四川盆地膏盐岩层对页岩气保存及勘探前景的影响

Impact of Gypsolith on the Preservation and Exploration Prospect of Shale Gas in Sichuan Basin

通过调研分析前人研究结果与收集统计大量钻井及地球物理资料,探讨四川盆地膏盐岩层对页岩气保存的影响以及龙马溪组页岩气勘探潜力。结果表明:四川盆地下寒武统与三叠系膏盐岩滑脱层在构造变形中起重要的控制作用,是形成盆地内不同构造形态的主要因素,对四川盆地龙马溪组页岩气的保存有着重要作用。膏盐岩层有利于其下部地层异常压力的形成,对页岩气的成藏和保存有重要影响。膏盐岩层是影响四川盆地龙马溪组页岩气勘探前景的重要控住因素之一。综合考虑膏盐岩层分布、页岩埋藏深度、地层厚度与地球化学条件等因素,认为四川盆地龙马溪组页岩气勘探优选区域为自贡—宜宾区域、重庆—永川区域、涪陵区域。

Based on the analysis of previous researches and drilling data,this paper interpreted the impact of gypsolith on the preservation and exploration prospect of shale gas in Sichuan Basin.Results show that the halite layer of Lower Cambrian and Triassic plays an important controlling role in tectonic deformation,resulting in different structural styles in Sichuan Basin.The formation under gypsolith tends to be overpressure because of the halite layer.Gypsolith in Sichuan Basin is one of the most important factors which controls the shale gas exploration of Longmaxi Formantion.Based on the distribution of salt layers,depth and thickness of shale,and organic geochemical characteristics,we suggest that Zigong-Yibin,Chongqing-Yongchuan,and Fuling are the favorite shale gas exploration regions in Sichuan Basin.