利用AVO属性研究构造煤的分布规律

Study on the distribution of deformed coal with AVO attributes

现行的煤田地震勘探技术主要解决煤层构造问题,不能对与瓦斯突出相关的构造煤分布、煤层和围岩的透气性做出评价,即无法评价煤岩层的岩性。近年来,国内外地球物理学家提出了利用AVO技术研究煤岩层岩性,查明构造煤发育区和瓦斯富集带。笔者首先对构造煤模型进行正演模拟,获得三维数据体;然后利用不同Zoeppritz近似方程对三维数据体进行AVO反演,得到多种AVO属性,通过对AVO属性的分析研究,提出利用Aki和Richards近似公式AVO反演得到的B值数据体、Shuey近似公式AVO反演得到的G值和Δσ值数据体作为AVO解释的基础;最后利用煤田实际三维地震资料进行AVO反演,尝试利用AVO属性圈定构造煤发育区和瓦斯富集带。

Currently the seismic exploration technique is mainly used to reveal the structure of coal beds, and cannot be used to evaluate the distribution of deformed coal, the permeability of coal beds and their roof/bottom, which are relat- ed to gas outburst. In other words,it cannot evaluate the lithology of coal beds and rock strata. In recent years, some geophysicists suggest to investigate the lithology of coal beds and rock strata, and define the deformed coal distribution and gas concentrated area with AVO technique. In this paper, a 3D seismic cube of deformed coal model was initially obtained using seismic simulation. Subsequently, AVO inversions for the 3D seismic cube were calculated using differ- ent Zoeppritz approximate equations,and many AVO attributes were obtained. Through the analysis of AVO attributes, it was proposed that the B-value cube inversed with Aki ＆ Richards approximate equation, and the G-value cube and △δ cube inversed with Shuey approximate equation are used as the basis of AVO interpretation. Finally, AVO inver- sions for real 3 D coal seismic data were performed to define the distribution of deformed coal and gas concentrated are- as using AVO attributes.