Near Trace Cube and Shooting Navigation

The SeisNav Resolve™ 'Near Trace Cube' and 'Shooting Navigation' software has been used to QC 3D seismic data totaling more than 200,000 CMP Kms.

This successful package consistently identifies problems with navigation and seismic data. Data may be checked in the field or in-house by merging the seismic single traces with the field or processed navigation data. Problem data sets can be identified before they can make an impact on production or 3D bin coverage requirements.

• Errors detected using the 'Near Trace Cube' and 'Shooting Navigation' tools include:
• Source/Receiver positioning errors
• Gun flag reversals
• Over smoothing of field/processed data
• Incorrect acoustic/steamer definitions
• Shift in source array centers
• Incorrect laybacks to center source
• Erroneous P190/P184 generation
• Unacceptable radio navigation
• Seismic timing errors
• Two boat timing

Shooting Nav Display of streamer data

Resolve Merge

SeisNav Resolve has extensive merging capabilities including:

• Merging navigation and survey coordinates into the headers of a seismic SEG Y file
• Matched file merge (P1/84, P1/90, SPS)
• Unmatched file merge (SEG P1) using Excel™ to input match. Digital observer logs created by other systems are easy to convert.
• Nonstandard merges can use any collection of ASCII files. Single record digital observer logs can input directly and can specify merge of any combination of coordinate files.
• SEG D tape input in flow with inline merge.
• Tape to tape merge.
• Merge basedc on SEG D time stamp and the nearest navigation file time stamp. These can be adjusted by any constant amount.
• Time stamp merge. The most recently surveyed coordinate as of the time of the shot will be used allowing receivers to move over time.
• Automatic binning to a prospect definition during merge allows collection of important inline and crossline gathers.
• Flow creation with 'Inline Merge' processor. Allowing different groups of traces to be output to different files, or any header manipulation desired.
• Input of P1/84 and P1/90 compressed files. Compression can reduce file sizes by up to 75:1.

The Resolve merges have proven themselves to be fully scalable processors capable of handling both small and large jobs with ease. SeisNav Resolve™ has been used both for merging near traces in deep water marine surveys and merging full shot records in large land and OBC jobs.

The output from the merge, like all Resolve SEG Y files, is ready for import into other processing systems such as ProMax™.

Geometry QC

The primary goal of SeisNav Resolve's Geometry QC package is to ensure that source and receiver coordinates are accurate and consistent with the seismic data. This can be performed real-time, or after the survey is complete. If performed real-time, all bad points discovered using the system may be re-surveyed in the field (if possible). If performed after completion, Resolve can create an approximation of the actual position. Results from all tasks can be displayed in the Resolve displays to depict problems and/or solutions.

Superior Geometry QC results are achieved by using the seismic data with the navigation data. An important benefit of using the seismic data is that all coordinates used will be merged into the headers of the SEG Y files. These can be output to tape for a head start on processing.

• Resolve's Geometry QC features include:
• Comparison of field coordinate sets, e.g. computed vs. preplot or acoustic vs. first break.
• Map of coordinates overlaid on a topography map (if available).
• Separate coordinate displays verifying the consistency between source and receiver elevations.
• Merging coordinates into the headers of the seismic data.
• '2D Edit Display' can be used to view seismic with computed first break times overlaid and LMO flat plots.
• 'Shooting Nav' display allows viewing of geometry and seismic on the same screen.
• 'Residual Navigation' process for batch first break picking and coordinate computation.
• 'Geometry Workshop' for visual batch and interactive coordinate computation and first break picking.
• Near trace cube verifying coordinate consistency.
• 3D stack further verifying coordinate consistency with the seismic.
• Creation of new survey/navigation files.

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