川东北地区长兴期—飞仙关期沉积体系分析

Depositional system of Changxing-Feixianguan period in Northeastern Sichuan Basin

(1.成都理工大学沉积地质研究院，四川成都610059;2.成都理工大学“油气藏地质及开发工程”国家重点实验室,四川成都610059;3.内蒙古地质矿产勘查院,内蒙古呼和浩特010011)

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China

对川东北地区长兴期—飞仙关期沉积体系及沉积相展布规律的研究可以为该地区进一步的油气勘探部署提供重要的地质依据。以沉积学、地震地层学理论为指导,综合分析野外剖面、钻井和地球物理资料,将研究区长兴期—飞仙关期沉积划分为碳酸盐岩台地和台盆两种沉积体系,其中碳酸盐岩台地沉积体系又可划分为蒸发台地、局限台地、开阔台地、台地边缘生物礁、浅滩和台地边缘斜坡5种沉积相带。长兴期—飞仙关二期为台地和台盆相间的沉积相展布格局,具有飞仙关一末期开始快速填平补齐,飞仙关三期为碳酸盐岩台地,飞仙关四期为蒸发台地的演化特征。长兴期台地边缘礁、滩组合和飞仙关期台内浅滩是该地区储层发育的有利沉积相带。

The study on the depositional system and the distribution pattern of sedimentary facies of Changxing Formation and Feixianguan Formation provides important geological basis for further hydrocarbon exploration deployment in the area.By analyzing field outcrop profile,drilling information and geophysical data,according to the theory of sedimentology and seismic stratigraphy,the depositional systems of Changxing-Feixianguan period were classified into carbonate platform and carbonate platform-basin.The carbonate platform can be divided into five depositional belts.Including evaporate platform,restricted platform,open platform,platform margin reef,shoal and platform margin slope.The distribution pattern of sedimentary facies of Changxing period to the second Feixianguan period is platform altered with platform-basin.The rapid filling process started from the end of the late first Feixianguan period,then it homogenized into carbonate platform during the third Feixianguan period,and it turn into evaporate platform in the forth Feixianguan period.The combination of platform margin reef and shoal in Changxing period and shoal in platform in Feixianguan period is the favorable depositional facies.