US4817061A
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Seismic surveying technique for the detection of azimuthal variations in the earth's subsurface
Assignee: BP Corp North America Inc
•
Filing: 1984-07-20
•
Granted: 1989-03-28
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Expires: 2004-07-20
Abstract
Abstract Polarized shear wave surveys are performed to determine azimuthal variations in the earth's subsurface caused by fracture orientation and density. The surveys may be done by using the same polarization (either horizontal or vertical) shear waves along two different seismic lines of profile, or by using different polarization shear waves along one common line of profile. The survey data are then processed and compared; any differences constitute a measure of fracture orientation and density. Subsurface zones of high fracture density, once identified, have been found to afford a higher likelihood of successful well completion.
Inventors
- 👤 Richard M. Alford
- 👤 Heloise B. Lynn
- 👤 Leon A. Thomsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:10
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/28; G01V1/284; G01V2210/00; G01V2210/60; G01V2210/62; G01V2210/626
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
169 words
A method of surveying the earth's subsurface formations to determine azimuthal variations in the earth's subsurface comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction along a first seismic line of profile; (b) recording the reflected shear wave seismic energy with a first geophone having a polarization matching the polarization of the first seismic source to produce a first shear wave record; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction along a second seismic line of profile; (d) recording the reflected shear wave seismic energy with a second geophone having a polarization matching the polarization of the second seismic source to produce a second shear wave record; (e) processing the first and second shear wave records to produce a first and second shear wave section; and (f) comparing the first and second shear wave seismic sections to determine azimuthal variations in the earth's subsurface.
Claim 2
Independent Claim
169 words
A method of surveying the earth's subsurface formations to determine azimuthal variations in the earth's subsurface comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction along a first seismic line of profile; (b) recording the reflected shear wave seismic energy with a first geophone having a polarization matching the polarization of the first seismic source to produce a first shear wave record; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction along a second seismic line of profile; (d) recording the reflected shear wave seismic energy with a second geophone having a polarization matching the polarization of the second seismic source to produce a second shear wave record; (e) processing the first and second shear wave records to produce a first and second shear wave section; and (f) comparing the first and second shear wave seismic sections to determine azimuthal variations in the earth's subsurface.
Claim 3
Dependent Claim
57 words
The method of claim 1, further including the steps of: (a) imparting shear wave seismic energy into the earth with the first seismic source polarized perpendicular to the first seismic line of profile; and (b) imparting shear wave seismic energy into the earth with the second seismic source polarized perpendicular to the second seismic line of profile.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein the first and second seismic lines of profile cross.
Claim 5
Dependent Claim
17 words
The method of claim 3 wherein the first and second seismic lines of profile are substantially orthogonal.
Claim 6
Dependent Claim
57 words
The method of claim 1, further including the steps of: (a) imparting shear wave seismic energy into the earth with the first seismic source polarized parallel to the first seismic line of profile; and (b) imparting shear wave seismic energy into the earth with the second seismic source polarized parallel to the second seismic line of profile.
Claim 7
Dependent Claim
15 words
The method of claim 5 wherein the first and second seismic lines of profile cross.
Claim 8
Dependent Claim
17 words
The method of claim 6 wherein the first and second seismic lines of profile are substantially orthogonal.
Claim 9
Dependent Claim
17 words
The method of claim 1 wherein the first and second seismic lines of profile are substantially collinear.
Claim 10
Dependent Claim
15 words
The method of claim 8 wherein the first and second seismic source polarizations are orthogonal.
Claim 11
Dependent Claim
25 words
The method of claim 1 further including the step of: conducting a compressional wave seismic survey along the first and second seismic lines of profile.
Claim 12
Dependent Claim
21 words
The method of claim 1 further comprising the step of: determining fracture density from the azimuthal variations in the earth's subsurface.
Claim 13
Dependent Claim
54 words
The method of claim 1, wherein: (a) said step of processing the first and second shear wave records includes determining the arrival times of shear wave events and (b) said step of comparing the first and second seismic sections includes determining differences in shear wave event arrival times in the two shear wave sections.
Claim 14
Dependent Claim
54 words
The method of claim 1, wherein: (a) said step of processing the first and second shear wave records includes determining reflection amplitudes for events in the shear wave sections; and (b) said step of comparing the first and second seismic sections includes comparing reflection amplitudes for corresponding events in the two shear wave sections.
Claim 15
Dependent Claim
20 words
The method of claim 1 further including the step of: locating regions of oriented fractures within the earth's subsurface formations.
Claim 16
Dependent Claim
27 words
The method of claim 14 further including the step of: locating one of the seismic lines of profile substantially parallel to the orientation of the oriented fractures.
Claim 17
Dependent Claim
28 words
The method of claim 1 wherein: said step of comparing the first and second seismic sections includes comparing waveforms in corresponding events in the two shear wave sections.
Claim 18
Independent Claim
204 words
A method of surveying subsurface earth formations along two crossing seismic lines to investigate azimuthal variations in subsurface formations, comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction at selected points along a first seismic line of profile; (b) recording the response of the earth formations to the shear wave seismic energy at selected points on the first seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along a second seismic line of profile which crosses the first seismic line of profile; (d) recording the response of the earth formations to the shear wave seismic energy at selected points on the second seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source; and (e) processing both recorded responses to form a sher wave seismic section for each of the first and second seismic lines of profile to determine the presence of fractures and their orientation and density in the subsurface formations.
Claim 19
Independent Claim
204 words
A method of surveying subsurface earth formations along two crossing seismic lines to investigate azimuthal variations in subsurface formations, comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction at selected points along a first seismic line of profile; (b) recording the response of the earth formations to the shear wave seismic energy at selected points on the first seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along a second seismic line of profile which crosses the first seismic line of profile; (d) recording the response of the earth formations to the shear wave seismic energy at selected points on the second seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source; and (e) processing both recorded responses to form a sher wave seismic section for each of the first and second seismic lines of profile to determine the presence of fractures and their orientation and density in the subsurface formations.
Claim 20
Dependent Claim
130 words
The method of claim 17 further including the steps of: (a) imparting compressional wave seismic energy into the earth with a third seismic source at selected points along the first seismic line of profile; (b) recording the response of the earth formations to the compressional wave seismic energy at selected points on the first seismic line of profile; (c) imparting compressional wave seismic energy into the earth with a fourth seismic source at selected points along the second seismic line of profile; (d) recording the response of the earth formations to the compressional wave seismic energy at selected points on the second seismic line of profile; and (e) processing the recorded responses to form a compressional wave seismic section for each of the first and second seismic lines of profile.
Claim 21
Dependent Claim
32 words
The method of claim 17 wherein the step of processing both recorded responses includes determining the presence of fractures and their orientation and density at the intersection of the two seismic lines.
Claim 22
Dependent Claim
22 words
The method of claim 17, wherein the crossing seismic lines of profile are substantially orthogonal to each other along the earth's surface.
Claim 23
Dependent Claim
24 words
The method of claim 17, wherein the first and second seismic lines intersect over an area where oriented fractures are suspected to be present.
Claim 24
Dependent Claim
24 words
The method of claim 17, wherein one of the seismic lines of profile is located substantially parallel to the suspected orientation of the fractures.
Claim 25
Dependent Claim
24 words
The method of claim 17, wherein one of the seismic lines of profile is located substantially perpendicular to the suspected orientation of the fractures.
Claim 26
Independent Claim
189 words
A method of surveying subsurface earth formations along a single seismic line of profile to investigate azimuthal variations in the subsurface formations; comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction at selected points along the seismic line of profile; (b) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along the seismic line of profile; (d) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source; and (e) processing the recorded response to produce two shear wave seismic sections along the seismic line of profile to determine the presence of fractures and their orientation and density in the formation.
Claim 27
Independent Claim
189 words
A method of surveying subsurface earth formations along a single seismic line of profile to investigate azimuthal variations in the subsurface formations; comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction at selected points along the seismic line of profile; (b) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along the seismic line of profile; (d) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source; and (e) processing the recorded response to produce two shear wave seismic sections along the seismic line of profile to determine the presence of fractures and their orientation and density in the formation.
Claim 28
Dependent Claim
23 words
The method of claim 24 further including laying out the seismic line of profile substantially parallel to the suspected orientation of the fractures.
Claim 29
Dependent Claim
23 words
The method of claim 24 further including laying out the seismic line of profile substantially perpendicular to the suspected orientation of the fracture.
Claim 30
Dependent Claim
65 words
The method of claim 24 further including: (a) imparting compressional wave seismic energy into the earth with a third seismic source at selected points along the seismic line of profile; (b) recording the response of the earth's formations to the compressional wave seismic energy at selected points along the seismic line of profile; and (c) processing the response to form a compressional wave seismic section.
Claim 31
Dependent Claim
22 words
The method of claim 24 wherein the first and second polarizations of the seimic first and second seismic sources are mutually orthogonal.
Claim 32
Dependent Claim
30 words
The method of claim 28 wherein the first and second polarizations of the seismic first and second seismic sources are mutually orthogonal with respect to the seismic line of profile.
Claim 33
Independent Claim
138 words
A method for acquiring seismic data in locations having azimuthally anisotropic subsurface formations comprising the following steps: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction along a first seismic line of profile; (b) recording the earth's response to the imparted shear wave seismic energy with a first geophone having a polarization matching the polarization of the first seismic source to produce a first shear wave record; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction along a second seismic line of profile; and (d) recording the earth's response to the imparted shear wave seismic energy with a second geophone having a polarization matching the polarization of the first seismic source to produce a second shear wave record.
Claim 34
Independent Claim
138 words
A method for acquiring seismic data in locations having azimuthally anisotropic subsurface formations comprising the following steps: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction along a first seismic line of profile; (b) recording the earth's response to the imparted shear wave seismic energy with a first geophone having a polarization matching the polarization of the first seismic source to produce a first shear wave record; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction along a second seismic line of profile; and (d) recording the earth's response to the imparted shear wave seismic energy with a second geophone having a polarization matching the polarization of the first seismic source to produce a second shear wave record.
Claim 35
Dependent Claim
47 words
The method of claim 30 further including the steps of: (a) processing the first and second shear wave recod to produce a first and second shear wave section; and (b) comparing the first and second shear wave seismic sections to determine azimuthal variations in the earth's subsurface.
Claim 36
Dependent Claim
57 words
The method of claim 30 further including the steps of: (a) imparting shear wave seismic energy into the earth with the first seismic source polarized perpendicular to the first seismic line of profile; and (b) imparting shear wave seismic energy into the earth with the second seismic source polarized perpendicular to the second seismic line of profile.
Claim 37
Dependent Claim
15 words
The method of claim 32 wherein the first and second seismic lines of profile cross.
Claim 38
Dependent Claim
17 words
The method of claim 33 wherein the first and second seismic lines of profile are substantially orthogonal.
Claim 39
Dependent Claim
57 words
The method of claim 30 further including the steps of: (a) imparting shear wave seismic energy into the earth with the first seismic source polarized parallel to the first seismic line of profile; and (b) imparting shear wave seismic energy into the earth with the second seismic source polarized parallel to the second seismic line of profile.
Claim 40
Dependent Claim
15 words
The method of claim 35 wherein the first and second seismic lines of profile cross.
Claim 41
Dependent Claim
17 words
The method of claim 36 wherein the first and second seismic lines of profile are substantially orthogonal.
Claim 42
Dependent Claim
17 words
The method of claim 30 wherein the first and second seismic lines of profile are substantially collinear.
Claim 43
Dependent Claim
17 words
The method of claim 38 wherein the first and second shear wave seismic source polarizations are orthogonal.
Claim 44
Dependent Claim
61 words
The method of claim 30 further including the steps of: (a) imparting compressional wave seismic energy into the earth with a third seismic source along the first and second seismic lines of profile; and (b) recording the earth's response to the imparted compressional wave seismic energy with a third geophone adapted to detect compressional waves to produce a compressional wave record.
Claim 45
Independent Claim
162 words
A method of surveying azimuthally subsurface earth formations along two crossing seismic lines of profile comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction at selected points along a first seismic line of profile; (b) recording the response of the earth formations to the shear wave seismic energy at selected points on the first seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along a second seismic line of profile which crosses the first seismic line of profile; and (d) recording the response of the earth formations to the shear wave seismic energy at selected points on the second seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source.
Claim 46
Independent Claim
162 words
A method of surveying azimuthally subsurface earth formations along two crossing seismic lines of profile comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in a first direction at selected points along a first seismic line of profile; (b) recording the response of the earth formations to the shear wave seismic energy at selected points on the first seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along a second seismic line of profile which crosses the first seismic line of profile; and (d) recording the response of the earth formations to the shear wave seismic energy at selected points on the second seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source.
Claim 47
Dependent Claim
49 words
The method of claim 41 further including the steps of: processing both recorded shear wave responses to form a shear wave seismic section for each of the first and second seismic lines of profile to determine the presence of fractures and their orientation and density in the subsurface formations.
Claim 48
Dependent Claim
107 words
The method of claim 41 further including the steps of: (a) imparting compressional wave seismic energy into the earth with a third seismic source at selected points along the first seismic line of profile; (b) recording the response of the earth formations to the compressional wave seismic energy at selected points on the first seismic line of profile; (c) imparting compressional wave seismic energy into the earth with a fourth seismic source at selected points along the second seismic line of profile; and (d) recording the response of the earth formations to the compressional wave seismic energy at selected points on the second seismic line of profile.
Claim 49
Independent Claim
151 words
A method of surveying azimuthally anisotropic subsurface earth formations along a single seismic line of profile comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in the first direction at selected points along a seismic line of profile (b) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along the seismic line of profile; and (d) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source.
Claim 50
Independent Claim
151 words
A method of surveying azimuthally anisotropic subsurface earth formations along a single seismic line of profile comprising the steps of: (a) imparting shear wave seismic energy into the earth with a first seismic source polarized in the first direction at selected points along a seismic line of profile (b) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the first seismic source; (c) imparting shear wave seismic energy into the earth with a second seismic source polarized in a second direction at selected points along the seismic line of profile; and (d) recording the response of the earth's formations to the shear wave seismic energy at selected points along the seismic line of profile with a geophone having a polarization matching the polarization of the second seismic source.
Claim 51
Dependent Claim
44 words
The method of claim 41 further including the step of: (a) processing the recorded shear wave responses to produce two shear wave seismic sessions along the seismic lines of profile to determine the presence of fractures and their orientation and density in the formation.
Claim 52
Dependent Claim
69 words
The method of claim 44 further including the steps of: (a) imparting compressional wave seismic energy into the earth with a third seismic source at selected points along the seismic line of profile; (b) recording the response of the earth's formations to the compressional wave seismic energy at selected points along the seismic line of profile; and (c) processing the compressional response to form a compressional wave seismic section.
Claim 53
Dependent Claim
22 words
The method of claim 44 wherein the first and second polarizations of the seismic first and second sources energy are mutually orthogonal.
Claim 54
Dependent Claim
31 words
The method of claim 47 wherein the first and second polarizations of the the first and second sources seismic energy are mutually orthogonal with respect to the seismic line of profile.
Claim 55
Independent Claim
119 words
A method for determining azimuthal variations in the earth's subsurface comprising the steps of: (a) displaying a first record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a first direction along a first seismic line of profile and received by a first geophone havng a matched polarization; (b) displaying a second record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a second direction along a second seismic line of profile and received by a second geophone having a matched polarization; and (c) comparing the first and second records of shear wave seismic energy to determine azimuthal variations in the earth's subsurface.
Claim 56
Independent Claim
119 words
A method for determining azimuthal variations in the earth's subsurface comprising the steps of: (a) displaying a first record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a first direction along a first seismic line of profile and received by a first geophone havng a matched polarization; (b) displaying a second record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a second direction along a second seismic line of profile and received by a second geophone having a matched polarization; and (c) comparing the first and second records of shear wave seismic energy to determine azimuthal variations in the earth's subsurface.
Claim 57
Independent Claim
118 words
A method for determining azimuthal variations in the earth's subsurface comprising the steps of: (a) displaying a first record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a first direction along a seismic line of profile and received by a first geophone having a matched polarization; (b) displaying a second record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a second direction along the seismic line of profile and received by a second geophone having a matched polarization; and (c) comparing the first and a second records of shear wave seismic energy to determine azimuthal variations in the earth's subsurface.
Claim 58
Independent Claim
118 words
A method for determining azimuthal variations in the earth's subsurface comprising the steps of: (a) displaying a first record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a first direction along a seismic line of profile and received by a first geophone having a matched polarization; (b) displaying a second record of shear wave seismic energy imparted into the earth by a shear wave seismic source polarized in a second direction along the seismic line of profile and received by a second geophone having a matched polarization; and (c) comparing the first and a second records of shear wave seismic energy to determine azimuthal variations in the earth's subsurface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |