滚动扩边稀井区的沉积微相刻画方法研究

Study on Sedimentary Microfacies Characterization Method in Sparse Well Block with Progressive Extension

针对开发区周边稀井区井控程度低,沉积刻画精度与已开发区存在较大差距的问题,分析不同沉积微相在砂岩厚度、地震波阻抗等方面存在的差异,统计开发区不同沉积微相的砂岩参数,建立不同微相所对应的砂岩数据库;以地震属性预测的平面上扇体展布控制规模为基础,通过微相知识库分析地震反演所表征的稀井区沉积砂体发育特征,确定砂体的微相类型;从顺物源、垂直物源砂体延伸规模作为微相展布范围,实现稀井区沉积微相的定量刻画。研究表明:通过A区块密井网区辫状河三角洲微相的单砂体厚度、累积概率、反演的波阻抗值等参数可有效表征不同沉积微相砂体发育特征,其中,水下分流河道和河口坝在砂岩参数上具有明显的优势;建立沉积微相知识库结合地震属性预测的稀井区沉积微相刻画方法可以有效提高稀井区沉积微相刻画精度,符合率达到91%,稀井区有利沉积微相类型主要富集在A5和A02等井区。研究成果应用于A区块周边的稀井区滚动评价部署及方案部署,取得较好效果,累计建成产能2.35×10^(4)t,提交探明储量超过200×10^(4)t。研究成果可为老油田稳产增产提供有力支撑。

In view of the low degree of well control in the sparse well block around the development area and the great gap between the accuracy of sediment characterization and the existing development area,the differences were analyzed in sandstone thickness and seismic impedance of different sedimentary microfacies,the statistics was made for the sandstone parameters of different sedimentary microfacies in the development area,and the sandstone database was established in correspondence to different microfacies;based on the control range of fan spreading on the plane predicted by seismic attributes,the development characteristics of sedimentary sand bodies in sparse well block characterized by seismic inversion were analyzed by microfacies knowledge base,and the microfacies types of sand bodies were determined;the quantitative characterization of sedimentary microfacies in sparse well block can be implemented by taking the extension range of sand bodies parallel and vertical to sediment origins as microfacies distribution range.The study shows that The development characteristics of sand bodies in different sedimentary microfacies can be effectively characterized by single sand body thickness,cumulative probability,inverse wave impedance and other parameters of braided river delta microfacies in the dense well pattern area of Block A,among which underwater distributary channel and channel mouth bar were obviously advantaged in sandstone parameters.The microfacies characterization method based on the microfacies knowledge base and seismic attribute prediction can effectively improve the accuracy of sedimentary microfacies characterization in the sparse well block,with a coincidence rate up to 91%.The favorable microfacies types in the sparse well block are mainly distributed in Well Blocks A5 and A02.The study results have been applied to the evaluation,deployment and scheme implementation of sparse well block with progressive extension around Block A,and achieved excellent results,with a cumulative production capacity of 2.35×10^(4)t and proved reserves of 200×10^(4)t.The study results provide strong support for stimulation and stable production of old oilfields.