P-wave fracture prediction algorithm using pre-stack data with limited azimuth distribution: A case study in the TZ45 area, Tarim Basin, China

Fractured reservoirs always show anisotropic amplitude features, i.e. the reflection amplitude of seismic waves varies with offset and azimuth (AVOZ). A noise attenuation fracture inversion algorithm is presented for fracture detection based on P-wave AVOZ. The conventional inversion method always fails when applied to limited azimuth data because of the existence of noise. In our inversion algorithm, special attention is paid to suppressing the noise during inversion, to overcome the limitation of the conventional inversion method on limited azimuth data. Numerical models are employed to illustrate the effectiveness of the method. The inversion algorithm is then applied to Tazhong 45 area field data which is acquired under limited azimuth distribution. Compared with cores and fullbore formation microimage (FMI), the inverted results (fracture density and orientation) are reasonable, suggesting that the inversion algorithm is feasible for fracture prediction in the Tarim Basin.