Method and apparatus for marine wide azimuth towed steamer seismic acquisition

Patent metadata

Field	Value
Publication number	US-8942060-B2
Application number	US-201113196614-A
Country	US
Kind code	B2
Filing date	Aug 2, 2011
Priority date	Aug 2, 2010
Publication date	Jan 27, 2015
Grant date	Jan 27, 2015

Abstract

This is a method of acquiring marine wide azimuth towed streamer seismic data. Preferably, a recording boat which tows a plurality of seismic streamers and at least one source may be accompanied by a plurality of source boats that each tow at least one source. The source boats may preferably activate their respective sources such that the subsurface reflections generated by each source interfere. The time separation between successive shots may preferably be a random variable related to the lowest frequency of interest in the data. Additionally, the source boats may preferably be alternatively fired from the head and tail of the recording streamers.

First claim

What is claimed is:

1. A method of seismic exploration, comprising:
(a) positioning a seismic receiver boat at a location proximate a subsurface target, said seismic receiver boat pulling at least one seismic streamer therebehind, said at least one seismic streamer having a head end proximate to said receiver boat and a trailing end remote from said receiver boat;
(b) positioning a first seismic source proximate to either said head end of said at least one seismic streamers or said trailing end of said plurality of seismic streamers;
(c) positioning a second seismic source proximate an opposite end of said at least one seismic streamers from said first seismic source;
(d) activating said first seismic source;
(e) waiting a random length of time following said first seismic source activation and then activating said second seismic source, said random length of time being selected such that recorded seismic energy from said second source activation interferes with recorded seismic energy from said first source activation;
(f) continuously recording reflected seismic energy from said activation of said first seismic source and from said activation of said second seismic source via said at least one seismic streamer, thereby obtaining a plurality of seismic traces that record at least said first and second seismic source activations;
(g) performing at least (a) through (f) a plurality of times at a plurality of different locations proximate to said subsurface target while continuously recording, thereby obtaining a blended source seismic survey comprised of a plurality of source activations, wherein a sequence comprises said performing of at least (a) through (f) said plurality of times, said sequence comprising two or more activations of at least one of said first seismic source and said second seismic source; and,
(h) using said blended source seismic survey to explore for hydrocarbons within said region of the subsurface.

2. The method of seismic exploration according to claim 1 , wherein there is a lowest frequency of interest in said blended source seismic survey and wherein said random length of time of (e) is chosen to be longer than a wavelength of said lowest frequency of interest in said blended seismic survey.

3. The method of seismic exploration according to claim 1 , wherein said first source comprises a plurality of marine air guns.

4. The method of claim 1 , wherein (h) comprises:
(h1) selecting a particular source activation from among said plurality of source activations in said blended source seismic survey,
(h2) separating said selected source activation from said blended source seismic survey by using sparse inversion, thereby obtaining a single source gather, and,
(h3) using said single source gather to explore for hydrocarbons within said region of the subsurface containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons.

5. The method of claim 1 , wherein (h) comprises:
(h1) selecting a particular source activation from among said plurality of source activations in said blended source seismic survey,
(h2) separating said selected source activation from said blended source seismic survey to obtain a single source gather by solving
d=ΓS m,

where,
d is said selected particular source activation,
m is said single source gather,
S is a matrix or operator that constrains m by requiring similarity between nearby source activations, and,
Γ is a blending matrix which describes at least an activation time of said particular source activation.

6. A method of seismic exploration, comprising:
(a) in a computer, accessing a blended source seismic survey collected by a method comprising:
(1) positioning a seismic receiver boat at a location proximate to a subsurface target, said seismic receiver boat pulling at least one seismic streamer therebehind, said at least one seismic streamer having a head end proximate to said receiver boat and a trailing end remote from said receiver boat;
(2) activating a first seismic source at a location proximate to said head end or said trailing end of said at least one seismic streamer;
(3) waiting a random length of time following said first seismic source activation and then activating a second seismic source at a location laterally offset from said at least one seismic streamer, said random length of time being selected such that seismic energy recorded by said at least one streamer from said second source activation interferes with recorded seismic energy from said first source activation;
(4) continuously recording reflected seismic energy from said activation of said first seismic source and from said activation of said second seismic source via said at least one seismic streamer, thereby obtaining a plurality of seismic traces that record at least said first and second seismic source activations;
(5) performing at least steps (1) through (4) a plurality of times at a plurality of different locations proximate to said subsurface region while continuously recording, thereby obtaining said blended source seismic survey, wherein a sequence comprises said performing of at least (1) through (4) said plurality of times, said sequence comprising two or more activations of at least one of said first seismic source and said second seismic source; and,

(b) using said blended source seismic survey to explore for hydrocarbons within subsurface region.

7. The method of seismic exploration according to claim 6 , wherein there is a lowest frequency of interest in said blended source seismic survey and wherein said random length of time of (a)(3) is chosen to be longer than a wavelength of said lowest frequency of interest in said blended seismic survey.

8. The method of seismic exploration according to claim 6 , wherein said first seismic source comprises a plurality of marine air guns.

9. The method of claim 6 , wherein (b) comprises:
(b1) selecting a particular source activation from among said plurality of source activations in said blended source seismic survey,
(b2) separating said selected source activation from said blended source seismic survey by using sparse inversion, thereby obtaining a single source gather, and,
(b3) using said single source gather to explore for hydrocarbons within said region of the subsurface containing structural or stratigraphic features conducive to the presence, migration, or accumulation of hydrocarbons.

10. The method of claim 6 , wherein step (b2) comprises:
(i) selecting a particular source activation from among said plurality of source activations in said blended source seismic survey,
(ii) separating said selected source activation from said blended source seismic survey to obtain a single source gather by solving
d =ΓS m,

where,
d is said selected particular source activation,
m is said single source gather,
S is a matrix or operator that constrains m by requiring similarity between nearby source activations, and, Γ is a blending matrix which describes at least an activation time of said particular source activation.

11. A method of seismic exploration, comprising:
(a) positioning a seismic receiver boat at a location proximate a subsurface target, said seismic receiver boat pulling at least one seismic streamer therebehind, said at least one seismic streamer having a head end proximate to said receiver boat and a trailing end remote from said receiver boat;
(b) positioning a first seismic source proximate to either said head end of said at least one seismic streamers or said trailing end of said plurality of seismic streamers;
(c) positioning a second seismic source laterally offset from said first seismic sou

Assignees

• Abma Raymond Lee
• Beaudoin Gerard
• Bp Corp North America Inc

Inventors

• Abma Raymond Lee
• Beaudoin Gerard

Classifications

• G01V1/3808 Primary

  Seismic data acquisition, e.g. survey design · CPC title

• G01V2210/244

  Radon transform · CPC title

• G01V2210/242

  F-k filtering, e.g. ground roll · CPC title

• G01V1/364

  Seismic filtering (G01V1/37 takes precedence) · CPC title

• G01V1/368

  Inverse filtering · CPC title