柴达木盆地东北缘石炭系生物礁发育特征及其地质意义

发布时间：2018-11-08 08:25

【摘要】：对柴达木盆地东北缘石炭系地层中生物礁的发育特征及区域展布进行了系统阐述。基于野外实地考察与室内镜下分析,采用地球化学与岩石学方法相结合,总结归纳柴达木盆地东北缘石炭系生物礁的岩石学特征、生物特征以及地层特征,分析生物礁主要产出层位及规模大小,探讨其古环境与油气地质意义。研究结果表明:柴达木盆地东北缘石炭系造礁生物主要为四射珊瑚,其次为横板珊瑚,发育锥状、盘状的单体珊瑚和管状、丛状、蜂窝状的群体珊瑚,附礁生物为腕足、等;珊瑚礁在岩层中以点状产出,呈不连续带状分布,依据其在地层中的发育规律与展布特征,分为簇状竖直丛生管状珊瑚、簇状水平延伸管状珊瑚以及簇状顶端向下倾斜管状珊瑚;根据岩石中的生物颗粒含量,生物礁灰岩储层岩石类型分为珊瑚骨架灰岩、珊瑚颗粒石灰岩、生物颗粒质石灰岩、含生物颗粒石灰岩以及泥晶灰岩。柴达木盆地东北缘早石炭世以碳酸盐台地环境为主,晚石炭世以海陆交互的潮坪环境为主。研究区石炭系生物礁主要位于下石炭统怀头他拉组三、四段,在石灰沟、旺尕秀等剖面可见厚层油砂,指示柴达木盆地东北缘石炭系具有良好的生烃潜力。
[Abstract]:The development characteristics and regional distribution of reefs in Carboniferous strata in the northeastern margin of Qaidam Basin are systematically described. Based on field investigation and laboratory microscopic analysis, the petrological characteristics, biological characteristics and stratigraphic characteristics of Carboniferous reefs in the northeastern margin of Qaidam Basin are summarized by combining geochemistry and petrology. The main productive horizon and scale of the reef are analyzed, and its paleoenvironment and geological significance of oil and gas are discussed. The results show that the reef organisms of Carboniferous in the northeastern margin of Qaidam Basin are mainly Tetraeuca, followed by transverse-plate coral, conical, disklike and tubular, plexiform, honeycomb colony coral, brachiopod, etc. Coral reefs are distributed in discontinuous zones in the form of dots. According to their development and distribution characteristics, coral reefs are divided into cluster vertical tube-shaped corals. Cluster-like horizontal extended tubular corals and tube-shaped corals with tube-shaped tip and downward tilt; According to the biological particle content in the rock, the rock types of the reef limestone reservoir can be divided into coral skeleton limestone, coral granular limestone, biological granular limestone, biogranular limestone and marl limestone. In the northeast margin of Qaidam Basin, the carbonate platform environment was dominant in the early Carboniferous and the tidal flat environment in the late Carboniferous. Carboniferous reefs are mainly located in the third and fourth member of Huitoutala formation of Lower Carboniferous in the study area. Thick oil sand can be seen in the sections of Limegou and Wanggarxiu, indicating that Carboniferous has good hydrocarbon generation potential in the northeast margin of Qaidam Basin.
【作者单位】：中国石油大学(华东)地球科学与技术学院;
【基金】：中国地质调查局地质调查项目(12120115003301)~~
【分类号】：P618.13

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