西沙海域新生代生物礁序列的沉积构成:以西科1井为例  

Sedimentary Composition of Reef Succession Since Cenozoic in Xisha Areas: An Example from the Xike-1 Well

作　　者：赵新伟[1] 许红[2] 孙志鹏 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]国土资源部青岛海洋地质研究所,山东青岛266071 [3]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《现代地质》2016年第4期852-862,共11页Geoscience

基　　金：国家科技重大专项(2011ZX05025-002)

摘　　要：生物礁是由原地的固着生物所建造的块状碳酸盐岩沉积。西沙海域自中新世以来发育了厚层生物礁地层。通过对最新全取心钻井西科1井岩心的宏观观察和微观分析,结合古生物及岩心测试成果,发现西科1井中新世和第四纪为主要造礁期,形成了两套分别以珊瑚藻和珊瑚为主要造礁生物的生物礁序列,底栖有孔虫为主要的附礁生物,而上新统为一套滩相沉积。生物礁序列发育骨架岩、粘结岩和障积岩三种礁相岩石,以骨架岩含量最高,非礁相岩石包括泥灰岩、颗粒灰岩和生物碎屑灰岩三种。白云岩地层以晚中新世到上新世早期最为发育,多为准同生白云石化作用所致,并受热液活动的影响。对生物礁序列的沉积分析,可为后期南海油气勘探以及生物礁储层分布研究提供一些基础材料。Reefs are essentially in place calcareous deposits created by sessile organisms. Xisha areas developed thick strata of reef that are formed since the Miocene. Using microscopic and macroscopic observation for the Xike-1 well that is full-coring,combing with paleontology and core test results,we found that Miocene and Quaternary were the main reef-building stages in the Xike-1 well,then formed two sets of reef succession that is respectively masked by the coralline algae and the coral as the main reef-building organism,in which accessory reef organisms are benthic foraminifera. However,Pliocene developed a set of bank-facies deposits. The rock type of this reef succession principally include framestone,boundstone and bafflestone,in which framestones are dominated. Non-reef facies rocks included marlstone,grain limestone and bioclastic limestone. Dolomite formation developed extensively in the Late Miocene to Early Pliocene,which was more caused by the penecontemporaneous dolomitization and affected by hydrothermal activity. Deposition analysis of the reef successions can provide the basic data for oil and gas exploration and distribution of reef reservoir in the South China Sea.

关 键 词：西沙海域 生物礁序列 白云石化作用 造礁生物 西科1井 

分 类 号：TE121.3[石油与天然气工程—油气勘探]