Independent Claim
119 words
A method of seismic exploration, comprising the steps of: (a) imparting seismic energy into the earth and generating shear waves having first and second polarizations oblique to the unique axis of the anisotropic subterranean formation; (b) recording first and second signals representative of the earth's response to the first and second generated shear waves, respectively, with geophones having a first polarization with respect to the unique axis of the anisotropic subterranean formation; and (c) processing the first and second recorded signals with a measured of the angular orientation of the geophone polarization with respect to the unique axis of the anisotropic formation so as to ameliorate the effects of shear wave birefringence on the first and second recorded signals.
Claim 14
Dependent Claim
22 words
The method of claim 10 wherein the first polarizations of the generated shear waves and the polarization of the geophone are matched.
Claim 15
Dependent Claim
23 words
The method of claim 10 wherein the second polarization of the generated shear waves and and the polarization of the geophone are orthogonal.
Claim 16
Dependent Claim
18 words
The method of claim 10 wherein the first and second polarization of the generated shear waves are orthogonal.
References Cited (Backward Citations)
US3378096A
Cited
US4789969A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |