Bandwidth Controlled Sources and OBN MEMS – A Perfect Symbiosis in Seismic Surveying

SUMMARY

MEMS (Micro-Electro-Mechanical Systems) -based sensors, initially introduced in seismic streamers, are now also used in Ocean Bottom Nodes (OBN) for benefits such as flat amplitude and phase spectra across the seismic bandwidth, high vector fidelity, low power consumption and more.

MEMS measure acceleration and are by design without gain settings making the topic of sensor saturation and its effects important to consider. Any sensor exposed to signal exceeding its maximum scale will exhibit some form of saturation effects. In the case of MEMS one may experience clean clipping or a wavefield perturbation of short duration.

This paper demonstrates that source energy beyond the seismic bandwidth can saturate sensors, particularly in shallow waters or with large source volumes, and explores how bandwidth-controlled sources can delay saturation and maximize MEMS sensor performance. Field trials in the North Sea confirm that such sources allow for higher source volumes without compromising data quality, particularly for near-offset recordings.

Hydrophones, geophones, DAS, and other rate-of-change sensors benefit from these findings too, as they allow us to maximize dynamic range utilization and enable gain settings with lower noise floors. Moreover, a reduced high-frequency output aligns with environmental goals by minimizing the seismic source’s sound footprint
supporting sustainability