GeoStreamer® – the Next Generation of Marine Seismic

Delivering high quality seismic data with enhanced resolution, better penetration and  improved multiple attenuation.

Unique GeoStreamer technology allows the recording of both pressure and velocity fields during marine seismic acquisition and in the quieter and operationally more efficient environment of a deeper tow than conventional. PGS patented processing of these wavefields then allows the separation of upgoing and downgoing signals and removal of the receiver ghost. The result is broadband seismic data capable of imaging deeper and more complex structures, and produce a clearer image capable of significantly reducing the uncertainty in exploration and development decisions.

The GeoStreamer® completely removes the receiver ghost. The related seismic data is more reliable to interpret, and contains greater frequency bandwidth and greater signal-to-noise content than any other streamer technology or streamer configuration. This is true for all arrival times and depths, for all water depths, and for all geological settings.

Total pressure image from a conventional streamer (left) vs. the deghosted up-going image from the GeoStreamer (right).

Enhanced Resolution

The new GeoStreamer records both pressure and the vertical component of the particle velocity. Separation into up-going and down-going pressure and velocity wavefields is straightforward. Thus, the receiver ghost can be removed from the pressure wavefield, increasing resolution. Both the lower and higher frequency content is substantially boosted in comparison to conventional pressure-only streamer data. Significantly, the signal-to-noise ratio for all frequencies is also boosted, particularly for marginal conditions. Dual-sensor streamer data provide the optimum platform for spectral enhancement processing to recover high frequencies lost by natural attenuation in the earth, for inversion to acoustic and elastic impedance, for 4D survey matching, and for advanced noise and multiple removal.

Superimposed amplitude spectra for pressure (blue), velocity (red), and the deghosted result (black).	Improvement in frequency content for deghosted pressure data vs. total (conventional) pressure data.

   

Better Penetration 

Every recorded and processed reflection wavelet from conventional marine streamers is accompanied by a ghost reflection from the ocean’s surface. The resulting filter effect on the recorded data restricts streamer towing depths to a range of about six to nine meters. The new streamer is typically towed at a depth of 15m in a quiet and stable environment. Towing deep coupled with receiver deghosting provides a significant boost to low frequency amplitudes and signal-to-noise ratio. Deep signal penetration is greatly improved, creating opportunities for subsalt and sub-basalt imaging, and deep target imaging in general.  

Data comparison for a window 6 s TWT below the water bottom. Total pressure image from a conventional streamer (left) vs. the deghosted up-going image from a dual-sensor streamer (right). 

 

Better Multiple Removal

An advanced implementation of Surface Related Multiple Elimination (SRME) is possible with the new streamer. Multiple prediction is based on the up-going pressure wavefield and the down-going velocity wavefield. The key advantage of using the down-going velocity wavefield is that any variations in the sea surface level and reflection coefficient are implicitly included in the implementation. In addition, the use of a velocity field automatically incorporates angle-dependent scaling into the prediction process.

Total pressure image from a conventional streamer with conventional SRME applied (left) vs. the deghosted up-going image from a dual-sensor streamer with dual-sensor SRME  applied (right).

Improved Operational Efficiency

GeoStreamer® operations exist in a longer weather window, sometimes in scenarios where conventional operations would be shut down. Efficient acquisition follows from only having to tow all streamers at one depth, exploiting the full streamer width capacity of the vessel, and easily controlling all streamer behaviour. Operations for streamer deployment, towing and recovery are conventional, thereby reducing risk and improving reliability.

Towing deep in a quiet environment with collocated pressure and velocity sensors improves operational performance and efficiency.