鄂西-城口地区“海槽”西侧长兴组-飞仙关组台缘礁滩特征与展布

通过鄂西-城口地区长兴组-飞仙关组露头、钻井、测井和地震等资料综合分析，对长兴组-飞仙关组台缘带及台缘礁滩特征取得了新认识：①长兴组-飞仙关组为镶边碳酸盐岩台地沉积，由东向西依次发育盆地相、斜坡相、台缘礁滩相、开阔台地相、局限台地相和蒸发台地相；②发育一条长兴期—飞仙关期的台缘带，长兴期以台缘礁组合为主，飞仙关期以台缘鲕滩为主，礁滩分布连续、厚度较大且延伸范围较广；③长兴期台缘礁由礁基、礁核和礁盖组成，礁核主要为粘结礁和障积-骨架礁，礁基和礁盖主要为生屑砂屑滩，分布于万源蜂桶、宣汉盘龙洞、开县满月、奉探1井和见天坝一带，迁移特征不明显；④飞仙关期台缘滩以鲕粒白云岩和鲕粒灰岩为主，分布稳定、范围大，向盆地方向，台缘滩由飞二段逐渐迁移至飞四段，飞二段台缘滩主要分布于万源八台、开县满月、万州双河、寨沟湾和石宝寨一带，飞三段台缘滩向东迁移至宁厂一线，飞四段台缘滩迁移至孔家沟一线，飞二段台缘滩与长兴期台缘礁叠合，白云岩化程度较高。

Characteristics and distribution of platform-margin reef-shoal reservoirs in Changxing-Feixianguan Formations to the west of ocean trough,E'xi-Chengkou area

An integrated analysis of outcrop, drilling, log and seismic data of the Changxing-Feixianguan Formations in E'xi-Chengkou area has led to new understandings of the characteristics of the platform-margin reef-shoal reservoirs therein.(1) The Changxing-Feixianguan Formations are a rimmed carbonate platform, composed of basin, slope, platform-margin reef-shoal, open platform, restricted platform and evaporated platform facies from east to west.(2) A platform-margin belt was developed during the sedimentation of Changxing-Feixianguan Formations with the Changxing Formation dominated by platform-margin reef facies and Feixianguan Formation by platform-margin oolitic shoal facies.This massive reef-shoal complex expands broadly and continuously in the area.(3) The platform-margin reef-shoal in the Changxing Formation consists of reef base, reef core and reef cap.The reef core is mainly cemented reef and baffle-frame reef, and the reef base and cap are mainly the biodetritus shoal facies distributed in Fengtong Township in Wanyuan City, Panlongdong Village in Xuanhan County, Manyue Township in Kaixian, Well Fengtan 1 and Jiantianba Township with no obvious signs of migration.(4) The platform-margin reef-shoal facies in the Feixianguan Formation is dominated by widespread oolitic dolomite and oolitic limestone and gradually migrating basinward from the second member to the fourth member of Feixianguan Formation.The facies in the second member is mainly distributed in Batai Town in Wanyuan City, Manyue Township in Kaixian, Shuanghekou of Wanzhou District in Chongqing, Zhaigouwan and Shibaozhai areas.The facies in the third member migrated eastward to Ningchang area, and that in the fourth member to Kongjiagou area.The shoal facies of the second member of Feixianguan Formation is highly dolomitized and superimposed onto the reef-shoal facies of Changxing Formation.