基于波形聚类的沉积微相定量解释技术研究——以中东地区X油田为例

Quantitative interpretation of sedimentary microfacies based on waveform clustering:a case study of X oilfield,Middle East

中东地区X油田礁滩储层薄、纵横向沉积相变化快、非均质性强,因而不同岩相的油气产量差异较大,同时使得基于地震波形的沉积微相定量描述受到处理、解释以及聚类方法与参数等不同因素的影响。为提高储层沉积微相的预测精度,在一定程度上降低或消除上述因素的影响,提出了高精度层序地层格架约束下的基于波形相对变化的波形-微相定量表征综合解释技术,主要包括:(1)相对保幅的叠后高分辨率处理;(2)全三维高精度地层扫描解释与井震层序标定;(3)波形特征参数分析与分类;(4)波形-微相聚类与定量表征。基于波形聚类的沉积微相定量解释技术应用研究表明,地震资料的保幅处理是研究微相分类的前提,高频地震层序约束下的井震标定与波形聚类是沉积微相定量表征的核心。该方法是解决非均质碳酸盐岩储层岩相预测的有效方法之一。

X Oilfield in the Middle East,is a carbonate reef-shoal reservoir with complex sedimentary facies,strong heterogeneity,which cause large difference of oil and gas production in different facies.Quantitative characterization of sedimentary microfacies based on seismic waveform is heavily influenced by different factors,such as the processing,interpretation and clustering methods and parameters.To reduce or eliminate the above influencing factors and enhance the predicted accuracy of microfacies,in this paper we present waveform-microfacies quantitative interpretation techniques based on the relative change of seismic waveform under the constraints of a high resolution sequence stratigraphic framework.The four key steps are as follows:relatively amplitude-preserved poststack high resolution processing,full 3D high precision formation scanning interpretation and well-seismic joint calibration,analysis and sorting of waveform parameters,and clustering and quantitative characterization of waveform-microfacies.Based on the aforementioned interpretation techniques,studies show that amplitude reserved processing is a precondition of microfacies classification.Well seismic calibrations and waveform clustering with the constraint of a high frequency seismic sequence are core principles of the quantitative characterization of sedimentary microfacies,and this is an effective method to predict the lithofacies of a heterogeneous carbonate reservoir.