多波叠前联合反演技术在委内瑞拉Junin4区块的应用

与纵波叠前AVO反演相比,多波叠前联合反演既有实测的纵波与转换波地震数据又保留了各自叠前AVO信息,将纵波速度与横波速度以及纵波速度与密度之间的相互关系作为约束条件,能够提高反演结果的精度和可靠性,获得高精度的横波阻抗和密度参数。以委内瑞拉奥里诺科重油带Junin4区块浅层疏松砂岩储层为研究目标,阐述了多波叠前联合反演的基本原理,给出了多波叠前联合反演的关键步骤,进行了岩石物理分析,优选对储层敏感的密度参数,并利用多波叠前联合反演的密度参数完成了Junin4区块疏松砂岩储层及泥岩隔层预测,其中砂岩储层预测符合率达91%,泥岩隔层预测符合率达86%,较纵波地震储层预测精度有大幅度提高,展示了多波地震资料在浅层未固结疏松砂岩超重油油藏地质条件下的良好应用效果。

 Multi-wave pre-stack joint inversion adopts both measured P- and S-wave seismic data and retains separate AVO information.Using the relationship between P- and S-wave velocity and that between P-wave velocity and density as constraint conditions of the joint inversion can improve the reliability of inversion results and obtain accurate S-wave impedance and density.In this study,considering the shallow unconsolidated sandstone reservoir in the Junin4 block of the Orinoco heavy oil belt in Venezuela as the study target,the basic principle and key steps of multi-wave pre-stack joint inversion are introduced for reservoir prediction.Rock physical analysis is then carried out to optimize reservoir-sensitive density parameters.The unconsolidated sandstone reservoir and mudstone interlayer are predicated by the density parameter delineated from multi-wave pre-stack joint inversion in Junin4 block.The coincidence rate for sandstone reservoir prediction is 91% and that for mudstone interlayer prediction is 86%.The prediction accuracy is clearly better than that obtained with P-wave reservoir prediction.This indicates the good application potential of multi-wave seismic data in the extra-heavy oil reservoir with shallow unconsolidated loose sandstone.

基金项目：国家科技重大专项课题“超重油油藏冷采稳产与改善开发效果技术”(编号:2016ZX05031-001)资助。