鄂尔多斯盆地黄陵北部延安组页岩气勘探潜力分析

Analysis of shale gas resource exploration potential of Yan'an Formation in northern Huangling mining area of Ordos basin

  • 摘要: 鄂尔多斯盆地中南部发育有侏罗系延安组第二段和第三段陆相暗色厚层泥岩层系,矿物成分以石英、黏土为主,石英43%~56%,黏土矿物29%~33%。总有机碳(TOC)1.63%~3.89%,有机质成熟度Ro为0.59%~0.60%,含气量(CH4)0.25~0.85 m3/t,等温吸附实验表明延安组泥岩的甲烷吸附能力与总有机碳含量呈正相关关系。泥岩处于生物成因气阶段,具备页岩气形成的基本地质条件,并可对比美国密歇根盆地Antrim页岩和伊利诺斯盆地的New Albany页岩的地质条件。为查清黄陵北部侏罗系延安组页岩气的勘探潜力,通过分析勘查和化验测试资料,对其页岩气勘探潜力进一步评价认为:黄陵北部延安组泥岩分布范围和厚度较大,已进入生物成因气和热催化生气的中间阶段,有机质丰度较高,具备形成页岩气的成藏条件,页岩气潜力巨大。

     

    Abstract: Ordos basin is one of the important energy resource basins in China. The second and third members of Jurassic Yan'an Formation in northern Huangling mining area of the south-central Ordos basin contain a thick succession of continental dark mudstone. The minerals of the mudstone are dominated by quartz and clay minerals, with quartz content 43%~56%, clay content ranging 29%~33%. The total organic carbon (TOC) content of the mudstone is 1.63%~3.89%, the organic maturity is characterized by Ro of 0.59%~0.60%, and gas (CH4) content is 0.25~0.85 m3/t. The isothermal adsorption test showed that gas adsorption capacity of the mudstones in Yan'an Formation had a positive correlation with TOC. The gas is biogenic and possessed the basic geological conditions of shale gas formation. The characteristics of the mudstone can be compared with New Albany Shale in Michigan basin and Antrim Shale in Illinois basin of America. In order to assess the shale gas resource potential of Yan'an Formation in northern Huangling mining area, the exploration data and laboratory experiment data were analyzed. A preliminary assessment of gas resources demonstrated that the mudstone in Yan'an Formation in northern Huangling mining area has broad distribution and big thickness, and is characterized by high TOC content and high gas production potential. On the whole, the shale gas potential is very good.

     

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