湘中地区下古生界烟溪组页岩气资源潜力评价

Evaluation of shale gas resources potential of Lower Paleozoic Yanxi Formation in central Hunan Province

湘中地区烟溪组发育巨厚层未变质的碳质页岩,但目前对其生烃潜力的研究尚少。文中以湘中地区烟溪组暗色页岩为研究对象,综合运用有机地球化学、X射线衍射、扫描电镜、高压压汞等实验方法,对页岩有机地球化学特征、储层物性特征及页岩气开发有利区进行了分析。结果表明:湘中地区烟溪组页岩有机地球化学特征、储层物性特征都较好,其中有机碳质量分数高、有机质成熟度适中、脆性矿物质量分数高、储层孔隙发育、渗透性良好;采用权重分析法,得到湘中地区页岩气勘探有利区分布在双牌区块和零陵区块,并在这2个区块内优选了重点勘探区域。

At present, the research of the hydrocarbon generation potential of the unmetamorphosed carbonaceous shale of the developed super thick strata of Yanxi Formation in central Hunan Province is rarely touched. Taking the dark shale of Yanxi Formation in central Hunan Province as the object of study, this paper analyzes the organic geochemical characteristics, reservoir physical characteristics of the shale and the development of the shale gas by the comprehensive using of experimental methods such as organic geochemistry, X-ray diffraction, scanning electron microscope, high pressure Hg injection, and so on. The results indicate that the organic geochemical characteristics and reservoir physical characteristics of the shale of Yanxi Formation in central Hunan Province are relatively good, including the high rate of the organic carbon, the moderate maturity of the organic matter, the high rate of the brittle mineral, and the good development and permeability of the reservoir porosity. It is also found that the favorable areas for shale gas exploration in central Hunan area are in Shuangpai Block and Lingling Block by adopting weight analysis, and the areas for major exploration are selected within these two blocks.