含煤地层多波AVO地震响应  

Multi-wave AVO seismic responses of coal bearing strata

作　　者：安莹 芦俊[1] 杨春[2,3] AN Ying;LU Jun;YANG Chun(Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism, Ministry of Education, China University of Geoscience （ Beijing）, Beijing 100083 ,China;School of Geophysics and Information Technology,China University of Geoscience （ Beijing ） ,Beijing 100083 ,China;Academy of Sciences, China University of Geoscience （Beijing） ,Beijing 100083, China)

机构地区：[1]中国地质大学(北京)海相储层演化与油气富集机理教育部重点实验室,北京100083 [2]中国地质大学(北京)地球物理与信息技术学院,北京100083 [3]中国地质大学(北京)科学研究院,北京100083

出　　处：《煤炭学报》2018年第3期793-800,共8页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(41574126;41425017);国家"十三五"重大专项资助项目(2016ZX05002-005-008)

摘　　要：传统的煤层AVA分析基于各向同性理论,而煤层通常表现为厚度小、互层分布、低速和低密度的特点,使得含煤地层呈现为各向异性,因此各向同性理论难以描述含煤地层的地震响应特征。为了能更准确的获得含煤地层的多波地震响应,基于各向异性理论和长波长理论,将含煤地层等效为具有垂直对称轴的横向各向同性介质,根据煤层总厚度与含煤地层总厚度的比值和煤层厚度与波长的比例建立模型,采用Ruger的反射系数方程,从AVA曲线和AVO道集等方面分析不同模型随着入射角改变的地震响应。结果表明:互层结构、煤层厚度与波长的比例都会影响含煤地层的多波地震响应;忽视含煤地层的各向异性会对实际地震响应研究造成较大的误差;综合利用PP波和PS波能更好的描述含煤地层的各向异性。The traditional AVA analysis of coal seam is based on the seismic isotropic theory,while the coal seam usually shows the characteristics of small thickness,cross layer distribution,low velocity and low density,which makes the coal bearing strata appears anisotropic.Therefore,the seismic responses of coal bearing strata are difficult to be described by the seismic isotropic theory.In order to obtain the multi-wave seismic responses more accurately,the coal bearing strata are equivalent to transversely isotropic media with vertical symmetry axis based on the seismic anisotropy and long-wavelength theory.The models are established according to the ratio of the total thickness of coal seam to the coal bearing strata and to the wavelength.By using the reflection coefficient equations of Ruger,the multi-wave seismic responses of different models with varying incident angle are analyzed in terms of AVA curves and AVO gathers.The results show that：both the interlayer structure and the ratio of the thickness of coal seam to the wavelength will affect the multi-wave seismic responses of coal bearing strata.Neglecting the anisotropy of coal bearing strata will cause a large error in the study of actual seismic responses,and using PP wave and PS wave simultaneously can better describe the anisotropy of coal bearing strata.

关 键 词：含煤地层 各向异性 多波 地震响应 

分 类 号：P631.4[天文地球—地质矿产勘探]