陕甘宁盆地鄂托克前旗地区奥陶系风化壳的地震正演模型  

The Study of Morphology of Ordovician Weathered Crust with Conceptual Seismic Model in Ertuokeqianqi, Ordos Basin

作　　者：卫延召[1] 冯江 宋海明[2] 王多云[2] 

机构地区：[1]北京石油勘探开发科学研究院,北京100083 [2]中国科学院兰州地质研究所,兰州730000

出　　处：《沉积学报》1999年第A12期734-741,共8页Acta Sedimentologica Sinica

摘　　要：针对鄂托克前旗地区下古生界奥陶系风化壳形态，以二维地震资料为主，辅之以钻井及测井资料，利用概念性地震模型正演法，通过地质模型一模拟响应一实际地震剖面三者的对比分析，初步建立起研究区不同古地貌单元同实际地震测线特征之间的对应关系，并藉此识别掌握了研究区奥陶系古风化壳的单测线特征，对在地震测线上风化壳标志层的标定及奥陶系风化古地貌的恢复都有具有重要意义。The discovery and study of Changqing Gas Field in Ordos Basin has shown the gas exploration prospect of Paleozoic, especially the weathered crust gas reservoir of Ordovician System. Ertuokeqianqi is one of the most favorable regions for gas exploration, and it has,been paid much attentions for many years.Mainly based on 2-D seismic data and coupled with drilling and well logging data, we studied and described the seismic characteristics of the morphology of the weathered crust of Ordovician, Ertuokeqanqi, Ordos Basin through geological and seismic models.Firstly, through the study of drills, well logs and sonic synthetic seismograms, we mastered the characteristic essentials of objective formations-the different sonic velocity between upper Paleozoic and lower Paleozoic and the two coal fornlations and their seismic characteristic. At the same time, we also understood the relations of Lithology and Logging parameters, which lays a foundation for developing seismic models.Furthermore, we divided the shapes of the Ordovician weathered crust into four conceptual models,namely, paleotableland, paleopit, paleovalley and paleoslope. Using these models, we elementarily established the corresponding relations between paleogeornorphology and seismic characteristic with the analysis and comparison of geological models, seismic reflectiorl and practical reflection. We have found that the distance between the lower coal formation and Ordoviciari weathered crust had important relations with the seismic characteristics.Finally, this research is very valuable to interpret and calibrate the weathered crust of Ordovician system on seismic log and to draw the horizontal maps of the relic Ordovician formation over the M55. The maps nlight reflect the morphology of the weathered crust, and which is helpful to find Ordovician weathered crust gas reservoir and direct the gas exploration in Ertuokeqianqi, ordos Basin.

关 键 词：奥陶系 风化壳 盆地 地震正演模型 天然气田 

分 类 号：P618.130.8[天文地球—矿床学] P512.13[天文地球—地质学]