Seismic data acquisition with varying distance between seismic vessels
A method for acquiring seismic data comprises operating a seismic vessel towing at least one of a seismic streamer with a plurality of seismic sensors and a seismic source. The inline distance between the vessel and one or more other vessels is adjusted according to a predefined function, where the seismic vessels travel along offset seismic acquisition lines, by increasing and reducing the in-line distance during the acquisition of the seismic data.
1. A method for acquiring seismic data, comprising:
operating a first seismic vessel towing at least one seismic streamer comprising a plurality of seismic sensors; and
operating a second seismic vessel towing at least one seismic source;
wherein the first seismic vessel follows a first seismic acquisition line and the second seismic vessel follows a second seismic acquisition line that is offset from the first seismic acquisition line; and
during acquisition of the seismic data, adjusting a speed of the first seismic vessel to achieve a desired in-line distance between the first seismic vessel and the second seismic vessel according to a first predefined distance function;
wherein the first seismic vessel is configured to travel at a variable velocity following the first seismic acquisition line to adjust the in-line distance from the second seismic vessel following the second seismic acquisition line that is offset from the first seismic acquisition line; and
wherein the in-line distance is reduced from a first distance to a second distance during a first time period and increased from the second distance to the first distance in a second time period.
2. The method of claim 1 , wherein the first seismic vessel and the second seismic vessel travel along substantially straight seismic acquisition lines.
3. The method of claim 1 , wherein adjusting the in-line distance between the first seismic vessel and the second seismic vessel comprises adjusting a speed of one or more of the seismic vessels to achieve a desired distance function by cyclically:
reducing the in-line distance between the first seismic vessel and the second seismic vessel; and
increasing the in-line distance between the first seismic vessel and the second seismic vessel.
4. The method of claim 1 , wherein adjusting the in-line distance between the first seismic vessel and the second seismic vessel comprises:
operating the first seismic vessel at a constant first velocity following the first seismic acquisition line; and
operating the second seismic vessel at a variable second velocity following the second seismic acquisition line.
5. The method of claim 1 , wherein:
the first seismic vessel and the second seismic vessel each tows a seismic source; and
the seismic sources towed by the first and second seismic vessels are configured to fire substantially simultaneously.
6. The method of claim 1 , wherein the first and second seismic acquisition lines are parallel.
7. The method of claim 1 , wherein an offset between the first seismic acquisition line and the second seismic acquisition line is determined by a number of said at least one seismic streamer towed by the first seismic vessel.
8. A method for acquiring seismic data, comprising:
operating a first seismic vessel towing at least one seismic streamer comprising a plurality of seismic sensors; and
operating a second seismic vessel towing at least one seismic source;
wherein the first seismic vessel follows a first seismic acquisition line and the second seismic vessel follows a second seismic acquisition line that is offset from the first seismic acquisition line; and
during acquisition of the seismic data, adjusting an in-line distance between the first seismic vessel and the second seismic vessel according to a first predefined function;
repeating the acquisition of the seismic data along a previously travelled seismic acquisition line by the first seismic vessel and the second seismic vessel; and
during the repeated acquisition, adjusting the in-line distance between the first seismic vessel and the second seismic vessel according to a second predefined function.
9. A non-transitory computer readable storage medium carrying a program product comprising computer-readable instructions which, when executed on a computer processor, are configured to perform a method comprising:
operating a first seismic vessel towing at least one seismic streamer comprising a plurality of seismic sensors; and
operating a second seismic vessel towing at least one seismic source;
wherein the first seismic vessel follows a first seismic acquisition line and the second seismic vessel follows a second seismic acquisition line offset from the first seismic acquisition line; and
during acquisition of seismic data, adjusting a speed of the first seismic vessel to achieve a desired in-line distance between the first seismic vessel and the second seismic vessel according to a first predefined distance function;
wherein the first seismic vessel is configured to travel at a variable velocity following the first seismic acquisition line to adjust the in-line distance from the second seismic vessel following the second seismic acquisition line that is offset from the first seismic acquisition line; and
wherein the in-line distance is reduced from a first distance to a second distance during a first time period and increased from the second distance to the first distance in a second time period.
10. The computer readable storage medium of claim 9 , wherein the first seismic vessel and the second seismic vessel travel along substantially straight seismic acquisition lines.
11. The computer readable storage medium claim 9 , the method further comprising:
repeating the acquisition of the seismic data along a previously travelled seismic acquisition line by the first seismic vessel and the second seismic vessel; and
during the repeated acquisition, adjusting the in-line distance between the first seismic vessel and the second seismic vessel according to a second predefined function.
12. The computer readable storage medium of claim 9 , wherein adjusting the in-line distance between the first seismic vessel and the second seismic vessel comprises adjusting a speed of one or more of the seismic vessels to achieve a desired distance function by cyclically:
reducing the in-line distance between the first seismic vessel and the second seismic vessel; and
increasing the in-line distance between the first seismic vessel and the second seismic vessel.
13. The computer readable storage medium of claim 9 , wherein adjusting the in-line distance between the first seismic vessel and the second seismic vessel comprises:
operating the first seismic vessel at a constant first velocity following the first acquisition line; and
operating the second seismic vessel at a variable second velocity following the second seismic acquisition line.
14. The computer readable storage medium of claim 9 , wherein:
the first seismic vessel and the second seismic vessel each tows a seismic source; and
the seismic sources towed by the first and second seismic vessels are configured to fire substantially simultaneously.
15. The computer readable storage medium claim 9 , wherein the first and second seismic acquisition lines are parallel.
16. The computer readable storage medium claim 9 , wherein an offset between the first seismic acquisition line and the second seismic acquisition line is determined by a number of said at least one seismic streamer towed by the first seismic vessel.
17. A seismic vessel configured to:
tow at least one of one or more seismic streamers and a seismic source; and
during acquisition of seismic data, adjust a speed of the seismic vessel to achieve a desired in-line distance from another seismic vessel according to a distance function;
wherein the seismic vessel is configured to travel at a variable velocity following a first seismic acquisition line to adjust the in-line distance from the other seismic vessel following a second seismic acquisition line that is offset from the first seismic acquisition line; and
wherein the in-line distance is reduced from a first distance to a second distance during a first time period and increased from the second distance to the first distance in a second time period.
18. The seismic vessel of claim 17 , further configured to:
determine a position of the seismic vessel; and
based on the determined position, adjust a speed the seismic vessel to achieve the distance function.
19. The seismic vessel of claim 17 , further configured to:
determine whether the seismic vessel is approaching an area of interest; and
in response to determining that the seismic vessel is approaching an area of interest, adjust the distance function.
20. The seismic vessel of claim 17 , wherein the first and second seismic acquisition lines are parallel.