林西-巴林左地区元素地球化学特征的油气示踪

Hydrocarbon Tracing of Element Geochemical Characteristics in Linxi-Balinzuo Area

为快速圈定含油气有利区段,利用1∶200000水系沉积物测量成果资料,对松辽盆地的林西-巴林左地区进行了元素地球化学分区,并对各分区的地质地球化学特征进行了分析。结果表明,研究区可分为6个地球化学区,不同分区内微量元素具有不同的元素组合特征。其中,亲铁元素(Co、V、Ni、Cr、Fe2O3、Mn、Ti)异常的分布与晚古生代地层分布基本吻合;造岩元素(CaO、MgO、Ba、Sr)异常的分布与中新生代地层基本吻合;高温元素(W、Mo、Sn、Bi)异常的展布与区内中酸性岩浆岩的分布吻合;亲铁元素(Co、V、Ni、Cr、Fe2O3、Mn、Ti)、亲硫元素(Cu、Zn、As、Sb)等在第Ⅴ地球化学区的周围形成明显的椭圆形高背景环带,在该环带所围限的区域内部构成低背景区;Ba、La、Sr等在第Ⅴ地球化学区上方形成高背景场,表明第Ⅴ地球化学区是寻找油气的有利区域。

In order to identify the favorable zone of oil and gas in Linxi-Balinzuo area of Songliao basin,the studying area are divided into several geochemical zones whose geological and geochemical characteristics are analyzed on the basis of 1∶200000 stream sediment survey material.The results are:the area can be divided into six zones,and trace elements in different zones have different element combination forms.The abnormal distribution of siderophile elements(Co,V,Ni,Cr,Fe2O3,Mn,Ti) are quite well with the later Paleozoic strata,the abnormal distribution of petrogenetic elements(CaO,MgO,Ba,Sr) are quite well with the Mesozoic and Cenozoic strata,and the abnormal distribution of high temperature elements(W,Mo,Sn,Bi) are quite well with the acid igneous rocks;Around the fifth geochemical zoning,siderophile elements(Co,V,Ni,Cr,Fe2O3,Mn,Ti) and chalcophile elements(Cu,Zn,As,Sb) form apparent oval high value band,inside of which form negative anomaly while Ba,La,Sr form positive anomaly on the top of the fifth geochemical zoning.It indicates that the fifth geochemical zone is the favorable zone of finding oil and gas.