4D (Time Lapse)

PGS believes that the foundation to any seismic experiment is a complete knowledge of all physical phenomena involved:

• The capability must exist to model all aspects of the seismic experiment.  PGS achieves this with the Nucleus^TM modeling package
• Quality control (QC) of all acquisition and processing steps must be a rigorous discipline, ideally performed in real-time, as events happen.   PGS achieves this with the onboard gAS-VIPER QC and recording system on all streamer and seafloor seismic vessels, linked in real-time by satellite telemetry to onshore installations
• QC must be multi-disciplinary, assimilating several seismic attributes and data types, thereby providing the most information possible during any decision-making process.   PGS achieves this by using the holoSeis^TM visualization system, integrated with the Nucleus^TM modelling package and the CubeManager^TM processing package, to seamlessly share modelling, operation, and processing data
• Several dedicated QC routines have been developed within CubeManager^TM to address operational QC and time-lapse 4D QC

Naturally, the acquisition technologies used must provide the optimal platform for any seismic data applications or studies.

Notably, PGS has developed the HD3D suite of data products to address the fundamental requirements of the ultimate seismic experiment, complemented by sophisticated pre-survey planning, 3D processing, and immersive visualization:

• Tight 3D spatial sampling of the recorded seismic wavefield
• Proper seismic illumination of the target geology

If these two objectives are satisfied, then any 3D seismic experiment will provide the optimal platform for any applications in processing and data analysis.   Therefore, HD3D represents the ultimate seismic experiment, capable of delivering a superior data product.

PGS delivers HD3D in a highly competitive manner because PGS has the most efficient and flexible acquisition technologies of any seismic operator. 

With regard to the delivery of 4D data with optimal repeatability between successive Base and Monitor surveys, PGS has introduced the following robust and proven strategy:

• Acquire the Monitor surveys so that each shot position in the Base survey is repeated.   This approach provides a first order improvement in the match in source-receiver azimuths (and therefore, a match or "repeatability" in amplitudes) between Base and Monitor surveys
  • Deploy additional streamers for a given sail line separation, so that an "overlap" of streamers is available at each sail line boundary.   This surplus of data provides significant benefits for processing, and greatly improves survey efficiency by reducing the requirement for "infill" lines
  • Use a HD3D strategy to provide optimal 3D spatial sampling of the seismic wavefield, and each source-receiver azimuth can be closely matched between Base and Monitor surveys
• Apply a sophisticed data processing approach to exploit the HD3D + overlap benefits to the data volume

Supported by near real-time 4D project management and QC capabilities, PGS believes it delivers the best 4D data products, using the most robust and transparent technologies available to the industry.

Ongoing R&D efforts are addressing each component in the QC and processing platforms described above.