Attribute Analysis Of Survey Design
The survey design is not complete until the attributes are analyzed. The attributes can only be analyzed in detail by computer software. Obstacle effects on design, in particular, cannot be assessed by hand or observation. There are many attributes of interest but some are considered standard to any 3-D survey.
The standard attributes analyzed for each bin are:
Depth point coverage-The subsurface coverage of depth points achieved by the survey. The display is the bins that contain a geometric midpoint.
Fold-The number of traces whose depth point falls within the bin are shown for each bin.
Offset ranges--The distribution of the source-receiver distances in the bin to show if some range of distances is missing.
Azimuthal distribution-The range of source-receiver directions for the traces in each bin is calculated and displayed.
Costs-Cost is an attribute that can be estimated by the statistics of the survey design such as the total number of stations. The cost of the survey may well be the attribute requiring iterative design.
Obstacles should be defined before the analyses are made to include the effect of the missing source and receiver stations. The obstacle effects may require a change in the survey design or just some additional stations.
With thousands of bins in most surveys, the display of the attributes often requires color displays to be visible to the designer. These color displays also allow combinations of attributes such as azimuth and offset.
Attribute analysis can be extended to include the suitability