井驱地震速度模型修正技术及其在随钻驱动处理中的应用

Correction method for well-driven seismic velocity model and its application in LWD processing

随钻驱动处理作为将地面地震资料应用于开发地震的有效方法,对规避钻井风险,提高钻井成功率具有现实意义。其中的核心问题是如何利用随钻资料便捷地提高地面地震速度模型的精度,从而提高地震资料成像精度,指导钻井轨迹调整。为此,提出井驱地震速度模型修正技术,即在传统叠前深度偏移速度模型基础上,将正钻井已钻地层的速度、深度信息作为约束,结合周围已钻井的测井、VSP资料快速修正现有地震速度模型,从而得到更精确的地下地震成像,实现对未钻遇地层的地质描述与预测,提高钻井成功率。油田应用实例表明,该方法缩短了速度模型更新迭代的时间,可满足随钻驱动处理对精度和时效性的需求,对于正钻井实时提高钻前预测精度具有重要作用。

As an effective method to apply surface seismic data to development seismology,loggingwhile-drilling(LMD)processing plays an important role in avoiding drilling risk and improving the drilling success rate.The core problem is how to use the measured data while drilling to improve the accuracy of the surface seismic velocity model and further promote the accuracy of seismic data imaging and guide the adjustment of drilling trajectories.Therefore,this paper proposed the correction method for the well-driven seismic velocity model.Specifically,given the traditional pre-stack depth migration velocity model,we presume the velocity and depth information of the drilled formations while drilling as constraints and rapidly correct the existing seismic velocity model combined with the logging and VSP data of drilled wells in the surrounding area.In this way,more accurate seismic underground imaging can be obtained,and the geological description and prediction of the undrilled formations can be realized to improve the drilling success rate.Oilfield examples show that this method shortens the update and iteration time of the velocity model and can meet the accuracy and timeliness requirements of LWD processing.The proposed method plays an important role in improving the accuracy of real-time pre-drilling prediction while drilling.