鄂尔多斯盆地西缘推覆带上古生界天然气成藏地球化学特征  

GEOCHEMICAL CHARACTERISTICS OF UPPER PALEOZOIC NATURAL GAS ACCUMULATION IN NAPPED BELT,WESTERN MARGIN OF ORDOS BASIN

作　　者：李剑锋[1] 孙林[1] 马军[1] 昝川莉[1] 

机构地区：[1]长庆油田分公司勘探开发研究院,陕西西安710021

出　　处：《天然气地球科学》2007年第3期436-439,共4页Natural Gas Geoscience

摘　　要：鄂尔多斯盆地西缘推覆带上古生界天然气为非烃类组分含量相对较低、烃类烃组分含量相对较高的煤成气。根据上古生界太原组有机质RO值平面、纵向上的分布,结合构造演化特征,认为天然气的生成、成藏应晚于推覆构造发生的时间——晚侏罗纪,且烃类以垂向运移为主。根据天然气地化特征纵向变化,认为天然气成藏具有同期次性或运移的均衡性特征,烃源岩较强的排烃能力造成天然气甲烷碳同位素偏重。The Upper Paleozoic natural gas in the napped belt of the western margin of the Ordos basin is coal measure gas with lower non-hydrocarbon and higher hydrocarbon component concentrations. Based on the horizontal and vertical distribution of the Ro values of organic materials in the Taiyuan Formation, together with the evolvement characteristics of the tectonics, it is considered that the formation and accumulation of the natural gas are later than the occurrence of the napped belt （Late Jurassic）, and the hydrocarbon mainly migrates vertically. The vertical change of the natural gas geochemical characteristics indicates that the accumulation is characterized by contemporaneous formation and balanced migration. The strong capability of hydrocarbon expulsion causes carbon isotopes of methane in natural gas relatively heavy.

关 键 词：鄂尔多斯盆地 上古生界 天然气 地球化学 

分 类 号：TE122.113[石油与天然气工程—油气勘探]