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Combining wavelet transforms with conventional log differential curves is used to identify fractured sections is a new idea. In this paper, we fi rst compute the mother wavelet transform of conventional logs and the wavelet decomposed signals are compared with fractures identified from image logs to determine the fracture-matched mother wavelet. Then the mother wavelet-based decomposed signal combined with the differential curves of conventional well logs create a fracture indicator curve, identifying the fractured zone. Finally the fracture density can be precisely evaluated by the linear relationship of the indicator curve and image log fracture density. This method has been successfully used to evaluate igneous reservoir fractures in the southern Songnan basin and the calculated density from the indicator curve and density from image logs are both basically consistent.

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