基于多构造属性联合约束的速度建模方法以珠江口盆地恩平凹陷为例

    Velocity modeling under joint constraint of multiple structural attributes: a case study of Enping Sag in Pearl River Mouth Basin

    • 摘要: 复杂断块区域的高精度速度建模是解决成像剖面中断层阴影问题的有效方法。以南海珠江口盆地恩平凹陷A构造区域速度建模为例,发展了一种基于层位、断层以及倾角等多种构造属性联合约束的建模方法。该方法首先根据当前的地质认识,结合已有的钻井资料建立初始速度模型,然后将断层、层位及能体现断裂特征的倾角等构造属性联合约束在层析反演的过程中,最终可迭代得到精细的速度模型。该方法可更准确地保留住断层两侧速度的差异性,与实际地层更加吻合。基于所得速度模型的地震深度偏移成像处理显示,成像剖面中断层阴影区成像更加连续,断点清晰,成像质量明显优于老资料。

       

      Abstract: High precision velocity modeling in complex fault block area is an effective method to solve the problem of fault shadow in imaging profile. We developed a velocity modeling method based on the joint constraints of multiple structural attributes, including horizon, fault, and dip for the structural region A in the Enping Sag, Pearl River Mouth Basin, South China Sea. In the method, the initial velocity model is established based on existing drilling data and available geological knowledge, and then the joint constraints of structural attributes reflecting fault characteristics are added into the tomographic inversion. Finally, the refined velocity model can be obtained iteratively. It can retain more accurately the velocity difference between the two sides of the fault, and more consistent with the actual stratigraphic units. The seismic depth migration imaging processing based on the velocity model shows that the imaging of the fault shadow area in the imaging section is more continuous, the breakpoint is clear, and the imaging quality is obviously better than the old data.

       

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