【摘要】 川西坳陷DY构造是川西深层须家河组勘探和开发的重点区块,目前已完钻5口井,测试显示该区块具有较好的勘探和开发潜力。为了更好地进行下一步勘探和开发工作,目前亟须查明该地区须家河组砂体的空间展布特征。通过对地震反演方法的比较认为,基于统计学的概率密度函数随机地震反演方法是DY构造现阶段最佳的地震反演方法。该方法将地震随机反演与地质统计有机结合,充分考虑了地下介质的随机特性,使反演结果更符合实际地质情况,且分辨率较高,解决了基于模型反演方法对井的依赖性较强、未考虑地下介质的随机特性、模型化严重、多解性较强等问题。在统计和分析测井资料所反映的地球物理特征的基础上,认为该地区仅利用速度反演就能够很好地得到砂体的空间展布特征,但是进一步区分有利砂体和干层的效果较差。采用基于统计学的概率密度函数随机地震反演方法,对川西坳陷DY构造须家河组的砂体进行了预测,预测结果与实际钻井结果吻合较好,为该地区下一步勘探和开发提供了依据。更多还原

【Abstract】 DY structure of Western Sichuan Depression is the main area for the exploration and development of deep Xujiahe Formation. Five wells have been drilled,and well testing shows that the block is a potential area.In order to better carry out exploration and development for the next step,we need to investigate the spatial distribution characteristics of sand bodies of Xujiahe Formation in the block.Comparison by using seismic inversion methods indicates that stochastic seismic inversion method based on statistical probability density function is the best method appropriated for DY structure in present.The method gives enough consideration to the random characteristics of subsurface geologic bodies,to make the inversion results be more suitable to the actual conditions and be higher in resolution.Further,this method has overcome the problems caused by the model-based method,such as strong dependency on wells,without consideration on the random characteristics of subsurface geologic bodies,serious modeling degree and ambiguity, etc.Based on the statistics and analysis on the geophysical characteristics reflected by log data,we found that the spatial distribution feature of sandbodies can be well achieved only by using velocity inversion in the area,but it is difficult to further distinguish sandbodies and dry layer.The stochastic seismic inversion method was applied to predict the sandbodies of Xujiahe Formation in the area. The prediction result is accord with actual drilling data,which provides basis for further exploration and development.更多还原