Three-dimensional seismic acquisition system and method with dynamic resolution

Abstract

System and method for calculating a pre-plot for a marine seismic acquisition system. The method includes receiving as input a first number of autonomous underwater vehicles (AUVs) and a second number of source vessels; receiving a geometry of an area to be surveyed; receiving a set of naturally different regions and/or humanly set targets for the area to be surveyed; calculating a first sailing path for an AUV of the first number of AUVs; calculating a second sailing path for a source vessel of the second number of source vessels, based on the set of naturally different regions and/or humanly set targets; and entering the pre-plot into a navigation system of the AUV and the source vessel so that the AUV and source vessel dynamically change an offset distance between them, while sailing during a seismic survey, based on the naturally different regions and/or humanly set targets.

What is claimed is: 
     
         1 . A method for calculating a pre-plot for a marine seismic acquisition system, the method comprising:
 receiving as input a first number of autonomous underwater vehicles (AUVs), each having a seismic sensor, and a second number of source vessels;   receiving a geometry of an area to be surveyed;   receiving a set of naturally different regions and/or humanly set targets for the area to be surveyed;   calculating a first sailing path for an AUV of the first number of AUVs;   calculating a second sailing path for a source vessel of the second number of source vessels, based on the set of naturally different regions and/or humanly set targets, wherein the first sailing path and the second sailing path form the pre-plot; and   entering the pre-plot into a navigation system of the AUV and the source vessel so that the AUV and source vessel dynamically change an offset distance between them, while sailing during a seismic survey, based on the naturally different regions and/or humanly set targets.   
     
     
         2 . The method of  claim 1 , wherein the offset distance changes to achieve a better illumination and/or a better resolution. 
     
     
         3 . The method of  claim 1 , further comprising:
 receiving a geometry of the AUVs located over the area to be surveyed; and   calculating the second sailing path for the source vessel based on the geometry of the AUVs and the set of naturally different regions and/or humanly set targets.   
     
     
         4 . The method of  claim 1 , wherein the source vessel is programmed to sail farther from the AUV to achieve a better illumination. 
     
     
         5 . The method of  claim 1 , wherein the source vessel is programmed to sail closer to the AUV for achieving a better resolution. 
     
     
         6 . The method of  claim 1 , wherein the source vessels each tows at least one source and the sources are fired simultaneously. 
     
     
         7 . The method of  claim 1 , wherein the source vessels each tows at least one source and the sources are fired in a flip-flop manner. 
     
     
         8 . The method of  claim 1 , wherein naturally different regions include a gas volume or a salt dome. 
     
     
         9 . The method of  claim 1 , wherein the humanly set targets includes a deep target and a shallow target. 
     
     
         10 . A marine acquisition system comprising:
 a plurality of autonomous underwater vehicles (AUVs) having seismic sensors;   a source vessel that tows a first source;   coordinates of an AUV sail line stored at vessel corresponding AUV; and   coordinates of a source sail line stored at the source vessel,   wherein the coordinates of the source sail line are calculated based on a set of naturally different regions and/or humanly set targets that characterize a region to be surveyed.   
     
     
         11 . The system of  claim 10 , wherein an AUV of the plural AUVs and the source vessel dynamically change an offset distance between them, while sailing during a seismic survey, based on the naturally different regions and/or humanly set targets. 
     
     
         12 . The system of  claim 11 , wherein the offset distance changes to achieve a better illumination and/or a better resolution. 
     
     
         13 . The system of  claim 11 , wherein the coordinates of the source sail line are calculated based on a geometry of the AUV distributed over an area of interest and the set of naturally different regions and/or humanly set targets. 
     
     
         14 . The system of  claim 11 , wherein the first source and an additional second sources are fired simultaneously. 
     
     
         15 . The system of  claim 11 , wherein naturally different regions include a gas volume or a salt dome. 
     
     
         16 . The system of  claim 11 , wherein the humanly set targets includes a deep target and a shallow target. 
     
     
         17 . The system of  claim 11 , wherein the AUV sail line is straight from one edge to another edge of the region to be surveyed while the source sail line changes direction as a new region or target of the naturally different regions and/or humanly set targets is encountered. 
     
     
         18 . A method for acquiring seismic data with varying illumination and/or resolution, the method comprising:
 driving a plurality of autonomous underwater vehicles (AUVs), each having a seismic sensor;   towing with a source vessel a source;   navigating with an AUV of the plurality of AUVs along an AUV sail line; and   navigating with the source vessel along a source sail line,   wherein the source sail line is calculated based on a set of naturally different regions and/or humanly set targets that characterize a region to be surveyed.   
     
     
         19 . The method of  claim 18 , wherein the AUV and the source vessel dynamically change an offset distance between them, while sailing during a seismic survey, based on the naturally different regions and/or humanly set targets. 
     
     
         20 . The method of  claim 18 , wherein the offset distance changes to achieve a better illumination and/or resolution.