【摘要】 湘西北地区发育寒武系下统牛蹄塘组、志留系下统龙马溪组两套富有机质黑色页岩。通过合成地震记录和已知地质特征推断反射层位的方法,对两套含烃黑色页岩层的地震地质特征、波组层位识别、波组特征进行了分析对比,总结出湘西北地区页岩层地震反射波所具有的典型特征:龙马溪组存在3~4个强相位,主频集中在30Hz左右;牛蹄塘组存在3个强反射界面,因深度加大,其主频集中在20Hz左右。由于龙马溪组和牛蹄塘组二组地层间距达2 500~3 000m,因此在湘西北地区将二组地层的反射波视作一个波系,其二维地震剖面存在3个波组4个反射层位或3个波组3个反射层位,三个波组分别为龙马溪组,中寒武底界及牛蹄塘组。另外因龙马溪组砂质泥岩段具有低速、低密度、低电阻率、高放射性等特征,其界面波阻抗差异较大,可作为本区的地震波标志层位。更多还原

【Abstract】 The lower Cambrian Niutitang Formation and lower Silurian Longmaxi Formation two sets of organic matter rich black shale have been hosted in northwestern Hunan region. Through synthetic seismic records and known geological features deduced reflecting layer horizon, analyzed and compared seismic-geologic characteristics, wave group horizon identification, wave group characteristics of the two sets hydrocarbon-bearing black shale strata, summed up shale strata seismic reflection typical features including: in Longmaxi Formation exists 3~4 strong legs, dominant frequency concentrated at 30 Hz about; in Niutitang Formation exists 3 strong reflectors, because of depth deepening, dominant frequency concentrated at 20 Hz about. Because of interval between the two sets can be up to 2500-3000 m, thus the reflection of the two sets in the area being seen as one wave system. On its 2D seismic section exists 3 wave groups, 4reflecting layer horizons or 3 wave groups, 3 reflecting layer horizons, the 3 wave groups are Longmaxi Formation, middle Cambrian bottom and Niutitang Formation. Besides, since the Longmaxi Formation sandy mudstone member is characterized by low velocity, low density, low resistivity and high radioactivity, its interface wave impedance variable, can be the seismic wave indicator horizon in the area.更多还原