摘要
四川盆地高石梯地区震旦系灯影组四段台缘带油气资源储量巨大,藻丘的发育是优质储层形成的基础,因此讨论四川盆地高石梯地区的藻丘类型与沉积模式就显得尤为重要。通过岩心观察、薄片鉴定并结合测井资料,详细阐述了高石梯地区灯四段的藻丘类型与沉积模式。研究结果表明:1)该地区岩石类型可分为富藻类云岩和贫藻类云岩:富藻类云岩是藻丘的丘基和丘核的主要类型,藻格架较发育,具有叠层构造、藻纹层构造、藻绵层构造等;贫藻类云岩发育在丘间、台坪和潮坪—潟湖环境,以晶粒云岩为主,局部含石膏;2)基于岩性组合、沉积构造和地球化学参数,藻丘可分为大型藻丘、较稳定中型丘和低能小型藻丘:大型藻丘发育在低盐度水体较浅的台缘外侧高能带,Rb/K为1.3~2.0;中型藻丘发育在较高盐度和较浅水的台缘内侧至台地内部,Rb/K>2.0。通过建立藻丘及其周缘的沉积模式,进一步明确了研究区藻丘的类型及其分布规律。
Considerable hydrocarbon resources are present in the 4 th member of the Sinian Dengying Formation,at the platform margin in the Gaoshiti area of the Sichuan Basin. Therefore,it is particularly important to discuss the algal mound developments in that area,since they are the basis of the formation of high-quality hydrocarbon reservoirs.Analysis of cores,thin-section identification and logging data have elaborated the algal mound types and sedimentary models of the Deng 4 member in detail. The results show:(1)Algae-rich dolomite is the main type of algal mound foundation and nucleus,having algal frame,stromatolitic structures,algal laminated structures and algal sponge layer structures. Algae-poor dolomite was developed in shallow open marine zones,tidal flats and lagoons,and is predominantly crystalline dolomite containing some gypsum.(2)The lithological combination,sedimentary structure and geochemical parameters indicate that algal mounds may be categorized as large algae mounds,medium-sized stable algae mounds,and small algae mounds which occur in low-energy environments. The large algae mounds were developed in the high-energy band lying outside the platform margin of a low-salinity water body,and have a Rb/K ratio of approximately 1.3-2.0. The medium-sized stable mounds are located from the medial margin of the platform to the interior of the platform,formed in higher-salinity and shallower water;their Rb/K ratio is > 2.0.(3)A sedimentary model of algal mounds and their periphery was established;the study also clarified the types and lateral extents of the mounds. These findings may guide exploration for favorable areas in the inner platform.
作者
郭恒玮
伏美燕
宋荣彩
刘文
赵亮
沈秋媛
GUO HengWei;FU MeiYan;SONG RongCai;LIU Wen;ZHAO Liang;SHEN QiuYuan(College of Energy,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;College of Geosciences,Chengdu University of Technology,Chengdu 610059,China;Shu’nan Gas-mine Field,Southwest Oil&Gas Field Branch Company,China National Petroleum Corporation,Chengdu 646000,China)
出处
《沉积学报》
CAS
CSCD
北大核心
2022年第1期217-228,共12页
Acta Sedimentologica Sinica
基金
国家科技重大专项(2016ZX05036-003-007)
国家自然科学基金(41402096)~~。
关键词
藻丘
沉积模式
灯影组四段
高石梯地区
algal mound
sedimentary model
4th member of the Dengying Formation
Gaoshiti area
