US4476553A
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US
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Method of determining the signatures of arrays of marine seismic sources
Assignee: Britoil Ltd
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Filing: 1982-05-25
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Granted: 1984-10-09
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Expires: 2002-05-25
Abstract
Abstract In order to determine the signature of an array of n seismic sources 21 to 27, for instance marine seismic sources in the form of air guns, the array is actuated and the emitted pressure wave is measured at n independent points whose positions will respect to the array are known by hydrophones 31 to 37. The measurements are processed to produce n equivalent signatures of the n sources taking into account the interactions therebetween. The signature of the array is then determined merely by superposing the n equivalent signatures.
Inventors
- 👤 Antoni M. Ziolkowski
- 👤 Leslie Hatton
- 👤 Gregory E. Parkes
- 👤 Tor-Arvid Haugland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:31
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/003; G01V1/006; G01V13/00
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
191 words
A method of determining the signature of an array of n seismic sources, comprising the steps of: providing an array of n marine seismic sources as the array of n seismic sources, and providing n hydrophones for measuring the emitted pressure wave; actuating the array of n seismic sources; measuring the emitted pressure wave at n independent points whose positions are known with respect to the array; processing the measurements so as to produce n equivalent signatures of the n sources taking into account the interactions therebetween, said processing step comprising forming n simultaneous equations ##EQU18## where h i (t) is the signal provided by the i th hydrophones, S i is the sensitivity of the i th hydrophone, a ij is the distance between the i th hydrophone and the j th seismic source, c is the speed of sound in water, t is time, and P' j (t) is the equivalent signature of the j th seismic source, and solving the n simultaneous equations for P' j (t) where j=1, 2, . . . , n; and providing the signature of the array by superposing the n equivalent signatures.
Claim 2
Independent Claim
191 words
A method of determining the signature of an array of n seismic sources, comprising the steps of: providing an array of n marine seismic sources as the array of n seismic sources, and providing n hydrophones for measuring the emitted pressure wave; actuating the array of n seismic sources; measuring the emitted pressure wave at n independent points whose positions are known with respect to the array; processing the measurements so as to produce n equivalent signatures of the n sources taking into account the interactions therebetween, said processing step comprising forming n simultaneous equations ##EQU18## where h i (t) is the signal provided by the i th hydrophones, S i is the sensitivity of the i th hydrophone, a ij is the distance between the i th hydrophone and the j th seismic source, c is the speed of sound in water, t is time, and P' j (t) is the equivalent signature of the j th seismic source, and solving the n simultaneous equations for P' j (t) where j=1, 2, . . . , n; and providing the signature of the array by superposing the n equivalent signatures.
Claim 3
Dependent Claim
21 words
A method as set forth in claim 1, wherein each of the marine seismic sources is provided as an air gun.
Claim 4
Dependent Claim
45 words
A method as set forth in claim 2, comprising the further step of locating each hydrophone adjacent a respective one of the air guns but spaced therefrom by a distance such that the hydrophone does not penetrate the air bubble produced by the air gun.
Claim 5
Dependent Claim
55 words
A method as set forth in claim 1, wherein said step of providing the signature of the array comprises forming the signature P (t) of the array at any predetermined point by superposing the n equivalent signatures according to: ##EQU19## where r j is the distance from the j th source to the predetermined point.
Claim 6
Dependent Claim
19 words
An array of seismic sources whose signature has been determined by a method as set forth in claim 1.
Claim 7
Dependent Claim
16 words
Use of said array of seismic sources as set forth in claim 5 for collecting data.
Claim 8
Dependent Claim
17 words
Data collected by said use of said array of seismic sources as set forth in claim 6.
Claim 9
Independent Claim
263 words
A method of determining the signature of an array of n seismic sources, comprising the steps of: providing an array of n marine seismic sources as the array of n seismic sources, and providing n hydrophones for measuring the emitted pressure wave; actuating the array of n seismic sources; measuring the emitted pressure wave at n independent points whose positions are known with respect to the array; processing the measurements so as to produce n equivalent signatures of the n sources taking into account the interactions therebetween, said processing step comprising forming n simultaneous equations ##EQU20## where h i (t) is the signal provided by the i th hydrophone, S i is the sensitivity of the i th hudrophone, a ij is the distance between the i th hydophone and the j th seismic source, c is the speed of sound in water, t is time, P' j (t) is the equivialent signature of the j th seismic source, o' j (t) is the equvalent signature of a virtual seismic source corresponding the j th seismic source and formed by relfection at the sea surface, b ij is the distance from the i th hydrophone to the j th virtual source, q' j (t)=R·P' j (t), R is the coefficient of reflection of the sea surface, and the amplitude of the pressure wave at the sea surface does not exceed atmospheric pressure, and solving the n simultaneous equations for P' j (t) where i=1, 2, . . . , n; and providing the signature of the array by superposing the n equivalent signatures.
Claim 10
Independent Claim
263 words
A method of determining the signature of an array of n seismic sources, comprising the steps of: providing an array of n marine seismic sources as the array of n seismic sources, and providing n hydrophones for measuring the emitted pressure wave; actuating the array of n seismic sources; measuring the emitted pressure wave at n independent points whose positions are known with respect to the array; processing the measurements so as to produce n equivalent signatures of the n sources taking into account the interactions therebetween, said processing step comprising forming n simultaneous equations ##EQU20## where h i (t) is the signal provided by the i th hydrophone, S i is the sensitivity of the i th hudrophone, a ij is the distance between the i th hydophone and the j th seismic source, c is the speed of sound in water, t is time, P' j (t) is the equivialent signature of the j th seismic source, o' j (t) is the equvalent signature of a virtual seismic source corresponding the j th seismic source and formed by relfection at the sea surface, b ij is the distance from the i th hydrophone to the j th virtual source, q' j (t)=R·P' j (t), R is the coefficient of reflection of the sea surface, and the amplitude of the pressure wave at the sea surface does not exceed atmospheric pressure, and solving the n simultaneous equations for P' j (t) where i=1, 2, . . . , n; and providing the signature of the array by superposing the n equivalent signatures.
Claim 11
Dependent Claim
21 words
A method as set forth in claim 8, wherein each of the marine seismic sources is provided as an air gun.
Claim 12
Dependent Claim
45 words
A method as set forth in claim 9, comprising the further step of locating each hydrophone adjacent a respective one of the air guns but spaced therefrom by a distance such that the hydrophone does not penetrate the air bubble produced by the air gun.
Claim 13
Dependent Claim
55 words
A method as set forth in claim 8, wherein said step of providing the signature of the array comprises forming the signature P (t) of the array at any predetermined point by superposing the n equivalent signatures according to: ##EQU21## where r j is the distance from the j th source to the predetermined point.
Claim 14
Dependent Claim
19 words
An array of seismic sources whose signature has been determined by a method as set forth in claim 8.
Claim 15
Dependent Claim
16 words
Use of said array of seismic sources as set forth in claim 12 for collecting data.
Claim 16
Dependent Claim
17 words
Data collected by said use of said array of seismic sources as set forth in claim 13.
Claim 17
Independent Claim
289 words
A method of determining the signature of an array of n seismic sources, comprising the step of: providing an array of n marine seismic sources as the array of n seismic sources, and providing 2n hydrophones for measuring the emitted pressure wave, the amplitude of which pressure wave exceeds atmospheric pressure at the sea surface; actuating the array of n seismic sources; measuring the emitted pressure wave at n independent points whose positions are known with respect to the array; processing the measurements so as to produce n equivalent signatures of the n sources taking into account the interactions therebetween, said processing step comprising forming 2n simultaneous equations ##EQU22## where h i (t) is the signal provided by the ith hydrophone, S i is the sensitivity of the i th hydrophone, a ij is the distance between the i th hydrophone and the j th seismic source, c is the speed of sound in water, t is time, P' k (t) for j=1, 2, . . . , n is the equivalent signature of the j th seismic source, and P' j (t) for j=n+1, . . . , 2n is the equivalent signature of a virtual seismic source corresponding to the (j-n) th seismic source and formed by relfection in the sea surface, and solving the 2n simultaneous equations for P' j (t) where j=1, 2, . . . , 2n; and, providing the signature of the array by superposing the n equivalent signatures, said providing step comprising forming the signature P (t) of the array at any predetermined point by superposing the 2u equivalent signatures according to ##EQU23## where r j is the distance from the j th seismic source and virtual source to the predetermined point.
Claim 18
Independent Claim
289 words
A method of determining the signature of an array of n seismic sources, comprising the step of: providing an array of n marine seismic sources as the array of n seismic sources, and providing 2n hydrophones for measuring the emitted pressure wave, the amplitude of which pressure wave exceeds atmospheric pressure at the sea surface; actuating the array of n seismic sources; measuring the emitted pressure wave at n independent points whose positions are known with respect to the array; processing the measurements so as to produce n equivalent signatures of the n sources taking into account the interactions therebetween, said processing step comprising forming 2n simultaneous equations ##EQU22## where h i (t) is the signal provided by the ith hydrophone, S i is the sensitivity of the i th hydrophone, a ij is the distance between the i th hydrophone and the j th seismic source, c is the speed of sound in water, t is time, P' k (t) for j=1, 2, . . . , n is the equivalent signature of the j th seismic source, and P' j (t) for j=n+1, . . . , 2n is the equivalent signature of a virtual seismic source corresponding to the (j-n) th seismic source and formed by relfection in the sea surface, and solving the 2n simultaneous equations for P' j (t) where j=1, 2, . . . , 2n; and, providing the signature of the array by superposing the n equivalent signatures, said providing step comprising forming the signature P (t) of the array at any predetermined point by superposing the 2u equivalent signatures according to ##EQU23## where r j is the distance from the j th seismic source and virtual source to the predetermined point.
Claim 19
Dependent Claim
19 words
An array of seismic sources whose signature has been determined by a method as set forth in claim 15.
Claim 20
Dependent Claim
16 words
Use of said array of seismic sources as set forth in claim 16 for collecting data.
Claim 21
Dependent Claim
17 words
Data collected by said use of said array of seismic sources as set forth in claim 17.
Claim 22
Independent Claim
106 words
A method of determining the signature of an array of n seismic sources, comprising the steps of: actuating the array of n seismic sources; measuring the emitted pressure wave in the near field of the array at n independent points whose positions are known with respect to the n seismic sources; processing the measurements by taking into account the interactions between the n sources so as to construct at least notionally an equivalent array of n non-interacting independent sources having n equivalent signatures which are superposable to provide the signature of the array; and determining the signature of the array by superposing the n equivalent signatures.
Claim 23
Independent Claim
106 words
A method of determining the signature of an array of n seismic sources, comprising the steps of: actuating the array of n seismic sources; measuring the emitted pressure wave in the near field of the array at n independent points whose positions are known with respect to the n seismic sources; processing the measurements by taking into account the interactions between the n sources so as to construct at least notionally an equivalent array of n non-interacting independent sources having n equivalent signatures which are superposable to provide the signature of the array; and determining the signature of the array by superposing the n equivalent signatures.
Claim 24
Dependent Claim
38 words
A method as set forth in claim 19, comprising the further steps of providing an array of n marine seismic sources as the array of n seismic sources, and providing n hydrophones for measuring the emitted pressure wave.
Claim 25
Dependent Claim
21 words
A method as set forth in claim 20, wherein each of the marine seismic sources is provided as an air gun.
Claim 26
Dependent Claim
45 words
A method as set forth in claim 18, comprising the further step of locating each hydrophone adjacent a respective one of the air guns but spaced therefrom by a distance such that the hydrophone does not penetrate the air bubble produced by the air gun.
Claim 27
Dependent Claim
102 words
A method as set forth in claim 19, wherein said processing step comprises: forming n simultaneous equations ##EQU24## where h i (t) is the signal provided by the i th hydrophone, S i is the sensitivitly of the i th hydrophone, a ij is the distance between the i th hydrophone and the j th seismic source, c is the speed of sound in water, t is time, and P j ' (t) is the equivalent signature of the j th seismic source; and solving the n simultaneous equations for P j ' (t) where j=1, 2, . . . , n.
Claim 28
Dependent Claim
178 words
A method as set forth in claim 17, wherein said processing step comprises: forming n simultaneous equations ##EQU25## where h i (t) is the signal provided by the i th hydrophone, S i is the sensitivity of the i th hydrophone, a ij is the distance between the i th hydrophone and the j th seismic source, c is the speed of sound in water, t is time, P j ' (t) is the equivalent signature of the j th seismic source, q j ' (t) is the equivalent signature of a virtual seismic source correspondiang to the j th seismic source and formed by reflection at the sea surface, b ij is the distance from the i th hydrophone to the j th virtual source, q j ' (t)=R·P j ' 8t), R is the coefficient of reflection of the sea surface, and the amplitude of the pressure wave at the sea surface does not exceed atmospheric pressure; and solving the n simultaneous equations for P j ' (t) where i=1, 2, . . . , n.
Claim 29
Dependent Claim
56 words
A method as set forth in claim 23, wherein said step of providiang the signature of the array comprises forming the signature P (t) of the array at any predetermined point by superposing the n equivalent signatures according to : ##EQU26## where r j is the distance from the j th source to the predetermined point.
Claim 30
Dependent Claim
55 words
A method as set forth in claim 24, wherein said step of providing the signature of the array comprises forming the signature P (t) of the array at any predetermined point by superposing the n equivalent signatures according to: ##EQU27## where r j is the distance from the j th source to the predetermined point.
Claim 31
Dependent Claim
51 words
A method as set forth in claim 20, comprising the further steps of providing an array of n marine seismic sources as the array of n seismic sources, and providing 2n hydrophones for measuring the emitted pressure wave, the amplitude of which pressure wave exceeds atmospheric pressure at the sea surface.
Claim 32
Dependent Claim
144 words
A method as set forth in claim 27, wherein said processing step comprises: forming 2n simultaneous equations ##EQU28## where h i (t) is the signal provided by the ith hydrophone, S i is the sensitivity of the i th hydrophone, a ij is the distance between the i th hydrophone and the j th seismic source, c is the speed of sound in water, t is time, P k ' (t) for j=1, 2, . . . , n is the equivalent signature of the j th seismic source, and P j ' (t) for j=n+1, . . . , 2n is the equivalent signature of a virtual seismic source corresponding to the (j-n) th seismic source and formed by reflection in the sea surface; and solving the 2n simultaneous equations for P j ' (t) where j=1, 2, . . . , 2n.
Claim 33
Dependent Claim
59 words
A method as set forth in claim 28, wherein said step of providing the signature of the array comprises forming the signature P (t) of the array at any predetermined point by superposing the 2u equivalent signatures according to ##EQU29## where r j is the distance from the j th seismic source and virtual source to the predetermined point.
Claim 34
Dependent Claim
19 words
An array of seismic sources whose signature has been determined by a method as set forth in claim 19.
Claim 35
Dependent Claim
16 words
Use of said array of seismic sources as set forth in claim 30 for collecting data.
Claim 36
Dependent Claim
17 words
Data colected by said use of said array of seismic sources as set forth in claim 31.
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) | 1987-10-09 | 1988-04-09 | 1988-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-09 | 1992-04-09 | 1992-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-09 | 1996-04-09 | 1996-10-09 | $7700.00 | Window Closed / Lapsed |