松辽盆地北部上白垩统油页岩地球化学特征及沉积环境初探  

A preliminary study on geochemical characteristics and depositional environments of oil shale in the northern Songliao Basin

作　　者：姜丽娜[1] 陈春瑞[1] 杨建国[1] 

机构地区：[1]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《地质科学》2009年第2期457-467,共11页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家重点基础研究发展计划(编号:2009CB219308)资助

摘　　要：松辽盆地北部上白垩统油页岩属中-差油页岩;有机质类型以Ⅰ型为主,Ⅱ_1型为辅,处于低成熟—成熟阶段。生物标记化合物都含有丰富的正构烷烃、类异戊二烯型烷烃、萜类化合物和甾类化合物。正构烷烃呈前高后低的单峰型分布,nC_(23)、nC_(27)为主峰碳,重烃组份占绝对优势,OEP值为1.02～6.63,具有明显的奇碳数优势。Pr/Ph比值为0.13～1.37,多数小于0.6,具植烷优势,伽马蜡烷含量较高,油页岩沉积环境为咸化还原环境且盐度较高。萜烷丰度顺序为五环三萜烷>三环萜烷,三环萜烷中C_(20)、C_(21)和C_(23)丰度相对较高,且C_(20)、C_(21)和C_(23)多呈倒"V"形分布,C_(23)相对富集。甾类化合物主要成份为规则甾烷C_(27)、C_(28)和C_(29),ααα20RC_(27)、C_(28)和C_(20)甾烷多数呈儿乎对称的"V"形分布,C_(29)>C_(27)>C_(28)。甾萜烷分布特征反映其原始有机母质构成中既有丰富的菌藻类等低等水生生物,又有一定比例的陆生高等植物混合输入。The Upper Cretaceous oil shale in the northern Songliao Basin might belong to middle and relatively bad one. There were two types of organic matters in the oil shale（ Ⅰ and subordinate Ⅱ 1 types）. The oil shale was in the lower-maturity stage, and the maturity of the oil shale in Qingshankou Formation was higher than that of Nengjiang Formation. The biomarker combinations,including n-alkanes, isoprenoid, terpanes and steranes, were similar in the both formations. The n-alkanes showed a dominance of high carbon molecular components with the highest peaks of nCz3 or nC27. OEP values of the n-alkanes showed obvious odd carbon dominance. Pr/Ph ratios were 0. 13 -1. 37 , which indicated the oil shale possessing phytane dominance. There was a higher abundance of gammacerane in the oil shale. The biomarker＇s parameters reflected that the depositional environment should be reduction condition,with high salinity. The terpanes distribution patterns of oil shale samples were pentacyclic terpanes 〉 tricyclic terpanes. The terpanes consisted mainly of C20-tricyclic terpanes, C21-tricyclic terpanes and C23- tricyclic terpanes. According to abundance of C23 〉 C21 ,the steranes consisted mainly of C27- steranes, C28-steranes and C29-steranes, and the abundance of C29 〉 C27 〉 C28. All these biomarker＇s characteristics indicated that the organic matters of the Upper Crataceous oil shale in the northern Songliao Basin should be of algae origin,with proper contribution from terrestrial plant.

关 键 词：油页岩 含油率 地球化学特征 沉积环境 上白垩统 松辽盆地北部 

分 类 号：TE132.8[石油与天然气工程—油气勘探]