利用地震岩性反演技术进行储层预测及效果分析

Application of seismic lithologic inversion technology for reservoir prediction and its effect analysis

砂西N1-N21油藏呈现多而薄的特征,常规地震反演方法进行储层预测比较困难。采用基于模型的反演方法,较常规反演方法能达到较为理想的纵向分辨率,利用测井的高频和低频成分来弥补地震有限带宽的不足。从地质模型出发,用已知的地质信息和测井资料作为约束条件,采用模型优选迭代扰动算法,对测井资料进行内插外推,不断修改地质模型,使合成地震记录与实际地震数据最佳吻合,在理论上反演可以得到与测井资料相当分辨率的反演数据体,从而推算出较高分辨率的地层岩性数据。在反演数据体上精确对比追踪砂层的顶底包络面,制作时间厚度图,根据各井声波时差曲线反算出的层速度,制作该砂层的厚度分布图,取得了可信度较高的储层预测结果。

The N1-N21 reservoir of Shaxi area is characterized by multiple and thin, so the conventional seismic inversion method for reservoir prediction is very difficult. Compared with the conventional inversion method, this method based on the model can achieve more ideal vertical resolution. Te logging of high frequency and low frequency component was used to make up for the inadequacy of the limit- ed seismic bandwidth. Starting from the geological model, using the known geological information and logging data as constraints, and a- dopts the model of optimizing iterative perturbation algorithm which can realize interpolation and extrapolation of logging data and con- stantly modify geological model to make synthetic seismogram and actual seismic data achieve the best match. In theory, the lithologieal inversion for the resolution of the inversion data volume and the resolution of the logging data is the same, so as to calculate lithology da- ta of higher resolution. We can provide an effective basis for favorable reservoir prediction of Shaxi area by precisely tracking the top and bottom envelope of inversion data volume which can make time thickness map, through velocity calculated by the well acoustic time curve, thickness distribution can be obtained, and the result of prediction is believable.