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利用野外观察及实验数据资料,对盐津-珙县地区五峰组-龙马溪组页岩气形成条件进行分析,并探讨其富集成藏的主控因素.研究结果表明盐津-珙县地区五峰组-龙马溪组下部黑色页岩是深水陆棚沉积产物,该区页岩气“甜点段”五峰组—段—四段和龙马溪组一段—五段发育完整,有机碳质量分数在2.7%~6.0%之间,主要为中高-高有机碳含量,富有机质黑色页岩厚度分布在30~50 m.在高含气层位,纳米级有机质孔和黄铁矿晶间孔大量发育,平均孔隙度为2.28%~3.48%,为吸附气和游离气提供良好的储集空间.研究区内构造强度较弱,通天断层少,具有良好的顶底板条件,压力系数平均大于1.0,因而保存条件良好.分析表明,高有机碳含量、纳米级孔隙发育、高脆性矿物含量、高压力系数是盐津-珙县地区页岩气富集成藏的主控因素.
Based on field observations and experimental data, the formation conditions of shale gas in Wufeng Formation-Longmaxi Formation in Yanjin-Juxian area were analyzed and the main controlling factors for their enrichment and accumulation were analyzed. The results show that the Wufeng The black shale in the lower part of the Longmaxi Formation is a sedimentary product in the deep water shelf. The shale gas “sweet segment ” Wufeng Formation - segment - four segments and Longmaxi Formation - 2.7% ~ 6.0%, mainly in the high-high organic carbon content, the thickness of the organic-rich black shale ranges from 30 to 50 m. In the high-gas-bearing layers, the intergranular pores of nano-scale organic matter pores and pyrite are greatly developed , With an average porosity of 2.28% -3.48%, which provides a good storage space for adsorbed gas and free gas.The tectonic intensity in the study area is weak, there are few over-thickness faults, good top and bottom conditions, and the average pressure coefficient is greater than 1.0, thus The storage conditions are good.The analysis shows that the high organic carbon content, the development of nano-scale pores, the high brittleness mineral content and the high pressure coefficient are the main controlling factors for shale gas enrichment in Yanjin-Yixian area.