Key preprocessing technology for CBM AVO analysis

The hazard of amplitude versus offset (AVO) analysis for coalbed methane (CBM) mainly comes from amplitude modifications during seismic preprocessing that is nevertheless necessary for high signal-to-noise of ratio (SNR), high resolution, and high fidelity, and yet exhibits a favorable or unfavorable possibility to implement CBM AVO analysis.Similar to sandstone gas reservoir, AVO preprocessing for CBM reservoir should abide by a relative amplitude preserved (RAP) principle and additionally emphasize differences on the class IV AVO anomaly.As for dealing with linear noise attenuation, near surface variety compensation and spatial imaging, the key technologies adapted to CBM AVO preprocessing include radial trace (RT) filter, high-low frequency surface-consistent amplitude compensation (SCAC), and RAP Kirchhoff pre-stack time migration (PSTM).A real 3D data demonstrates that the key technologies compliant to RAP principle in CBM AVO preprocessing can preserve the class IV AVO anomaly and benefit CBM AVO analysis and improve CBM estimation.