鄂尔多斯盆地富县地区长7页岩气勘探潜力分析

Shale Gas Exploration Potential of Chang 7 in Fuxian Area,Ordos Basin

鄂尔多斯盆地是大型富含油气盆地,发育多套页岩层系,具备页岩气成藏的物质基础。为查明鄂尔多斯盆地富县地区长7页岩气的勘探潜力,本文在区内及邻区老井复查、岩心观察的基础上,利用有机地球化学和岩石学分析、含气量测试等多种手段,分析了长7页岩的基本特征、地化及含气性特征。在此基础上,对长7页岩气勘探潜力作了初步评价。结果表明,长7页岩埋深和厚度适中,有机质具有混合型的特点,且以Ⅱ1型为主,有机质含量高;岩石中脆性矿物石英含量不低,裂缝发育;长7全段含气量较高,其中以长73最优,可达6. 63 m3/t,是长7页岩气勘探的有利层位;研究区内泥页岩厚度大、含气量高的张家湾和直罗地区为页岩气勘探的有利区。

As a large -sized petroliferous basin with many shale formations, the Ordos basin has the material basis for shale gas development. In order to evaluate the shale gas exploration potential of Chang 7 formation, the authors investigated the geological and geochemical characteristics of Chang 7 formation with the aid of organic geochemical and petrologic analysis, gas quanitity test. On such a basis, the preliminary evaluation of Chang 7 formation shale gas exploration potential was carried out. The result showed that the Chang 7 formation shale has moderate burial depth and thickness, with high abundance of organic matters and mixed character which is mainly of Ⅱ1 type, with low content of brittle mineral quartz and much fracture. The Chang 7 formation intact gas content is high, which is the Chang 73 optimal, the maximum gas quantity could be up to 6.63 m^3/t, that is favourable for the formation of Chang 7 shale gas exploration. The favorable targets lie in the Zhangjiawan and Zhiluo area which has thicknese shale, high gas content.