Abstract：The paper summed up the principle or method for using P-wave amplitude and velocity to detect fracture.The characters are to use periodic variance of P-wave amplitude and velocity with azimuth to evaluate the direction and density of fracture.But above-mentioned methods have advantages and disadvantages respective-1Y.RVA(Reflection amplitude Variation with Azimuth)can reflect thin-layer char- acter but affected by noises seriously;VVA(Velocity Variation with Azimuth)is stable but only can identity a large suite of reservoir and has inaccurate resolution for identifying thin-reservoir.Because ofthat,the paper presented a new method for using Impedance Variation with Azimuth(IPVA)to detect fracture.The basis of principle is"Because of velocity being a cosine function of azimuth in anisotropic medium,the impedance is certainly a cosine function of azimuth".Combining with seismic-geologic character of fractured shale in Luojia area,the full-azimuth 3D geometry with brick style in piece(10 lines,256 shots) is designed in the paper;on the basis of processing of high-fidelity,arnplitude and surface-consistence for 3D data,the super CMP gathers with 512 fold have been formed after enlarging bin to original CMP gathers with 64 fold;velocity analysis,NMO correction,amplitude labeling,azirnuth AVO stack,azimuth impedance inversion,VVA(RVA) and analysis of IPVA fracture attribution are conducted to 9 azimuth gathers respectively. Application results shows that the IPVA has stable solution and high resolution comparing with RVA(VVA).
