武威盆地石炭系烃源岩地球化学特征研究

发布时间：2018-04-22 19:44

  本文选题：武威盆地 + 石炭系　； 参考：《西安石油大学》2017年硕士论文

【摘要】：武威盆地位于河西走廊东部,是祁连—阿拉善地区石炭系发育和保存较好的地区之一,具有良好的油气地质条件。石炭系为一套海陆过渡相沉积,是盆地主要烃源岩层,石炭系地层发育完整,从下至上依次为前黑山组、臭牛沟组、靖远组、羊虎沟组和太原组,烃源岩主要为灰黑色泥、页岩和灰岩。本文通过对武威盆地野外露头剖面和探井剖面系统采样,采用有机地球化学测试技术和分析方法,建立野外露头综合地球化学剖面,对武威盆地石炭系烃源岩的有机质丰度、类型、成熟度和生物标志化合物等特征进行全面分析,并结合前人研究基础探讨盆地烃源岩有机质生源及其沉积环境。武威盆地石炭系烃源岩有机质丰度普遍较高,干酪根碳同位素组成分布于-20.1‰--26.5‰之间,有机质类型主要为Ⅲ型干酪根,少数为Ⅱ2型干酪根。不同层段烃源岩样品的最高热解峰温Tmax普遍超过了435℃,成熟度较高,处于高成熟热演化阶段。石炭系烃源岩正构烷烃以前高后低的双峰型为主,正构烷烃∑nC21-/∑nC22+主要分布在0.8-2.0之间,以饱和烃轻质组分为主,从下石炭统—上石炭统烃源岩生源从低等水生生物向陆相高等植物生源过渡。武威盆地烃源岩Pr/Ph值主要分布在0.5左右,Pr/nC17值主要分布0.53 1.0之间,Ph/nC18值主要分布范围为1.0 1.6之间,表明以植烷占优势的弱还原—还原环境为主。下石炭统的源岩以ααα20RC27甾烷占绝对优势特征,呈现正“L”型,孕甾烷类化合物含量较高,至上石炭统呈现“V”型,孕甾烷类化合物含量有所下降;C19—C23三环萜烷基本呈上升-下降-再上升趋势,Ts含量较Tm的相对含量接近,伽玛蜡烷含量较高;石炭系烃源岩菲、芘、屈类化合物含量高,而萘、蒽、惹烯、傒等多环芳香类化合物相对含量较低;芴系列化合物整体处于过渡环境,盆地石炭系沉积由还原环境向弱氧化环境过渡,生物源构成由低等水生生物向陆源高等植物过渡。
[Abstract]:Wuwei Basin is located in the eastern part of Hexi Corridor. It is one of the areas where the Carboniferous system is well developed and preserved in Qilian-Alashan area and has good oil and gas geological conditions. Carboniferous is a set of marine and continental transitional facies sedimentary, which is the main source rock in the basin. The Carboniferous strata are well developed. From the bottom to the top, they are the Qianheishan formation, the stinuigou formation, the Jingyuan formation, the Yanghugou formation and the Taiyuan formation, and the source rocks are mainly gray mud. Shale and limestone. By sampling the outcrop profile and exploration section system in Wuwei Basin, the organic geochemical testing technique and analysis method are used to establish the outcrop comprehensive geochemical profile in the field, and the abundance of organic matter in the Carboniferous source rocks in Wuwei Basin is studied. The types, maturity and biomarker compounds were comprehensively analyzed, and the source of organic matter and its sedimentary environment of source rocks in the basin were discussed based on previous studies. The abundance of organic matter in Carboniferous source rocks in Wuwei Basin is generally high, and the kerogen carbon isotopic compositions range from -20.1 鈥，

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