3d Converted Wave Seismic Data Processing Application In BZ Area

When large-scale gas reservoirs are developed in the exploration area,gas migration pathways are dispersive and will affect the velocity of P-waves as revealed a special gas cloud phenomenon in the P-wave section,which makes it impossible to perform accurate gas cloud imaging.The velocity of the converted wave is not influenced by the gas cloud.Therefore,the advantage of the converted wave exploration is that the imaging accuracy in the gas cloud region is higher than that of the pure P wave.Converted wave surveying is usually shot by a P-wave source and received by a multi-component sensor and can obtain P-wave data and converted-wave data simultaneously.Converted wave processing have its particularity over P-wave processing.Due to the undulation of sea bottom and the randomness of the detector deploying,the detector will be inclined,and its azimuth will be deviated,causing the aliasing of P-and S-wave,which requires rotation processing.This paper adopts horizontal component rotation technique to separate the P-and S-wave data.Converted wave seismic signals have a low frequency and a low velocity,according to these special properties,the paper designs different filters in different domains to suppress the noise energy without damage of signals.In converted wave processing,due to the asymmetry of the ray path and the characteristics of frequency and wavelet,the parameters of amplitude compensation and deconvolution is also different from the P-wave processing.It is pivotal that the common conversion point gathering and velocity analysis in converted wave processing.The paper uses specified layer method to complete common conversion point gather sorting,and uses a combination of one-parameter and multi-parameter velocity analysis methods to establish and iterate converted wave velocity volume.To the converted wave imaging issue,this paper applies Kirchhoff PSTM of VTI bending ray method to acquire a good imaging result and analyzes it in a more step.Based on the experience of previous converted wave data processing,the research comprehensively studies the above processing methods.Considering the geological structure and the seismic data characteristics of the BZ area,we've precisely processed the seismic data in BZ area with appreciate method and suitable parameters,and the good imaging results have been achieved in the gas cloud area,which provide strong support for seismic geologic study in the region.