摘要
在前人研究基础上,结合鄂西建南地区最新钻井资料和地震解释成果,详细解剖该区长兴组沉积相特征及礁滩体沉积演化模式,提出了长兴组沉积早期发育碳酸盐缓坡、中—晚期发育碳酸盐台地的沉积模式,其中台地模式包括镶边台地和孤立台地,礁滩沉积主要发育于台地边缘相带。建南地区长兴组礁滩分布特征研究表明,南部以滩相沉积为主、北部以礁相沉积为主,其中礁、滩沉积体均发育于各层序的高位体系域,尤以第1个三级层序高位体系域最为发育。该区礁滩沉积是在相对海平面不断下降的背景下发育的,形成了一套规模较大的加积—进积型台地边缘生物礁、滩沉积序列。主要礁滩发育期可分为3个演化阶段,第1阶段以小规模低能滩相沉积为主,也是生物礁奠基阶段;第2阶段为大型障积型生物礁和生屑滩发育期;第3阶段为生物礁逐渐消亡阶段,该期生物礁以黏结—障积型生物礁为主。礁滩发育晚期的暴露浅滩白云石化作用强烈,形成良好的储集岩。
Based on previous researches,combined with recent drilling data and seismic interpretation of Jiannan area in western Hubei province,characteristics of sedimentary facies and evolution model of reefbank of Changxing Formation were studied in detail.At the early and middle-late stage of Changxing Formation,carbonate ramp and platform are developed respectively,of which the carbonate platform model includes rimmed platform and isolated platform,and reef-bank deposits are mainly developed in the platform margin.The distribution characteristics of reef and bank of Changxing Fomation show that reef facies is mainly located at the north part of the study area,and bank facies usually developed in the south.In the HST of each sequence,especially the first third-order sequence,reef-bank deposits are widely developed.As the relative sea level falls gradually,reef-bank deposits form a set of large-scale aggradational or progradational sedimentary succession.The development of reef and bank can be divided into three phases.During the first stage,low-energy bank deposits which are,developed on a small scale,are the basis of subsequent reefs.Large-scale baffle reef and bioclastic bank are formed at the second stage,and decayed at the third stage when bind-baffle reefs are developed.During the late stage for reef and bank development,favorable reservoir of Changxing Formation in study area is formed by extensive dolomitization of exposured shoals.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2014年第7期980-990,共11页
Natural Gas Geoscience
基金
湖北省自然科学基金项目(编号:2011CDB005)
高校博士学科点专项基金项目(编号:20124220110004)联合资助
关键词
建南地区
长兴组
沉积相
生物礁沉积
演化模式
Jiannan area
Changxing Formation
Sedimentary facies
Reef deposits
Evolution model
