重庆黔江地区下寒武统牛蹄塘组页岩气成藏条件

发布时间：2018-07-02 19:58

本文选题：重庆黔江 + 牛蹄塘组　；参考：《地质科技情报》2017年03期

【摘要】：下寒武统牛蹄塘组是重庆黔江地区继下志留统龙马溪组之后,最有望取得页岩气勘探突破的重点层系之一,但其页岩气勘探方向仍不明确。通过钻井岩心和野外露头剖面观察,采用显微薄片、扫描电镜、全矿物-黏土矿物X衍射、有机地球化学参数等多项实验测试方法,系统分析了区内牛蹄塘组沉积环境、富有机质页岩的分布与埋深及其有机地球化学指标、储集性特征、保存条件与含气性特征等页岩气成藏条件。研究表明区内牛蹄塘组处于浅水陆棚-深水陆棚过渡沉积环境,富有机质页岩分布于地层下部,沉积厚度40~80m;有机碳质量分数介于2.0%~6.0%,热演化程度达过成熟阶段,有机质类型以Ⅰ型为主,生烃强度5×10~8~20×10~8 m~3/km~2,生烃潜力较大;脆性矿物含量较高,黏土矿物以伊利石和伊/蒙混层为主,页岩储层储集空间类型多样,具低孔-超低渗特征,具备了页岩气藏发育的良好地质条件。综合各种页岩气选区评价指标表明,黔江-濯水-酉阳以西、彭水以东、北抵郁山-黔江、南至洪渡-酉阳等区域的牛蹄塘组页岩气成藏条件优越,为区内页岩气勘探有利区带。
[Abstract]:The Niutetang formation of Lower Cambrian is one of the key strata in Qianjiang area of Chongqing after the Longmaxi formation of Lower Silurian, but the direction of shale gas exploration is still unclear. Through observation of drilling core and outcrop profile, the sedimentary environment of Niutetang formation in this area was systematically analyzed by means of microsheet, scanning electron microscope, X-ray diffraction of whole mineral-clay minerals, organic geochemical parameters and so on. The distribution and buried depth of organic shale and its organic geochemical indexes, reservoir characteristics, preservation conditions and gas-bearing characteristics of shale gas accumulation. The results show that Niulitang formation is in the transitional sedimentary environment of shallow-water shelf and deep-water shelf, the rich organic matter shale distributes in the lower part of the stratum, the sedimentary thickness is 40 ~ 80m, the mass fraction of organic carbon is between 2.0 ~ 6.0cm, and the thermal evolution degree is over mature. The main types of organic matter are type I, the hydrocarbon generation intensity is 5 脳 10 ~ (8) ~ 20 脳 10 ~ (-8) m ~ (-1), the hydrocarbon generation potential is large, the content of brittle minerals is relatively high, the clay is dominated by Illite and Iraq / Mongolia, and the reservoir space of shale reservoir is diverse, and it is characterized by low porosity and ultra-low permeability. It has good geological conditions for the development of shale gas reservoir. The comprehensive evaluation indexes of shale gas district indicate that the conditions of shale gas accumulation of Niutetang formation in Qianjiang, Zhuanshui-Youyang, east of Pengshui, Yushan-Qianjiang in the north and Hongdu-Youyang in the south are superior. It is a favorable zone for shale gas exploration in this area.
【作者单位】：中国地质调查局成都地质调查中心;国土资源部沉积盆地与油气资源重点实验室;
【基金】：中国地质调查局项目“四川盆地下古生界海相页岩气基础地质调查”(121201010000150004)
【分类号】：P618.13

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