Marine seismic acquisition
A method of conducting multiple source, multiple signal seismic surveys in a marine environment are provided.
1. A method of acquiring and processing marine seismic data, said method comprising:
a) moving multiple seismic receivers through a body of water;
b) simultaneously with step (a), performing a series of periodic seismic sweeps including an initial seismic sweep and a subsequent seismic sweep by simultaneously energizing at least two seismic sources and acquiring source seismic data and reflected seismic data using multiple receivers, wherein the acquiring from the initial seismic sweep is collected by a first set of receivers while the acquiring from the subsequent seismic sweep is collected by a second set of receivers, wherein the first set is different from the second set;
c) reorganizing said source seismic data and/or said reflected seismic data based on common source-receiver centerpoints from different seismic sweeps, thereby generating reorganized seismic data; and
d) source separating said reorganized seismic data.
2. The method of claim 1 , wherein each seismic sweep includes exciting said at least two of said seismic sources for a period of 1 to 5 seconds.
3. The method of claim 1 , wherein the average time interval between said seismic sweeps is 2 to 30 seconds.
4. The method of claim 1 , wherein the vibratory energy emitted by said seismic sources during each sweep is encoded for source separation.
5. The method of claim 1 , wherein the vibratory energy emitted by said seismic sources during each sweep is phase encoded.
6. The method of claim 1 , wherein at least one seismic source emits vibratory energy from 1-150 Hz, 6-120 Hz, 1-60 Hz, 50-150 Hz, 1-80 Hz, 80-160 Hz and combinations thereof.
7. The method of claim 1 , wherein the power output of each of said seismic sources during each sweep is 1-500, 15-250, or 20-100 bar·meters·sec.
8. The method of claim 1 , wherein the cumulative power output of all said seismic sources during each seismic sweep is less than 100, 25, or 10 bar·meters·sec.
9. The method of claim 1 , wherein said reorganizing of step (c) includes grouping reflected seismic data from different sweeps and different receivers based on the common source-receiver centerpoints.
10. The method of claim 9 , further comprising acquiring source data during each of said seismic sweeps, wherein said source separating of step (d) includes performing a matrix inversion using said source data and said reorganized reflected seismic data.
11. The method of claim 9 , further comprising acquiring encoded source data during each of said seismic sweeps, wherein said seismic reflectivity values are determined by solving the equation
[
S
11
S
12
…
S
1
N
S
21
S
22
…
S
2
N
…
S
M
1
S
M
2
…
S
MN
]
[
h
1
h
2
…
h
N
]
=
[
R
1
R
2
…
R
M
]
.
wherein each S represents encoded source data for a particular sweep and a particular seismic source, wherein each R represents reorganized reflected data for a particular sweep, wherein M represents the number of sweeps being processed, wherein N represents the number of seismic sources being processed, wherein h represents said seismic reflectivity values.
12. A method of processing seismic data, said method comprising:
a) receiving seismic data including—
i) encoded source data for multiple sweeps of multiple seismic sources, wherein the multiple sweeps includes an initial sweep and a subsequent sweep, wherein said multiple sweeps include simultaneous excitation of said multiple seismic sources with said multiple seismic sources being at a substantially different location for each sweep,
ii) reflected seismic data acquired by multiple seismic receivers for each of said multiple sweeps, wherein a first set of receivers acquires the initial sweep and a second set of receivers acquires the subsequent sweep, wherein the first set and second set are different;
b) reorganizing said reflected seismic data based on common source-receiver centerpoints from different sweeps, thereby generating reorganized reflected seismic data; and
c) source separating said reorganized reflected seismic data.
13. The method of claim 12 , wherein each seismic sweep includes exciting said at least two of said seismic sources for a period of 1 to 5 seconds.
14. The method of claim 12 , wherein the average time interval between said seismic sweeps is 2 to 30 seconds.
15. The method of claim 12 , wherein said seismic sources are capable of emitting vibratory energy of controlled phase, frequency, and/or amplitude.
16. The method of claim 12 , wherein the vibratory energy emitted by said seismic sources during each sweep is encoded for source separation.
17. The method of claim 12 , wherein the vibratory energy emitted by said seismic sources during each sweep is phase encoded.
18. The method of claim 12 , wherein at least one seismic source emits vibratory energy from 1-150 Hz, 6-120 Hz, 1-60 Hz, 50-150 Hz, 1-80 Hz, 80-160 Hz and combinations thereof.
19. The method of claim 12 , wherein the power output of each of said seismic sources during each sweep is 1-500, 15-250, or 20-100 bar·meters·sec.
20. The method of claim 12 , wherein the cumulative power output of all said seismic sources during each seismic sweep is less than 100, 25, or 10 bar·meters·sec.
21. The method of claim 12 , wherein said reorganizing of step (c) includes grouping reflected seismic data from different sweeps and different receivers based on the common source-receiver centerpoints.
22. The method of claim 12 , further comprising acquiring source data during each of said seismic sweeps, wherein said source separating of step (d) includes performing a matrix inversion using said source data and said reorganized reflected seismic data.
23. The method of claim 12 , further comprising acquiring encoded source data during each of said seismic sweeps, wherein said seismic reflectivity values are determined by solving the equation
[
S
11
S
12
…
S
1
N
S
21
S
22
…
S
2
N
…
S
M
1
S
M
2
…
S
MN
]
[
h
1
h
2
…
h
N
]
=
[
R
1
R
2
…
R
M
]
.
wherein each S represents encoded source data for a particular sweep and a particular seismic source, wherein each R represents reorganized reflected data for a particular sweep, wherein M represents the number of sweeps being processed, wherein N represents the number of seismic sources being processed, wherein h represents said seismic reflectivity values.