羌塘盆地羌资2井布曲组碳酸盐岩生物标志物特征及意义  

CHARACTERISTICS OF BIOMARKER COMPOUNDS IN THE MIDDLE JURASSIC CARBONATE SEQUENCE OF THE BUQU FORMATION AND THEIR IMPLICATION IN THE QIANGTANG BASIN,THE NORTHERN TIBET

作　　者：李忠雄[1,2] 何江林[3] 杜佰伟[2] 汪正江[2] 

机构地区：[1]中国地质大学资源学院,武汉430074 [2]成都地质矿产研究所,成都610082 [3]中国地质科学院研究生院,北京100037

出　　处：《石油实验地质》2010年第2期175-180,185,共7页Petroleum Geology & Experiment

基　　金：国家油气专项"青藏高原油气资源战略选区调查与评价"(XQ-2004-06)资助

摘　　要：首次报道了藏北羌塘盆地羌资2井中侏罗统布曲组海相碳酸盐岩生物标志化合物特征,该层位含有丰富的正烷烃、类异戊二烯烷烃和萜甾类化合物。正烷烃形态为单峰和双峰并存、以单峰形态占优势,主碳峰以nC17,nC20为主,次为nC18,nC15,nC16,轻烃组分占有绝对优势;OEP值介于0.37-1.14之间,平均值为0.89,无明显的奇偶优势分布;Pr/Ph值介于0.56-1.03之间,平均值为0.75,具有明显的植烷优势。萜烷相对丰度为五环三萜烷〉三环萜烷〉四环萜烷,伽马蜡烷普遍存在,但相对含量较低;甾烷主要为规则甾烷,少量孕甾烷,规则甾烷∑（C27＋C28）〉∑C29,∑C27/∑C29介于0.67-1.22之间,显示弱的C27甾烷优势或弱的C29甾烷优势。有机质母质主要来源于藻类等低等水生生物,不能确定是否有陆生高等植物输入。成熟度参数和镜质体反射率均显示碳酸盐岩处于成熟阶段。碳酸盐岩沉积环境总体为缺氧还原—弱还原的海相环境,海水盐度基本正常。Characteristics of biomarker compounds from Middle Jurassic marine carbonate sequence in Well QZ2 are reported for the first time.Abundant biomarkers,including n-alkanes,isoprenoid,steranes and terpanes,have been detected by GC-MS in this stratum.Chromatogram figure shows that n-alkanes contain nC12-nC35 with a relatively wide range,nC17,nC20,nC18,nC15 or nC16 can be as the highest peaks.Examination of the relative abundance also shows an absolute dominance of low carbon molecular components in the n-alkane.OEP ratio ranges from 0.37～1.14 with the average of 0.89.This data shows little dominance of odd-even carbon number in the alkane.Pr/Ph ratio ranges from 0.56 to 1.03 with an average of 0.75,which shows an obvious dominance of phytane in isoprenoids.The relative abundance is pentacyclic triter〉panetricyclic terpane〉quartcyclic terpane.Steranes also contain a little gammacerane.Sterpane ∑C27/∑C29 ratio ranges from 0.67 to 1.22 and this data fluctuates in the vertical carbonate sequence.Sterpane ∑（C27＋C28）〉 ∑C29 and this parameter also indicates that the organic matter is originate from algae and the contribution from terrestrial plant sources cannot be confirmed yet.Different kinds of parameters indicate that the organic matter of the whole carbonate sequence is in the mature stage.Full sedimentary environment of carbonate sequence is in the reduction condition and sea water salinity is normal.

关 键 词：生物标志化合物 有机质成熟度 布曲组 中侏罗统 海相碳酸盐岩 羌塘盆地 

分 类 号：TE122.113[石油与天然气工程—油气勘探]