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    黏弹性介质Q处理技术在黄土塬区地震资料中的应用及成效

    Application and effectiveness of viscoelastic medium Q-processing in seismic data from loess tableland area

    • 摘要: 鄂尔多斯盆地油气资源丰富,受巨厚疏松黄土层对地震波强烈吸收影响,原始资料高频衰减严重、主频低、子波一致性差,严重制约了深层薄储层的精细预测。针对该问题,提出了融合近地表与中深层全层系补偿的黏弹性介质Q处理技术系列。首先在近地表补偿方面,采用峰值频率频移法对双井微测井数据求得Q-V经验关系,并利用层析速度场构建高精度三维Q场模型;进而应用炮域与检波点域分步补偿方法,实现了对近地表空变吸收效应的精准消除,有效提升了原始数据的分辨率和子波一致性。在此基础上,通过VSP数据约束与Q层析反演建立中深层Q场模型,并采用Q偏移技术,实现了沿地震波实际传播路径的振幅与相位补偿。实际资料处理结果表明,应用该技术系列后,频带拓宽了15Hz,深部弱信号能量得到有效恢复,薄煤层反射特征更加清晰,井震吻合度平均提升0.05,有效解决了黄土塬区地震资料吸收衰减补偿难题,为鄂尔多斯盆地致密气、煤层气等薄储层的精确勘探开发提供了可靠的技术支撑。

       

      Abstract: The Ordos Basin is rich in oil and gas resources. However, due to strong absorption of seismic waves by the thick unconsolidated loess formation, seismic data suffer from severe high-frequency attenuation, low dominant frequency, and poor wavelet consistency, which severely hinder the detailed prediction of deep thin reservoirs. To address this issue, this study proposes a viscoelastic medium Q-processing workflow that integrates full-stratum compensation from the near-surface to mid-deep zones. For near-surface compensation, the peak frequency shift method is applied to double-hole uphole survey data to obtain the Q-V relationship, and a high-precision 3D Q-field model is constructed using tomographic velocity fields. Furthermore, a stepwise compensation method in the shot and receiver domains is employed to accurately compensate for spatially variable near-surface absorption, effectively enhancing the resolution and wavelet consistency of the raw data. On this basis, a mid-deep Q-field model is built through VSP data constraints and Q tomographic inversion, and Q migration is then applied to achieve amplitude and phase compensation along the actual propagation paths of seismic waves. Field data application demonstrates that the frequency band is broadened by 15 Hz, deep weak signals are effectively restored, thin coal-seam reflections become clearer, and well-seismic consistency is improved by an average of 0.05. This effectively resolves the challenge of absorption and attenuation compensation in seismic data from the loess tableland area, providing reliable technical support for the exploration and development of thin tight gas and coalbed methane reservoirs in the Ordos Basin.

       

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