井地联合近地表品质因子场构建方法

    Near-surface quality factor field construction with micro-logging and seismic data

    • 摘要: 近地表结构通常较为松散,且其厚度与速度在纵、横向均表现出剧烈变化,不仅会显著吸收地震波能量,还可引起严重的相位畸变,从而显著降低地震记录的信噪比与分辨率。品质因子(Q值)通常用来描述地层的吸收特性。面对复杂的近地表结构,需同时考虑其纵、横向剧烈变化的特征,才能构建出精确的品质因子场。本文首先通过分析常用Q值反演方法的适应性,总结了基于微测井资料的品质因子反演方法的优选策略。为进一步提升近地表品质因子场建模精度,提出了一种通过融合微测井资料的高精度信息和反射波资料的高采样率信息,完成精确品质因子场模型构建的方法。实际数据测试结果表明,该方法能够准确刻画地层Q值的横向变化细节,补偿后地震波有效频带得以拓宽,地震资料分辨率显著提高,从而验证了本文方法的有效性。

       

      Abstract: Near-surface layers are typically characterized by loose structures and significant vertical and lateral variations in both thickness and velocity. These characteristics result in marked absorption of seismic wave energy and severe phase distortion, substantially reducing the signal-to-noise ratio (SNR) and resolution of acquired seismic records. The absorption properties of these layers can be described by the quality factor (Q-value). Given the complex structures of near-surface layers, constructing a precise quality factor field requires simultaneous consideration of their pronounced vertical and lateral variations. This study first summarized an optimization strategy for quality factor inversion based on data from uphole surveys by analyzing the applicability of common Q-value inversion methods. To further enhance the accuracy of near-surface quality factor field modeling, this study proposed a method for constructing precise quality factor field models. This method integrates high-resolution information from uphole survey data with high sampling-rate information from reflection wave data. Tests on real data demonstrate that the proposed method effectively captures detailed variations in lateral Q-values of the layers. The compensated seismic waves exhibited broadened effective frequency bands and significantly improved seismic resolution, thereby validating the effectiveness of the presented approach.

       

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