鄂尔多斯盆地南缘麟游-淳化地区平凉组礁滩体沉积特征及分布预测

Sedimentary characteristics and distribution prediction of Pingliang Formation reef⁃beach bodies in Linyou⁃Chunhua area of southern margin of Ordos Basin

鄂尔多斯盆地南缘平凉期发育规模生物礁滩型储层,目前对该区的研究主要集中在礁滩体的类型、成因、区域演化等方面,而对礁滩体的地球物理预测尚未开展系统研究。为了提高礁滩体的预测精度,建立礁滩体储层地震预测方法,通过野外露头实地踏勘,结合岩心及分析测试等资料,对镶边台地高能环境下的生物礁滩发育特征进行研究。通过已知井的井震响应特征,建立礁滩体正演模型,同时开展流体活动性、地震纹理属性分析,形成研究区礁滩体储层的地震预测方法。结果表明:鄂尔多斯盆地南缘平凉组主要发育碳酸盐岩台地边缘-浅水陆棚沉积体系;礁滩体主要分布于台地边缘亚相,多期叠置;高亮体和纹理属性对礁滩体的预测效果最好,2种方法的联合应用大大提高了礁滩体预测精度。研究成果为台缘带礁滩体平面分布规律预测和鄂尔多斯盆地南缘平凉组礁滩体的勘探开发奠定基础。

Large-scale reef-beach reservoirs were developed in Pingliang period in southern margin of Ordos Basin.Previous studies on this area mainly focused on the types,genesis and regional evolution of reef-beach bodies,but geophysical prediction of reef-beach bodies has not been systematically studied.In order to improve prediction accu-racy of reef-beach bodies and establish seismic prediction method,the development characteristics of reef-beach bodies in high-energy environment of rimmed platform is studied through outcrops field reconnaissance combining with core analysis and test data.Reef-beach forward model is established through seismic response characteristics of known wells,and fluid activity and seismic texture attribute are analyzed to form seismic prediction method for reef-beach reservoir in studied area.The results show that mainly carbonate platform margin-shallow water shelf sedi-mentary system developed during Pingliang period in southern margin of Ordos Basin.Reef-beach bodies are main-ly distributed in platform margin subfacieswith multi-period superimposition.Highlight bodies and texture attributes have the best prediction effect for reef-beach bodies,and combined application of these 2 methods significantly im-proves prediction accuracy of reef-beach bodies.The research provides basis for reef-beach body prediction in plat-form margin and exploration and development of reef-beach bodies of Pingliang Formation in southern margin of Or-dos Basin.