【摘要】 将过井地震层析成像的级连算法应用到垦71区井间地震资料处理中,得到了高分辨率、精确的井间纵波速度结构。首先根据初至出射角,旋转合成得到清晰的纵波波场,再精确拾取初至到时。初始速度模型是参考测井资料的分层模型,第一级反演算法为分辨率较低但稳定的BPT反演算法,为第二级高分辨率反演算法——阻尼LSQR迭代反演算法提供模型。层析结果显示出清晰的泥、砂互层,与测井参数构造解释对比,高、低速带与砂/泥岩层基本吻合,最高能分辨1/4地震波波长的薄层。研究证明级连算法能很好地兼顾高分辨率和高精度,大大提高了井间地震走时层析成像的质量,可以广泛地应用于油田的勘探和检测。更多还原

【Abstract】 We apply cross-hole seismic tomography cascade algorithms to obtain accurate and high resolution P wave velocity structure in Ken 71 block.At first,for precisely picking the first-arriving travel times,we compose the break first wave filed according to take off angle of receiver recording.And then,a multi-layered velocity is structured consisted with well sonic logs as the starting model.Finally,we perform cascade algorithms.This method is characterized by the idea of successive approximation from low to high resolutions.The BPT algorithm of low resolution and stability was used first to provide initial earth model for higher resolution algorithm: improved algorithm of LSQR with damping iterations.The high resolution tomography results are matched well with borehole logs,the distribution of the high/low velocity layers in tomography image are consistent with the location of sand/mud layers which are predicted from the borehole logs.The result can image sand-mud interbed with layers 1/4 wavelength.The research shows that cascade algorithms simultaneously considers the high resolution and accuracy of tomography and can significantly improve the quality of crosswell traveltime tomography.So this method could be widely used in exploration and monitoring of oil fields.更多还原