川南页岩小微尺度断层井震结合识别方法研究

Small and micro-scale fault identification method based on well logging and seismic data in Southern Sichuan shale

川南页岩气地层钻井过程中频繁钻遇断层,对水平井施工影响极大。根据地震正演结果,大尺度断层可以通过常规地震剖面识别,但对于小尺度与微尺度断层则缺乏有效的分析手段。为此,优选基于倾角控制增强的最大似然属性分析方法,可以实现小尺度断层的识别,在采用伽马比值与元素三维显示图板开展微尺度断层识别的基础上,建立了小微尺度断层的识别流程和判别标准。井场应用结果表明,页岩气地层的小微尺度断层识别符合率达到83.33%,为水平井地质导向提供了判别依据和技术支持。

Frequent faults are encountered while drilling in the shale gas formation of Southern Sichuan,which has a great impact on the construction of horizontal wells.According to the results of seismic forward modeling,large-scale faults can be identified by conventional seismic profiles,but there is a lack of effective analysis methods for small-scale and micro-scale faults.The maximum likelihood attributes analysis method based on dip control enhancement is selected,which can realize the identification of small-scale faults.on the basis of micro-scale fault recognition by using gamma ratio and element 3D display plate,the recognition flow and discrimination standard of small and micro-scale faults are established.The results of well site application show that the coincidence rate of small and micro-scale fault identification in shale gas formation is up to 83.33%,which provides discrimination basis and technical support for geological steering of horizontal wells.