Application of OBN Wavefield Separation in an Exploration Area of East China Sea

Deghost and frequency-broadening processing have always been important research contents of high-resolution imaging in exploration area of East China Sea. In order to obtain high-resolution and broadband seismic data, the new ocean bottom nodes (OBN) seismic data in this area is used to attenuate all downgoing ghosts on the receiving side and broaden the frequency band by adding the P-component and the Z-component data based on the polarity difference in the seismic wave response between the P-component hydrophones and the Z-component geophones. However, due to differences in instrument sensitivity and coupling with the seabed, the P component and Z component data are inconsistent in amplitude, frequency, and phase, making direct addition of the two components is impossible. Calibration is therefore essential for accurate wavefield separation. In this paper, the cross-ghost method is used to calibrate P and Z component. The ghost of P component is added to the Z component and the ghost of the Z component is added to the P component, respectively. Therefore, the P and Z component is calibrated in amplitude, frequency and phase. This method broadens the bandwidth of seismic data in an exploration area of East China Sea, increases the accuracy of seismic imaging, and provides important information for trap description and reservior prediction in this area.