岩性油藏弱反射地震储层预测方法研究

准噶尔盆地车排子地区发育多套地层超覆在石炭系上,易形成丰富的岩性油藏。由于上覆地层与石炭系的岩性物性差异巨大,储层的反射淹没在强振幅中,很难利用常规的储层预测方法有效刻画储层的纵横向分布。针对此问题,首先阐述了该地区岩性油藏弱反射形成机理、地震资料分辨率;然后开展了拓频、反演、分频、地震属性分析等多种储层预测方法研究;在此基础上,将包含岩性油藏的弱反射信号看成整体,而不是分离出来,从而优选出能够反映信号微弱变化的标准偏差属性进行岩性油藏储层预测。研究结果表明:利用标准偏差属性预测的储层结果与现有钻井资料吻合很好,为该地区岩性油藏勘探开发提供了有效的技术手段和新的研究思路,也为认识此类岩性油藏特征具有重要的指导意义。

Studying Methods of Weak Seismic Reflection of Lithologic Reservoir to Predict Reservoirs

Multi-strata onlap in the Carboniferous developed in the Chepaizi area of the Junggar Basin are easy to form rich lithologic reservoir resources. Due to the huge differences in the lithologic and physical properties of the overlying strata and Carboniferous, reflections of the reservoir submerged in the strong amplitudes cause it difficult to use conventional reservoir prediction methods for effective characterization of the vertical and horizontal distribution of the reservoir. To solve this problem, the mechanism of the weak reflection of the lithologic reservoir and the resolution of seismic data in the region are first elaborated. Then frequency extension, inversion, spectral decomposition and seismic attribute analysis and so on are carried out. Finally, we adjust the research approach to include the weak reflection signals in the lithologic reservoir as a whole, rather than isolated, to select the standard deviation attributes which can reflect the weak changes of the seismic traces to lithologic reservoir prediction. The results show that the standard deviation attributes can give a reservoir prediction result well agreeing with the existing drilling data. The proposed method provides effective techniques and new research ideas for lithologic reservoir exploration and development in the region. It also has important guiding significance for the understanding of the characteristics of these lithologic reservoirs.