对岩石薄片镜下鉴定和阴极发光等分析表明，鄂尔多斯盆地中西部奥陶纪的热液活动在岩石学上的特征有：出现热液成因凝灰岩、马鞍状白云石、斑块状黄铁矿、自生石英、石英-萤石和天青石-方解石的热液矿物组合，白云石在阴极发光下呈昏暗色。发现热液流体活跃区域与西缘断裂带走向一致，受热液影响的储层孔隙度较其他储层孔隙度平均值高出2%~3%左右。认为研究区热液活动对奥陶系储层起着建设性作用，受热液影响的储层可作为油气勘探的有利目标之一。%The analysis of thin sections and cathode luminescence for core samples has shown several petrological characteristics of Ordovician hydrothermal activities in the central and western parts of Ordos Basin. The hydrothermal products commonly are hydrothermally-origined tuff, saddle dolomite, mottled pyrite and authigenic quartz and some hydrothermal mineral assemblages including quartz-fluorite and lapis lazuli-calcite, in which the hydrothermally-origined dolomite shows dark color in cathode luminescence. It is discovered that the strike of the hydrothermally active field follows the trend of faults in the western margin of the basin and the average porosity of hydrothermally-influenced reservoirs is 2%~3% higher than that of general reservoirs. It is concluded that hydrothermal activities play a constructive role in the Ordovician hydrothermal reservoirs, which are expected to be one of the most favorable exploration targets.
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