• ISSN 2097-1893
  • CN 10-1855/P
聂南方,郭智奇,刘财. 2024. 改进的地震AVAZ裂缝弱度反演方法及其在致密砂岩储层中的应用. 地球与行星物理论评(中英文),55(3):358-368. DOI: 10.19975/j.dqyxx.2023-025
引用本文: 聂南方,郭智奇,刘财. 2024. 改进的地震AVAZ裂缝弱度反演方法及其在致密砂岩储层中的应用. 地球与行星物理论评(中英文),55(3):358-368. DOI: 10.19975/j.dqyxx.2023-025
Nie N F, Guo Z Q, Liu C. 2024. Application of the improved seismic AVAZ inversion method for fracture characterization of a tight sandstone gas reservoir in the Ordos Basin. Reviews of Geophysics and Planetary Physics, 55(3): 358-368 (in Chinese). DOI: 10.19975/j.dqyxx.2023-025
Citation: Nie N F, Guo Z Q, Liu C. 2024. Application of the improved seismic AVAZ inversion method for fracture characterization of a tight sandstone gas reservoir in the Ordos Basin. Reviews of Geophysics and Planetary Physics, 55(3): 358-368 (in Chinese). DOI: 10.19975/j.dqyxx.2023-025

改进的地震AVAZ裂缝弱度反演方法及其在致密砂岩储层中的应用

Application of the improved seismic AVAZ inversion method for fracture characterization of a tight sandstone gas reservoir in the Ordos Basin

  • 摘要: 致密砂岩气储层具有低孔、低渗的特征,裂缝的存在可以提高储层的渗透率,同时裂缝是油气重要的储存空间和运移通道,裂缝发育也有利于水力压裂过程中裂缝网络的形成,裂缝预测可为致密砂岩气储层的开发和部署提供重要依据. 地震振幅随方位角的变化可以提供储层中垂直裂缝的信息,本文针对HTI介质提出了一种改进的方位振幅差异反演方法,并结合岩石物理理论预测表征裂缝性质的裂缝弱度参数. 常规的反演方法一般同时反演弹性参数和裂缝参数,改进的方位振幅差异方法引入一个参考方位,构建消除各向同性背景的方位振幅差异道集,仅反演与各向异性项相关的裂缝弱度参数,充分利用方位各向异性响应,提高裂缝识别的敏感性与裂缝参数反演的准确性. 实际数据应用表明,方位振幅差异反演方法对裂缝参数预测的敏感性较常规方法有所提高,预测的裂缝弱度与测井渗透率曲线相吻合,并且与致密砂岩气储层产气性具有明显的相关性. 因此,利用方位振幅差异方法预测裂缝分布及其发育程度可为致密砂岩储层含气有利区的识别与开发提供可靠的指标.

     

    Abstract: A tight sandstone gas reservoir is characterized by low porosity and permeability. The existence of fractures can improve the permeability of the reservoir, and fractures are a vital storage space and migration channel of oil and gas. The development of fractures is also conducive to forming a fracture network during hydraulic fracturing. The prediction of fractures can provide an essential basis for developing tight sandstone gas reservoirs. The variation of seismic amplitude with azimuth can provide information on vertical fractures in the reservoir. This study proposed an improved inversion method of azimuth amplitude difference for the HTI (transversely isotropy with a horizontal axis) medium and combined with the rock physical theory, predicted fracture weakness parameter, characterizing the fracture properties. Conventional inversion methods invert elastic and fracture parameters simultaneously. The improved azimuth amplitude difference method introduces a reference azimuth, builds the track set of azimuth amplitude difference to eliminate the isotropic background, and inverts only the fracture weakness parameters related to the anisotropic terms. Using the only azimuth anisotropic response, the sensitivity of fracture identification and the accuracy of fracture parameter inversion are improved. The application of the field data shows that the sensitivity of the proposed inversion method to the prediction of fracture parameters is improved compared with the conventional inversion method, and the predicted fracture weakness is consistent with the permeability well logs and has a significant correlation with the gas production of tight sandstone gas reservoirs. Therefore, the prediction of fracture distribution and development degree based on the proposed method can provide a reliable indicator for the identification and development of gas-bearing favorable areas in tight sandstone reservoirs.

     

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