榆树林油田扶杨油层沉积岩地球化学特征及地质意义  

Geochemical Characteristic of Sedimentary Rocks in the Fuyang Oil Layer of Yushulin Oil Field and Its Geological Significance

作　　者：施秋华 袁亚娟[1,2] 夏斌 林舸[3] 

机构地区：[1]中山大学海洋学院,广州510275 [2]海洋石油勘探与开发广东高校重点实验室,广州510275 [3]中国科学院广州地球化学研究所,广州510640

出　　处：《地质学报》2018年第1期154-169,共16页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号41372208;40534019)资助的成果

摘　　要：三肇凹陷榆树林油田扶杨油层中泥岩、粉砂岩和砂岩样品主量元素和微量元素地球化学分析表明,多数主量元素含量中等,与全球平均大陆上地壳(UCC)相比,Fe_2O_3、MgO、CaO、Na_2O含量较低,而TiO_2、Al_2O_3、K_2O、MnO含量均略高;样品中的相容元素(V、Cr、Co、Ni等)含量均低于澳大利亚后太古宙页岩(PAAS)和UCC;稀土元素总量为102×10^(-6)~276×10^(-6),平均为188×10^(-6),与PAAS表现出相似的球粒陨石标准化曲线,显示了相似的物源和构造背景。元素间的相关性分析显示大部分元素与SiO_2负相关而与Al_2O_3正相关,说明大部分元素受到黏土矿物吸附作用的影响,石英与长石矿物对这些元素表现出一定的稀释效应。根据主元素物源判别方程图和Th-Hf-Co图投影及La/Hf、(Gd/Yb)N值,扶杨油层物源主要来自后太古宙长英质火山岩,可能卷入了部分再循环沉积岩。通过一系列的构造背景判别图解分析,表明扶杨油层沉积时以大陆岛弧环境为主。在对油层组进行了纵向古气候分析后,认为FI油层组沉积时处于一个构造活动强、干旱的环境中,所形成的沉积岩储层物性更好,是油气勘探开发的重点层位。The study conducted geochemical analyses of mudstone, siltstone and sandstone samples from the Yushulin Oilfield, Sanzhao sag. The results show that the most of major elements have moderate contents. Compared with the average of upper continent crust （UCC）, the samples have lower Fe2 O3, MgO, CaO and Na2O, but slightly higher TiO2, Al2O3, K2O, MnO. The contents of compatible elements （V, Cr, Co and Ni） in the samples are lower than PAAS （Post Archean Australian shale） and UCC, and the total amount of REEs ranges from 102×10^-6 to 276×10^-6 with an average of 188×10^-6. The similar chondrite-normalized REE pattern with PAAS suggests that they have similar provenance and tectonic settings. The Pearson correlation of some elements shows that most elements are negatively related to SiOz but positive to Alz O3, indicating that most elements are affected by clay minerals because quartz and feldspar exert a dilution effect on these elements. Based on the provenance discrimination diagram of major elements, Th-H[-Co plot, and La/Hf and （Gd/Yb）N, it can be concluded that the provenance of studied area mainly derived from felsic-predominant rocks, probably involved in some recycle sedimentary rocks. A series of tectonic discrimination diagrams suggests that the Fuyang oil layers deposited in a continent island arc setting. Pale-climate analysis of oil sub-layers shows that FI sub-layer deposited in a strong tectonic activity settings and drought climate and is of better reservoir physical properties. Therefore, this should be the key layers for oil and gas exploration.

关 键 词：扶杨油层 沉积地球化学 构造背景 物源 

分 类 号：P618.13[天文地球—矿床学]