复杂河流相储层内夹层识别方法及其应用

Method of interlayer identification in complex fluvial facies reservoir and its application

复杂河流相储层研究难点为储层内夹层的识别。分析了频率对地震波形特征的影响,将夹层按地震反射波频率段分为3种类型,分别总结了利用地震波形特征识别夹层的方法:第1类,地震反射波频率略低于夹层识别最佳频率段,通过地震波形偏移、地震复波、地震振幅变化识别;第2类,地震反射波频率位于夹层识别最佳频率段,通过明显地震反射轴识别;第3类,地震反射波频率略高于夹层识别最佳频率段,通过分析夹层的有效地震反射贡献量识别。同时发现,地震波形偏移和振幅突变处一般为夹层发育的起始点,稳定地震复波对应夹层稳定发育区。利用地震波形特征识别复杂河流相储层内夹层的方法在Q油田实际应用中取得了良好效果,有效指导了该油田后续井的成功钻探。

Identifying the interlayers is difficult in complex fluvial facies reservoir. The effect of frequency on seismic waveform characteristics was analyzed, and the interlayers were classified into three types according to the seismic reflected wave frequency. Method of interlayer identification by seismic waveform characteristics was summarized. For the first class interlayer, the seismic reflected wave frequency is slightly lower than the best frequency of interlayer identification and it can be identified by seismic waveform migration, seismic repeat wave and seismic amplitude variation. For the second class interlayer, the seismic reflection wave frequency is in the best frequency of interlayer identification and it can be identified by obvious seismic reflection axis. For the third class interlayer, the seismic reflection wave frequency is slightly higher than the best frequency of in- terlayer identification and it can be identified by analyzing the contribution of the effective seismic reflection. Results show that seismic waveform migration and amplitude mutation are usually the indicators of the starting point of interlayer and stable seismic repeat wave is corresponding to the stable interlayer. The proposed meth- od of interlayer identification by seismic waveform characteristics in complex fluvial facies reservoir achieves a good result in Q oilfield and effectively guides well drilling.