裂缝性碳酸盐岩储层声波时差曲线的波动和增幅分析

Analysis of Fluctuation and Amplitude Increase in Sonic Logs Caused by Fractures in Carbonate Rocks

研究了裂缝性碳酸盐岩储层声波时差曲线的波动和增幅现象，认为是裂缝对声波的衰减导致到达远接收器的初至波幅度降低，因而形成3～4μs／ft的时差增幅，从而有效解释了声波时差曲线的波动和增幅现象。利用成像资料和常规测井资料相结合，研究增幅发生条件和规律，发现低角度、较大开度的裂缝导致时差增幅。

Based on analysis of field logs, fluctuation and amplitude increase in sonic log caused by fractures in carbonate rocks are investigated. It is found that the attenuation of sonic waves by fractures leads to severe amplitude decrease at receivers far from the source. As a result, the travel time has an increase of 3-4 μs/ft. This attenuation mechanism successfully interprets the fluctuation and amplitude increase in sonic logs. Combined with electric and acoustical imaging logs, the conditions for the amplitude increase are investigated. The results show that fractures with lower angle and larger open-width lead to more significant increase in sonic logs.