Improved Imaging and Velocity Estimation
If velocities are not accurately established, this noise can leak through to the final seismic image, reducing resolution and the delineation of reservoir geology.
Early-stage velocity model building progresses faster and with greater confidence when more reliable low frequency information is present in the data, as this enables better discrimination and removal of multiples, and the construction of higher quality seismic images.
Modern high precision velocity model building techniques such as Full Waveform Inversion (FWI) require data that is rich in very low frequencies and low wavenumbers in order to work successfully. This is an excellent match with the characteristics of GeoStreamer® seismic.
Example of improved velocity estimation using Full Waveform Inversion (FWI) techniques that benefit from the richer content of low frequencies in deep-tow GeoStreamer data.
Better Interpretability and Reservoir Characterization
Richer low frequency content also reduces the presence of so called sidelobes. This increases the resolution of the data and its interpretability. One of the most important benefits of the additional low frequency content in GeoStreamer data is the ability to derive more reliable rock and elastic properties.
For conventional, band-limited seismic data geoscientists need to constrain the number of possible solutions when inverting for rock properties. Normally, this is done by injecting known or "a priori" information into the inversion model, using nearby well data or other geological information. As a consequence, the uncertainty of the inversion results away from these constraints increases rapidly.
Using GeoStreamer deep tow data, with its broader frequency content, substantially reduces the amount and potential bias of a priori data input. This makes the inversion or any quantitative interpretation solution less dependent on perceptions and assumptions, and increases its usefulness in areas where a priori information, such as well control, may be scarce or uncertain.
Comparison of relative acoustic impedance estimates from conventional data (top) and GeoStreamer (bottom). Well log information is display for reference with gamma ray logs in the upper panel and Ip logs in the lower panel.
GeoStreamer data shows much better match with well derived impedance value and a better correlation between the high impedance sands and the structural interpretation performed using the gamma ray log information.