ISSN 1004-4140
CN 11-3017/P

分频AVO技术在西湖凹陷中深层薄储层评价中的应用

Application of split-frequency AVO technology in the evaluation of middle-depth thin reservoirs in the Xihu Depression

  • 摘要: 受限于薄层地层结构、厚度及流体等因素综合影响,薄层波场特征比较复杂,导致其薄层AVO分析存在较大不确定性。针对薄层复杂薄层模拟问题,本文利用反射率法进行薄储层AVO正演模拟,发现薄层的AVO响应由于调谐效应,远偏移距存在明显“V”字型特征。通过对不同频带的薄层叠前道集对比分析,明确地震频带越宽,叠前道集AVO振幅曲线越稳定。借助高分辨率时频分析方法,对不同频带叠前道集进行分频扫描分析,优选地震频带中AVO信息稳定变化的优势信息进行重构,可进一步提高AVO分析的稳定性。通过实际叠前道集验证分析,利用叠前道集优势频带信息,可以有效提高烃类检测可靠程度,为西湖凹陷中深层烃类检测提供有力技术支撑。

     

    Abstract: Owing to the combination of factors such as the thin layer structure, thickness, and fluid, the wave field characteristics of the thin layer are relatively complex, which results in large uncertainties in the thin layer AVO analysis. To address the complex thin layer simulation problem, this study uses the reflectivity method to conduct AVO forward simulations of thin reservoirs, and finds that the AVO response of the thin layer has an obvious “V” feature at the far offset owing to the tuning effect. Comparing and analyzing the thin layer pre-stack gather in different frequency bands clearly shows that the seismic frequency band is wider and that the AVO amplitude curve of the pre-stack gather is more stable. Using high-resolution time-frequency analysis, the AVO stability can be further improved by performing the frequency scanning analysis on the pre-stacked gather of different frequency bands and selecting the advantageous information of the AVO information that changes stably in the seismic frequency bands to be reconstructed. Through the actual pre-stack gather verification analysis, the advantageous frequency band information of the pre-stack gather can effectively improve the reliability of hydrocarbon detection and provide powerful technical support for the detection of hydrocarbons in the middle and deep layers of the Xihu Depression.

     

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