Qseabed multicomponent system
The Qseabed system is a cabled multicomponent ocean-bottom seismic system with a global track record since 1999, which includes surveys in the North Sea, the Caribbean, Angola, the Mediterranean, and the Arabian Gulf. It is a single-sensor acquisition system with fully calibrated hydrophones and three-component (3C) accelerometers. This is complemented by unprecedented levels of positioning accuracy and industry-leading source options. Qseabed crews can record data from up to four cables, each with a maximum active length of 30km, and can operate in water depths up to 1500m. This supports flexible survey design options that improve efficiency and minimize the acquisition footprint on irregularly shaped surveys while maximizing the fold.
Today the Qseabed system is the system of choice for many operators acquiring multiple high quality 4D datasets. This proven system delivers reduced survey time, cost, and equipment exposure
Uniform seafloor coupling for improved wavefield fidelity
Poor seafloor coupling with conventional seabed systems results in phase and frequency errors between the X and Y components. The unique Qseabed cable design enables uniform coupling in all directions, ensuring fidelity between all four wavefield components and enabling the highest quality fracture characterization.
Geophone accelerometer response increases bandwidth for better definition
The Qseabed vibration sensor is a fixed-axis geophone accelerometer (GAC) that converts surface displacement into an acceleration signal. The accelerometers are fixed within the sensor unit, the orientation of which is measured by inclinometers. This design eliminates the gimbal mounting and greatly improves signal fidelity.
The GAC offers a substantially improved response compared to a conventional geophone due to the removal of resonance and spurious frequency effects. The response is consistent over the useful seismic band from 1.5 Hz up. The dynamic range of the accelerometers at 2-ms recording is typically 136 dB. The GAC avoids the low-frequency resonance typical of conventional geophones and, therefore, provides a more repeatable low-frequency response, which significantly increases the useful bandwidth on the low end of the spectrum. This broader bandwidth contributes to better definition in the S-wave image.
Calibrated hydrophones offer better amplitude stability
The Qseabed system technology automatically calibrates the hydrophones, thereby reducing sensitivity variations that introduce perturbations and noise. Qseabed system hydrophones give better amplitude stability, both in the field and in the processed data. They also have much higher survival-depth tolerances than conventional hydrophones and avoid degraded sensitivity over time or sensor destruction due to hydrostatic pressure.
Integrated positioning promotes safe, efficient, and high-quality acquisition
The Qseabed system uses intrinsic ranging by modulated acoustics (IRMA) transducers in the cable for acoustic positioning. The hydrophones are also used for positioning, thus improving safety, efficiency, and quality. Accurate positions for every receiver are obtained in parallel with acquisition, without applying offsets, and with no externally mounted devices on the cable. Deployment/retrieval operations are safer and more efficient.
Responsive real-time survey control
The TRINAV TRILOGY integrated navigation and positioning system module handles the survey’s navigation and positioning data, facilitating real-time control of operations with multiple recording and shooting vessels, enabling safe and efficient operations.
Improved source signal reduces survey time
Qseabed system source vessels have an advanced digital source controller that provides a fully calibrated source signature for each shot utilizing the notional source method. This accounts for variations in the signature of the airgun source from shot to shot (caused by gun dropouts and array movement), increasing data accuracy, consistency and repeatability. Source signature deconvolution is used to recover shots discarded due to traditional dropout criteria, thereby reducing project time. The TRISOR TRILOGY acoustic source control element of the Qseabed system also enables compensation for systematic signature variations when surveys are reacquired with a different vessel or different arrays.