燕山地区中元古界页岩气成藏地质条件

Geological conditions of the Mesoproterozoic shale gas accumulation in Yanshan area,North China

燕山地区发育中元古界洪水庄组和下马岭组2套富有机质泥页岩,勘探程度低,页岩气资源的勘探潜力不明。对河北怀来、宽城和北京十三陵等地区开展野外地质调查,并对冀元1井、冀浅1井和京101井的中元古界黑色页岩开展岩心观察和实验分析,研究了洪水庄组和下马岭组黑色页岩的沉积相分布、有机质丰度、有机质类型、热成熟度、孔渗性和岩石矿物特征等页岩气成藏地质条件。研究表明,燕山地区洪水庄组和下马岭组的页岩厚度大、有机质含量高、热演化程度适中、生烃时间晚、受晚期构造活动破坏作用小,具备良好的页岩气成藏地质条件;河北承德—宽城一带稳定构造带为勘查洪水庄组页岩气的有利区;河北涿州—北京房山—门头沟—昌平一带和河北兰旗营子一带稳定的构造带为勘查下马岭组页岩气的有利区。

Two sets of organic-rich shale are developed in Yanshan area,including Mesoproterozoic Hongshuizhuang Formation and Xiamaling Formation.Because of low exploration level,the exploration potential of these shale gas resource is unknown.Based on the field geological survey in the Huailai county and Kuancheng county of Hebei province and the Ming Tombs area of Beijing,and the observation and experimental test of Mesoproterozoic black shale cores in Wells Jiyuan-1,Jiqian-1 and Jing-101,the geological conditions of shale gas accumulation in black shale of Hongshuizhuang Formation and Xiamaling Formation are studied,including the sedimentary facies distribution,abundance and type of organic matter,thermal maturity,porosity,permeability and rock mineral features.Research result shows that the shale in Hongshuizhuang Formation and Xiamaling Formation is characterized by large thickness,high organic matter content,moderate thermal evolutionary degree,late hydrocarbon generation,little destructive effect from late tectonic activity,and favorable accumulation geological conditions.The shale gas favorable area for Hongshuizhuang Formation is in the stable tectonic zone from Chengde to Kuancheng of Hebei province;and the area for Xiamaling Formation is in the stable tectonic zone from Zhuozhou of Hebei province to Fangshan,Mentougou and Changping of Beijing,as well as in the Lanqiyingzi area of Hebei province.