四川盆地元坝地区茅口组台缘浅滩相储层物理模型

Seismic physical model of the Maokou Formation reservoirs of platform-margin shoal in Yuanba area,Sichuan Basin

四川盆地元坝地区元坝7井在茅口组钻遇台缘浅滩储层并获得高产工业气流,取得了油气勘探新领域的重大突破。为进一步落实台缘浅滩储层地震响应特征及其识别方法,根据该区地质地震综合解释成果,构建了与野外实际地层参数相近的三维台缘浅滩储层物理模型。按照实际地震资料采集与处理流程对模型进行了实验室物理模型数据采集与处理,得到了与实际野外地震响应特征相符的物理模拟数据。在此基础上分析了储层地震响应特征及其识别方法。研究结果表明:针对台缘浅滩储层基于大时窗的地震属性分析技术不能准确刻画沉积微相的变化,而依据地质模型精细解释层位和聚焦储层,能够更好的刻画地震相带;储层发育程度影响地震振幅,储层沉积厚度大、物性好,波峰能量强;振幅类属性能够直观的识别浅滩储层发育程度,而频率属性对储层边界识别能力强。

Shoal reservoirs were encountered by Well Yuanba-7 and yielded high industrial gas flow from the Maokou Formation at the platform margins of Yuanba area in Sichuan Basin,marking a major breakthrough in oil and gas exploration frontiers.In order to confirm the seismic response characteristics and identification methods of the reservoirs,the study constructed a three-dimensional physical model of platform-margin shoal reservoirs consistent with the actual formation parameters of the studied area based on the comprehensive geological and seismic interpretations.The model were then modified according to acquired seismic data and processing procedures to obtain physical simulation data for analyzing the seismic response characteristics and assessing prediction methods of the reservoirs.The results show that the seismic attribute analysis based on large time windows for platform-margin shoal reservoirs cannot accurately describe the changes of sedimentary microfacies.Instead,the fine interpretation of strata focusing on reservoirs based on geological models does better.With reservoir thickness and property parameters affecting seismic amplitudes,the method works better with amplitudes clearly revealing the physical properties of reef-shoal reservoirs and frequency attributes mapping the reservoir boundaries.