摘要
通过野外地质调查与室内分析测试,对湘中地区中奥陶统富有机质页岩分布、有机地球化学特征、储层特征进行研究,总结湘中地区中奥陶统烟溪组黑色页岩的地质特征。研究结果表明:研究区中奥陶统烟溪组黑色页岩分布广、厚度大(40～160 m),有机碳质量分数较高(0.87%～6.20%),普遍大于2.00%;演化程度处于成熟—过成熟阶段,干酪根类型属于Ⅰ型,页岩生气条件良好;页岩的矿物组成包括石英、长石、方解石、白云石、黏土矿物和少量黄铁矿等,其中脆性矿物质量分数为47%～87%,孔隙类型包括粒间孔、晶间孔、铸模孔、溶蚀孔、有机质孔等,属大孔至毛细孔,孔隙度为3.4%～10.8%,渗透率为(0.003～0.015)×10^(-3)μm^2,平均为0.005×10^(-3)μm^2,与四川盆地东南缘页岩气发现区的相当,具备页岩气形成的地质条件;中奥陶统烟溪组是湖南省页岩气勘探研究的新层位,其中新宁—祁东—宁远地区是有利勘探区。
Through lots of field works and laboratory tests,the geological characteristics of Yanxi Formation in this area were concluded by comprehensively investigation and analysis on the distribution and geochemical characteristics of the organic-rich marine shales and the features of reservoir.The results show that the black shales of Yanxi formation are characterized by wide distribution,great thickness(ranging from 40 m to 60 m)and high level of organic carbon(ranging from 0.87%to 6.20%),generally higher than 2.00%),the thermal maturity is at the mature to over mature stage and the kerogen belongs to typeⅠ.All of these characteristics of the black shares are beneficial for generating gas.Mineral composition of black shales include quartz,feldspar,calcite,dolomite,clay minerals and small amounts of pyrite etc.The brittle minerals percentage is from 47%to 87%.The pore types include intergranular pore,intracrystalline pore,mold pore,dissolved pore and organic pore etc.The aperture size of pores varies.The average porosity is between 3.4%and 10.8%,and the permeability of pores is(0.003?0.015)×10?3μm2 with the average permeability of pores being 0.005×10?3μm2.The characteristics are similar to those of the shale in southeast area of Sicuan basin,showing Yanxi Formation has geological conditions for the shale gas.It is a new horizon with great potential for shale gas.The area along with Xingning-Qingdong-Ningyuan can be defined as an exploration target with priority.
作者
李杰
郭建华
王宗秀
王张虎
刘辰生
LI Jie;GUO Jianhua;WANG Zongxiu;WANG Zhanghu;LIU Chensheng(School of Geoscience and Info-Physics,Central South University,Changsha 410083,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Central South University,Ministry of Education,Changsha 410083,China;Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2018年第11期2776-2786,共11页
Journal of Central South University:Science and Technology
基金
中国地质调查局地质调查项目(DD20160183)
湖南省自然科学基金资助项目(2017JJ1034)~~
关键词
湘中地区
下古生界
中奥陶统
烟溪组
页岩气
central Hunan
lower paleozoic
middle Ordovician
Yanxi Formation
shale gas
