Abstract: The carbonate reservoir in the Niudong buried hill are mainly fracture-cave reservoirs, with strong heterogeneity and rapid lateral change. The prediction accuracy of cracks by conventional seismic attribute analysis methods is low due to the obvious attenuation of amplitude, frequency and velocity affected by the cracks. As a result, fracture prediction of azimuthal anisotropy is carried out in this area as the accurate identification of fracture reservoirs is the key to the hydrocarbon exploration. The results of imaging logging show that steep fractures are mainly developed in the study area, which has the characteristics of HTI medium. The azimuth angle dataset is obtained by determining the offset range and dividing the four azimuth ranges, which based on the forward modeling carrying out on the longitudinal wave reflection coefficient formula. The main direction of the fracture in the study area is determined to be NE by outlining the fracture development zone combined with the orientation and density of the features, which are calculated by azimuth seismic attributes of longitudinal wave extracted by the data volume. It is proved that AVAz technology has a good practical application value for reservoir prediction of high and steep fractures in carbonate reservoir by the use of imaging logging data in actual drilling, which verified the prediction results, and obtained a good match.

Key words: carbonate rock, HTI medium, azimuth anisotropy, AVAz technique, fracture detection