鄂西地区下寒武统牛蹄塘组页岩气保存条件研究  

A study on shale gas preservational conditions of the Lower Cambrian Niutitang Formation in the Western Hubei

作　　者：许露露 周向辉 陈威 任志军 温雅茹 文剑航 罗凡 王亿 谢通 段轲 杨洁 XU Lulu;ZHOU Xianghui;CHEN Wei;REN Zhijun;WEN Yaru;WEN Jianhang;LUO Fan;WANG Yi;XIE Tong;DUAN Ke;YANG Jie(Hubei Geological Survey,Wuhan,Hubei 430034,China;不详)

机构地区：[1]湖北省地质调查院

出　　处：《海相油气地质》2021年第2期113-122,共10页Marine Origin Petroleum Geology

基　　金：湖北省自然资源厅科研项目“鄂西地区下古生界页岩气储层物性特征及差异富气机理研究”(编号:ZRZY2020KJ10);湖北省地质局科研项目“鄂西地区构造特征与页岩气保存条件研究”(编号:KJ2019-3);湖北省自然资源厅地调项目“湖北省页岩气勘查区块评价优选”(编号:HBCZ-17060223-170397)联合资助。

摘　　要：下寒武统牛蹄塘组是鄂西地区重要的页岩气勘探目的层系。利用鄂西地区调查井及野外露头资料,对牛蹄塘组岩石地层及沉积相特征、含气性特征及页岩气保存条件等进行了分析,并对页岩气成藏有利区进行了综合评价。研究表明:鄂西地区牛蹄塘组纵向上可以分为2段,其中下部的牛蹄塘组一段发育深水泥质陆棚相黑色碳质页岩,是主要的页岩气含气层段。纵向上,牛蹄塘组一段现场解吸气含量从顶到底逐渐增加,往下至岩家河组又急剧变小。平面上,含气性较好的地区主要位于黄陵背斜东南缘深水陆棚相区。指出页岩气富集成藏必须满足以下条件:深水陆棚相区,褶皱宽缓;距离区域性正断层超过5km;岩心裂隙密度小且高角度裂隙不发育;顶底板封闭性良好,地层连续无沉积缺失;R_(o)小于3.0%;埋深大于500m。评价预测的有利区块主要分布在黄陵背斜东南缘,仙女山断裂以东、雾渡河断裂西南、通城河断裂以西的区域。The Lower Cambrian Niutitang Formation is an important shale gas exploration target in the Western Hubei.Based on the data of survey wells and outcrops in the Western Hubei,the rock formation,sedimentary facies,gas-bearing characteristics and shale gas preservational conditions of Niutitang Formation are analyzed,and the favorable areas for shale gas accumulation are comprehensively evaluated.The results show that the Niutitang Formation(∈1n)can be divided into 2 sections(∈1n1and∈1n2)vertically,and the lower part(∈1n1)develops black carbonaceous shale of deepwater argillaceous shelf facies,which is the main shale gas bearing interval.Vertically,the field canister desorption gas content of the Niutitang Member 1 gradually increases from top to bottom,and decreases sharply down to the Yanjiahe Formation.On the plane,the area with good gas bearing property is mainly located in the deep-water shelf facies in the southeast margin of Huangling anticline.It is pointed out that the favorable area of riching in shale gas must meet the following conditions:deep water shelf facies;fold being gentle and wide;more than 5 km away from regional normal fault;low core fracture density and undeveloped high angle fractures;good sealing of roof and floor,continuous and no sedimentary loss in formation;R_(o) less than 3.0%;buried depth greater than 500 m.The favorable blocks are mainly located in the southeast margin of Huangling anticline,the area of east of Xiannüshan fault,southwest of Wuduhe fault and west of Tongchenghe fault.

关 键 词：页岩气 含气性 保存条件 有利区评价 牛蹄塘组 鄂西 

分 类 号：TE132.2[石油与天然气工程—油气勘探]