南黄海盆地崂山隆起中南部海底沉积物饱和烃类地球化学特征与热成因烃类输入  

Geochemistry of saturated hydrocarbons and thermogenic hydrocarbon input in seabed sediments from the south central Laoshan uplift in South Yellow Sea Basin

作　　者：李双林[1,2] 赵青芳 王建强[1,2] 董贺平 LI Shuanglin;ZHAO Qingfang;WANG Jianqiang;DONG Heping(Qingdao Institute of Marine Geology,CGS,Qingdao 266071,Shandong,China;Laoshan Laboratory,Qingdao 266237,Shandong,China)

机构地区：[1]中国地质调查局青岛海洋地质研究所,山东青岛266071 [2]崂山实验室,山东青岛266237

出　　处：《地质通报》2023年第5期669-679,共11页Geological Bulletin of China

基　　金：崂山实验室科技创新项目《中国海域重点盆地发育时空差异及其深部过程》(编号:LSKJ202203401);中国地质调查局项目(编号:DD20221723);国家自然科学基金项目《南黄海崂山隆起中南部海底渗漏烃类源区示踪与运移路径重建》(批准号:41776075);《南黄海崂山隆起二叠系储层油气成藏破坏与流体演化过程还原研究》(批准号:42076220);山东省基金项目《南黄海盆地崂山隆起海底烃类渗漏成因及其三维模型构建》(编号:ZR2019BD067);山东省自然科学基金面上项目《南黄海盆地崂山隆起石炭系油气保存条件的主控因素分析》(编号:ZR2020MD071)。

摘　　要：通过有机地球化学方法研究南黄海崂山隆起中南部海底表层沉积物的饱和烃地球化学特征,分析其与深部油气的关系。南黄海盆地崂山隆起中南部25个站位海底沉积物的正构烷烃色谱图呈前峰型和后峰型2种类型分布,其中一些站位海底沉积物的正构烷烃色谱图存在明显的难溶复杂化合物“UCM”鼓包,指示这些站位的海底沉积物可能有热成因烃类输入并受到生物降解。海底沉积物藿烷系列在m/z191质量色谱图上呈现地质构型、生物构型及混合构型,其中地质构型为主的站位海底沉积物Ts/Tm和C_(31)升藿烷22S/(22S+22R)指示有机质成熟度高,表征有外来高成熟度热成因烃类的输入。一些站位的20S/(20S+20R)-C_(29)甾烷与αββ/(ααα+αββ)-C_(29)甾烷参数反映海底沉积物中有机质的成熟度达到成熟,明显偏离了现代沉积物未熟-低熟的特征,也表明有外来成熟热成因烃输入。南黄海崂山隆起中南部海底沉积物有机质主要有3种来源,包括陆源有机质、海洋内源有机质和热成因烃类输入有机质。深部油藏沿边界断裂和地层之间不整合面向海底表面渗漏是海底沉积物热成因烃类输入的主要机制。The geochemical characteristics of saturated hydrocarbon in the surface sediments of the southern central Laoshan uplift in the South Yellow Sea Basin were studied by organic geochemistry method and the relationship between saturated hydrocarbon and deep oil and gas was analyzed.The n-alkane chromatograms of seabed sediments from 25 sites show two types of distribution:front peak and back peak in the south central Laoshan uplift of the South Yellow Sea Basin.Some of chromatograms exist distinct"UCM"bulges,which indicate that there may be theromgenic hydrocarbons imported into seabed sediments and suffer biodegradation in these sites.In m/z191 mass spectrogram,the hopane series of seabed sediments exhibit geological,biological and mixed configurations,in which Ts/Tm and C_(31)-litre hopane 22S/(22S+22R)indicate high thermal maturity of organic matter,also mean the importation of exogenous thermogenic hydrocarbons with high thermal maturity.The 20S/(20S+20R)-C_(29)andαββ/(ααα+αββ)-C_(29)steroids parameters of seabed sediments at some sites reflect that the maturity of organic matter has reached maturity,which is obviously deviated from the immature-low maturity characteristics of modern sediments,and also indicates the importation of exotic high maturity thermogenic hydrocarbons.The three main sources of organic matter including terrigenous organic matter,marine endogenous organic matter and thermogenic hydrocarbon input in seabed sediments in the south central Laoshan Uplift of the South Yellow Sea.The vertical seepage of deep reservoirs along boundary faults and unconformity in strata towards the seafloor is the main mechanism of thermogenic hydrocarbon input of seabed sediments.

关 键 词：南黄海盆地 崂山隆起 饱和烃类 热成因烃类输入 海底沉积物 

分 类 号：P736.21[天文地球—海洋地质]