Abstract: In order to resolve the difficulties in identifying the fractures in horizontal wells,the method of identifying fractures with acoustic variable density log (VDL) data has been studied.VDL simulation tests have been conducted to find the VDL response to fractures in horizontal wells,and then VDL data acquired before and after actual fracturing was used to identify the fracturing section and evaluate the results.Research results showed that when the casing wave amplitude is low,and formation wave amplitude high in non-fracture section when first and second interface have a good cement bond,with thick and clear VDL plots.With an increase of fracture number between receiving and launching detectors at fracturing interval,amplitude of casing wave was increased,and formation wave amplitude was decreased.While formation wave in VDL plot was fuzzy white grayish,with large curvature and V-shape.At the same time,formation compressional wave time difference was increased and energy reduced.Both simulation test and field application indicated that the VDL could be used to identify transverse fractures in horizontal wells,which can provide a basis for the identification of fractures and an assessment of fracturing effects in horizontal wells.