沁水盆地石炭-二叠系煤系页岩气储层特征及生烃潜力分析——以山西省临汾市Y1井为例

Physical Characters of Coal Shale Reservoirs and Potential Analysis of Qinshui Basin—an Example from Y1 Well Linfen City,Shanxi Province

沁水盆地发育了多套煤系泥页岩,具备页岩气成藏的物质条件。为探讨沁水盆地石炭系、二叠系页岩气储层特征和勘探潜力,通过对山西临汾地区Y1井钻遇的富有机质页岩进行采样测试,利用X射线衍射、高压压汞、扫描电镜等测试方法,研究了山西省临汾地区Y1井岩芯样品的有机地球化学特征、储层物性特征和含气性特征,并对研究区页岩气的勘探潜力做了初步评价。结果表明:Y1井山西组和太原组地层基础地质条件优越,单层厚度大。页岩有机质丰度为0.28%~16.87%,平均2.15%,多数大于1%;有机质类型混源,为Ⅱ~Ⅲ型,以腐殖质为主;有机质热演化程度高,镜质组反射率为1.71%~2.10%,岩石热解峰值温度整体位于470℃左右,普遍达到高成熟阶段。页岩矿物组分以黏土矿物和石英为主,石英质量分数平均41.57%;黏土质量分数平均56.79%,主要为高岭石和伊利石。黑色页岩具有较高的含气量和吸附能力,含气量最高可达4.41 m3/t,甲烷占总气量的76%。通过烃源岩、储层和气含量等方面的结果,初步确定该区石炭系、二叠系页岩具备优质的勘探潜力。

The Qinshui Basin has developed multiple sets of coal-sediment shale,which has the material conditions for shale gas accumulation.In order to explore the characteristics and exploration potential of the Carboniferous and Permian of shale gas in the Qinshui Basin,the organic-rich shale of the Y1 well in Linfen,Shanxi was sampled and tested.By means of X-ray diffraction,high-pressure mercury injection and scanning electron microscopy etc.,the organic geochemical characteristics,reservoir physical characteristics and gas-bearing characteristics were analyzed,and the exploration potential of shale gas was initially evaluated.The results show that the basic geological conditions of the well of Y1 was excellent with a large thickness of single layer.The organic matter was 0.28%~16.87%with the average value 2.15%,and most of them more than 1%.The organic matter belonging to typeⅡand typeⅢ,was with mixed sourceand mainly humus;The organic matter was of high thermal maturity and generally of high maturity,whith the virtrinite reflectance 1.71%~2.10%,and the peak temperature of rock was above 470℃.The mineral components of shale were mainly clay minerals and quartz,and the average mass fraction of quartz was 41.57%.The average clay mass fraction was 56.79%,mainly kaolinite and illite.Black shale was of a high gas content and adsorption capacity,with gas content up to 4.41 m 3/t,and methane accounting for 76%of the total gas volume.By the analysis and results of the source rock,reservoir rock and gas content,it is clear that Carboniferous and Permian shale in this areais of great exploration potential.