四川盆地五峰组—龙马溪组页岩岩相类型与沉积环境  

Lithofacies types and sedimentary environment of shale in Wufeng-Longmaxi Formation,Sichuan Basin

作　　者：赵建华[1] 金之钧[2] 金振奎[1] 温馨[1] 耿一凯 颜彩娜[3] 聂海宽[2] 

机构地区：[1]中国石油大学地球科学学院,北京102249 [2]中国石油化工股份有限公司石油勘探开发研究院,北京100083 [3]中国地质大学能源学院,北京100083

出　　处：《石油学报》2016年第5期572-586,共15页Acta Petrolei Sinica

基　　金：中国博士后科学基金<富有机质页岩中自生石英成因机制及对页岩气勘探的意义>(No.2016M591350);国家自然科学基金项目<高热演化条件下页岩气聚集机理和评价方法研究>(No.41202103);中国石油化工股份有限公司科技攻关项目<川东地区龙马溪组页岩气富集规律与分布预测>(G5800-14-ZS-KJB158)资助

摘　　要：沉积物的搬运过程和环境条件控制着富有机质页岩的形成。根据矿物学、岩石组构、生物组成及沉积构造的不同,五峰组—龙马溪组页岩识别出7种岩相类型:硅质页岩、粉砂质页岩、黏土质页岩、灰质页岩、含介壳灰岩泥质/泥灰岩、粉砂岩—细砂岩和斑脱岩。五峰组—龙马溪组页岩并不是一直在低能的水动力条件下以悬浮的形式沉积,大量硅质生物化石、具粒序特征的生物碎屑、粉砂纹层、透镜状层理及沙纹交错层理等沉积构造表明,还存在生物沉积、风暴沉积和底流沉积作用。微量元素分析表明五峰组和龙马溪组下部硅质页岩形成于贫氧/缺氧环境,富含有机质;随后海平面逐渐下降,同时受到底流的影响,岩相类型向粉砂质页岩和黏土质页岩转变,贫氧/缺氧环境受到破坏,有机质的保存条件逐渐变差。T he form ation of organic-rich shale was controlled by sedim ent transport and deposition processes as well as sedim entaryenvironm ent conditions. Based on m ineralogy as well as different rock fabrics, biotic com ponents and sedim entary textu res, seventypes of shale lithofacies w ere identified in W ufeng-Longm axi Form ation; siliceous shale, silty shale, argillaceous shale, calcareousshale,shell-bearing lime m u dsto ne/m arl,siltstone-fine sandstone and bentonite. T he shale in W ufeng-Longm axi Form ation was notalw ays able to deposit in a suspending form under the low-energy hydrodynam ic conditions. A large num ber of siliceous biologicalfo ssils, biological detritus w ith grading characteristics, silt lam inations, lenticular bedding, ripple cross-bedding and other sedim entarytextures indicate that biogenic deposition, storm deposition and bottom current deposition also existed. T race elem ent analysissuggests that the siliceous shale in the low er part of W ufeng-Longm axi Form ation was form ed in the dysoxic/anoxic environm ent,which was rich in organic m atters. T hen, sea level gradually declined. M eanw hile, influenced by bottom cu rren t, lithofacies typesw ere changed and show n as silty shale and argillaceous shale, while dysoxic/anoxic environm ent was dam aged〉 resulting in the graduallyw orsening preservation conditions of organic m atter.

关 键 词：沉积环境 富有机质页岩 岩相类型 沉积过程 缺氧环境 

分 类 号：TE122.14[石油与天然气工程—油气勘探]