岩性反演在煤层顶板砂体识别中的应用  

Application of seismic lithology inversion in identifying sandstone of coalbed roof

作　　者：左卫华[1] 单蕊 朱伟[3] ZUO Weihua;SHAN Rui;ZHU Wei(Geophysical Prospecting and Research Institute,CNACG,Zhuozhou 072750,China;Xi'an Research Institute Co.Ltd.,China Coal Technology&Engineering Group Corp.,Xi'an 710077,China;College of Geophysics and Petroleum Resources,Yangtze University,Wuhan 430100,China)

机构地区：[1]中国煤炭地质总局地球物理勘探研究院,河北涿州072750 [2]中煤科工集团西安研究院有限公司,陕西西安710077 [3]长江大学地球物理与石油资源学院,湖北武汉430100

出　　处：《煤田地质与勘探》2018年第2期184-189,共6页Coal Geology & Exploration

摘　　要：EXB矿区主要目的层为一套泛滥平原河流相含煤碎屑岩沉积地层,煤层顶板岩性空间变化快,预测难度大。针对该问题,本文利用测井岩石物理分析建立煤、中砂岩、细砂岩和泥质砂岩的波阻抗频率直方图:煤的波阻抗值较小,主要范围3 000~6 300 m/s·(g/cm^3);中砂岩的波阻抗值域范围5 500~10 000 m/s·(g/cm^3);由于细砂岩和泥质砂岩性质接近,在波阻抗上无法区分,将两者合并处理,值域范围6 000~12 000 m/s·(g/cm^3)。然后利用叠后地震反演计算波阻抗体,利用岩相与流体概率分析技术预测煤层顶板岩性的空间展布。结果表明,地震预测的岩性及其厚度的宏观变化趋势与钻井揭示结果基本一致,岩性平面厚度分布规律与沉积环境相符。The main target strata of EXB mining area are a set of flood plain coal-bearing clastic sedimentary strata.The roof lithology of the coal seam changes rapidly and the lithology prediction is difficult.This paper used logging petrophysics analysis to establish the histogram of wave impedance of coal,medium sandstone,fine sandstone and shale sandstone.The impedance of coal was small with an upper limit of 7 500 m/s.(g/cm3).The impedance range of medium sandstone was between 5 500 and 10 000 m/s.(g/cm3).Elastic properties of fine sandstone and shale sandstone were close and indistinguishable in impedance.So the two rocks were merged and their impedance range was 6 000?12 000 m/s.(g/cm 3).The seismic impedance volume was calculated by poststack inversion,and the facies and fluids probabilities analysis were applied to predict the spatial distribution of the roof lithology.The result shows that macroscopic change of lithology and its thickness predicted by seismic inversion was consistent with drilling results and lithologically the law of planar distribution of thickness agreed with sedimentary environment.

关 键 词：岩性反演 顶板砂岩 岩相流体分析 

分 类 号：P631[天文地球—地质矿产勘探]