摘要
孙吴-嘉荫盆地沾河断陷的主力烃源岩是淘淇河组,属中等烃源岩;有机质类型为Ⅱ2和Ⅲ型;有机质成熟度处于低成熟-成熟阶段。烃源岩抽提物生物标记化合物组成中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。正构烷烃呈单峰型分布,nC23、nC27、nC29为主峰碳,重烃组分占有绝对优势,OEP值为1.04～3.76,具有明显的奇碳数优势。Pr/Ph比值为0.49～2.31,多数接近于1,姥鲛烷和植烷优势不明显。萜烷主要为五环三萜烷,以C30藿烷和C31升藿烷丰度最高,其次是C29降藿烷和Tm;甾类化合物主要成分为规则甾烷C27、C28和C29,ααα20RC27、C28和C29甾烷多数呈不对称的"V"形分布,C29>C27>C28。甾萜烷分布特征反映了孙吴-嘉荫盆地沾河断陷淘淇河组烃源岩的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,其沉积环境为弱氧化弱还原环境。
The source rock of taoqihe formation is main and might belong to middle one in Zhanhe Fault-De- pression , Sunwu-Jiayin Basin. There are two types of organic matters in the source rock （ II 2 and II1 types）. The source rock are in the lower-maturity and maturity stage. The biomarker combinations included n-alkanes, isopre- noid, terpanes and steranes. The n-alkanes showed a dominance of high carbon molecular components with highest peaks of nC23, nC27 or rtC29. OEP values of the n-alkanes showed obvious odd carbon dominance. Pr/Ph ratios were 0.49 - 2.3 1 and were close to 1 ,which indicated the source rock no possessing apparent pristine and phytane dominance. The terpanes distribution patterns of the source rock samples are mainly pentacyclic triterpane, which consisted mainly of C30-hopanoid and subordinate C31-homohopane, C29-norhopane and Tm according to abundance. The steranes consisted mainly of C27-steranes, C2s-steranes, C29-steranes, and the abundance of C29 〉 C27 〉 C28. All these biomarker＇ s characteristics indicated the organic matters of the source rock of taoqihe formation should be of algae origin, with proper contribution from terrestrial higher plant.
出处
《科学技术与工程》
北大核心
2013年第1期28-33,共6页
Science Technology and Engineering
基金
国家重点基础研究发展计划项目(2006CB701403)资助
关键词
孙吴-嘉荫盆地
沾河断陷
淘淇河组
烃源岩地球化学特征
生物标志化合物特征
Sunwu-Jiayin basin Zhanhe fault-depressoonteristics of source rock biomarkers characteristicsTaoqihe formation geochemical charac-
