有机质含量对页岩声波传播特性的影响
发布时间：2018-11-08 18:04
【摘要】：有机质是含气页岩的重要组分之一,有机质含量及类型在相当大程度上控制着页岩的孔隙度及含气性。前人工作多关注页岩矿物组分及其赋存方式所导致的声速及力学性质各向异性方面,而对有机质含量与页岩声波传播响应特性的关系则很少研究。以鄂尔多斯盆地三叠系延长组长7段富有机质页岩为研究对象,利用自行研制的SCMS-J型声电测试仪,采集15MPa围压下页岩纵/横波传播信息,分析有机质含量对纵/横波传播速度及页岩力学性能的影响,并运用快速傅里叶变换对采集的岩样声波波形数据进行频谱分析。研究表明:(1)纵/横波传播速度随着有机质含量增加而减小,纵/横波波速比随着有机质含量增加而增大;(2)页岩动态剪切模量G、动态体积模量K和动态弹性模量E随着有机质含量增加而降低,而泊松比v随着有机质含量增加而增大;(3)有机质含量越高,高频部分吸收越明显,主频向低频移动,形心频率f_c大小与有机质含量呈负相关。研究成果对基于声波测井信息评价页岩有机质含量及含气性具有一定的借鉴意义。
[Abstract]:Organic matter is one of the important components of gas-bearing shale. The content and type of organic matter control the porosity and gas-bearing property of shale to a great extent. Previous studies have focused on the anisotropy of acoustic velocity and mechanical properties caused by shale mineral components and their occurrence patterns, but little on the relationship between the content of organic matter and the response characteristics of shale acoustic wave propagation. Taking the organic shale of Chang 7 member of the Triassic Yanchang formation in Ordos Basin as the research object, using the SCMS-J type acoustoelectric tester developed by ourselves, the longitudinal / shear wave propagation information of shale under 15MPa confining pressure is collected. The influence of organic matter content on the propagation velocity of longitudinal / shear wave and the mechanical properties of shale is analyzed. The spectrum analysis of acoustic wave data of rock samples is carried out by using fast Fourier transform (FFT). The results show that: (1) the propagation velocity of P / S wave decreases with the increase of organic matter content, and the velocity ratio of P / S wave increases with the increase of organic matter content; (2) dynamic shear modulus G, dynamic bulk modulus K and dynamic elastic modulus E decrease with the increase of organic matter content, while Poisson's ratio v increases with the increase of organic matter content; (3) the higher the organic matter content, the more obvious the absorption of the high frequency part is, the main frequency moves to the low frequency, and the centroid frequency FSC is negatively correlated with the organic matter content. The results can be used for reference in the evaluation of shale organic matter content and gas content based on acoustic logging information.
【作者单位】： 西南石油大学油气藏地质及开发工程国家重点实验室;
【基金】：国家自然科学基金面上项目“富有机质页岩氧化致裂增渗加速气体传输机理研究”(编号:51674209) 非常规油气层保护四川省青年科技创新研究团队项目(编号:2016TD0016)联合资助
【分类号】：P618.13;P631.81
[Abstract]:Organic matter is one of the important components of gas-bearing shale. The content and type of organic matter control the porosity and gas-bearing property of shale to a great extent. Previous studies have focused on the anisotropy of acoustic velocity and mechanical properties caused by shale mineral components and their occurrence patterns, but little on the relationship between the content of organic matter and the response characteristics of shale acoustic wave propagation. Taking the organic shale of Chang 7 member of the Triassic Yanchang formation in Ordos Basin as the research object, using the SCMS-J type acoustoelectric tester developed by ourselves, the longitudinal / shear wave propagation information of shale under 15MPa confining pressure is collected. The influence of organic matter content on the propagation velocity of longitudinal / shear wave and the mechanical properties of shale is analyzed. The spectrum analysis of acoustic wave data of rock samples is carried out by using fast Fourier transform (FFT). The results show that: (1) the propagation velocity of P / S wave decreases with the increase of organic matter content, and the velocity ratio of P / S wave increases with the increase of organic matter content; (2) dynamic shear modulus G, dynamic bulk modulus K and dynamic elastic modulus E decrease with the increase of organic matter content, while Poisson's ratio v increases with the increase of organic matter content; (3) the higher the organic matter content, the more obvious the absorption of the high frequency part is, the main frequency moves to the low frequency, and the centroid frequency FSC is negatively correlated with the organic matter content. The results can be used for reference in the evaluation of shale organic matter content and gas content based on acoustic logging information.
【作者单位】： 西南石油大学油气藏地质及开发工程国家重点实验室;
【基金】：国家自然科学基金面上项目“富有机质页岩氧化致裂增渗加速气体传输机理研究”(编号:51674209) 非常规油气层保护四川省青年科技创新研究团队项目(编号:2016TD0016)联合资助
【分类号】：P618.13;P631.81
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