摘要
利用岩石热解、有机碳、干酪根碳同位素、镜质体反射率及气相色谱—质谱等地球化学测试方法,分析苏北盆地海安凹陷曲塘次凹阜宁组二段烃源岩的生烃潜力及沉积环境。结果表明:曲塘次凹阜宁组二段烃源岩具有有机质丰度较高、类型好、低成熟—成熟阶段及生烃潜力强等特征。残余有机碳质量分数平均为1.77%,生烃潜量为6.20mg/g,有机质丰度较高。干酪根碳同位素为-29.2‰～-27.7‰,规则甾烷呈不对称"V"型或反"L"型分布,有机质属于Ⅱ型,具有低等水生生物和高等植物双重生源特征。镜质体反射率为0.50%～0.80%,ααα-C29(20S/(20S+20R))甾烷和ββ/(αα+ββ)-C29甾烷较低,有机质处于低成熟—成熟阶段。Pr/Ph较高,三环萜烷/C30藿烷、伽马蜡烷指数、Ts/Tm和重排甾烷C27/规则甾烷C27较低,烃源岩主要形成于弱氧化条件下的淡水—半咸水湖泊相环境,有利于有机质的保存。该研究结果为苏北盆地海安凹陷曲塘次凹下一步勘探提供参考。
Using rock pyrolysis,organic carbon,kerogen carbon isotope,vitrinite reflectance and gas chromatography-mass spectrometry,the hydrocarbon generation potential and sedimentary environment of the source rocks in Fu2 member of Qutang subsag,Haian sag,Subei basin are analyzed.The results show that in Fu2 member of Qutang subsag,the source rocks have the characteristics of high organic matter abundance,good type,low maturation to mature stage,and strong hydrocarbon generation potential.The mean value of residual organic carbon is 1.77%and hydrocarbon generation potential is 6.20 mg/g,the hydrocarbon source rocks with high abundance of organic matter.The carbon isotopes of kerogen are between-29.2‰and-27.7‰,and regular steranes is asymmetric"V"shape or"L"type distribution all reflected the organic matter belongs to typeⅡ,and the parent material has the characteristics of dual source of lower aquatic organisms and higher plants.The reflectivity of vitrinite is in the range of 0.50%~0.80%,lowerααα-C 29(20S/(20S+20R))andββ/(αα+ββ)-C 29 decane value all indicated that organic matter is in the stage of low maturity to maturity.Higher Pr/Ph value,lower tricyclic tereptane/C 30 decane value,gamma wax index,Ts/Tm value,and rearrangement decane C 27/regular decane C 27 value indicate that hydrocarbon source rocks is mainly formed in the environment of freshwater-brackish water lake under weak oxidation,contributing to the preservation of organic matter.The research results provide a reference for further exploration of Qutang subsag in Haian sag,Subei basin.
作者
胡维强
马立涛
刘玉明
李洋冰
陈鑫
柳雪青
王朵
黄英
乔方
马丽华
刘成
Hu Weiqiang;Ma Litao;Liu Yuming;Li Yangbing;Chen Xin;Liu Xueqing;Wang Duo;Huang Ying;Qiao Fang;Ma Lihua;Liu Cheng(EnerTech-Drilling and Production Company,CNOOC,Tianjin 300452,China)
出处
《东北石油大学学报》
CAS
北大核心
2018年第5期73-81,129,130,共11页
Journal of Northeast Petroleum University
基金
国家自然科学基金项目(41502132)
中国海洋石油总公司科研条件平台建设项目(CNOOC-KJPTGCJS2016-01)
关键词
烃源岩
地球化学特征
生物标志化合物
阜宁组二段
曲塘次凹
海安凹陷
苏北盆地
hydrocarbon source rocks
geochemical characteristics
biological marker compound
Fu2 member
Qutang subsag
Haian sag
Subei basin
