变窗长阵列声波测井波形处理与换能器的振动模态

Waveform of window-variant array sonic log and vibration mode of transducer

1. 中原油田测井公司数控测井中心,河南濮阳 457001;2. 天津大学,天津 300072;3. 天达腾飞公司,天津 300072;4. 吉林油田测井公司,吉林松原 131000

Well Logging Company, Zhongyuan Oilfield Company, Puyang 457001, China

声波换能器振动时具有不同的振动模态,分别对应于不同的频率特征,换能器发射或接收声波时,在这些振动模态的频率附近灵敏度最高。裸眼和套管井对声波有过滤作用,不同频率的传播特征不一样,这些影响使得实际测量的阵列声波测井波形的频率呈一定的分布特征。裸眼井测井波形中,纵波、横波和伪瑞利波、Stone-ley波的传播速度不同,频率分布也有一定的差别。根据这些特点和声波换能器频率特征测量结果,设计了变窗长处理软件,针对实际测量波形中不同类型的声波特征,使用不同的窗长进行处理,有效地提高了声波时差的处理精度。

Transducer works at several modes of vibration, each of which corresponds to a specific frequency. Transducer is most sensitive around the frequency of vibration mode when the transducer emits or receives acoustic waves. Uncased hole and cased hole impose filtration at acoustic waves, leading to waves behavior differently at various frequencies. The observed waveform of array sonic log is in specific frequency characteristics. As far as the waveform of sonic log from uncased hole is concerned, waves like P-waves, S-waves, pseudo-Rayleigh waves, and Stoneley waves travel with different velocity and frequency. Based on these observations and the frequency characters of transducer, new software was developed. Processing sonic waves of different characters with variable win-dows can effectively enhance the precision of interval transit time.