GNS™ acquisition technology


The GNS™ 3D 4C offshore acquisition technology with Autonomous Self Pop-up Nodes (SPNs) offers the same performance as conventional towed-streamer acquisition, while significantly reducing acquisition costs and providing better imaging results.


How does it work?


There are two vessels involved in acquisition operations. The first one is a shooting vessel, and second one is an SPN vessel used for SPN operations (initial deployment, recovery, data copying and QC and re-deployment). Recent advancements in Information Technology made it possible to develop the SPNs that can be re-deployed without delays, ensuring non-stop operations of the shooting vessel. The performance rate of GNS™ technology is comparable to the traditional towed streamer acquisition. However, the daily rate of both vessels (shooting vessel and SPN vessel) is far less than the daily rate of one multi-streamer 3D vessel for conventional marine operations.


Geophysical advantages

  • Recording units have no connection with the sea surface, which ensures quiet ambient environment, no tow noise and lower source generated noise;
  • Ability to acquire data in transit zones and in the areas with surface obstacles;
  • Four-component recorders receive seismic energy from all directions and provides seismic imaging in P-waves (compressional), PS-waves (converted), which provides significant advantages for:
    • Imaging of reservoirs seismically transparent to P-waves yet evident in S- wave image;
    • High quality P-S wave images of gas-charged reservoirs, not visible in PP-waves. S-waves do not propagate through water layer, and towed streamers record weaken double mode-converted P-S-P reflections;
    • Reservoir properties evaluation using such attributes as Vp/Vs ratio;
    • P-S-waves provide an additional tool to assess the azimuthal anisotropy for improved production through better characterization of complex fractured reservoirs;
    • Full-azimuth illumination of the survey target.
  • The offset range of acquired data is not limited and could be chosen according to local geological objectives;
  • Down-going and up-coming energy separation by hydrophone and vertical geophone component stacking is an effective tool for all receiver side surface related multiples suppression.

Operational advantages:

  • No need for specially equipped towed streamer seismic vessel;
  • Less exposed to weather-related risks and technological hazards, including areas of shallow water, obstructed and high-traffic areas, etc.;
  • No depth limits: the same instrumentation is used in deep sea, shallow sea, and in transit zones;
  • Excellent repeatability for time-lapse surveys;
  • Passive seismic reservoir monitoring and micro-seismicity study is made with the same equipment;
  • Acquisition of passive seismic data for direct hydrocarbon detection during active seismic acquisition operations.

Economic advantages:

  • Less costs of outboard equipment – less investment cost and shorter timing for survey mobilization;
  • Fast and easy replacement of failed seismic nodes;
  • Reduced cost of data with better data quality and full-azimuth wavefield recording;
  • Reduction of acquisition costs:
    • In comparison with 3D towed streamer survey – 30% less;
    • In comparison with 3D OBC survey – three to four times less;
    • In comparison with ROV – deployed 3D seabottom node surveys - ten times less.