川南二叠系阳新统大断裂封闭性研究

STUDY ON THE SEALING PERFORMANCE OF MAJOR FAULTSIN THE YANGXIN SERIES OF THE PERMIAN, SOUTH SICHUAN AREA

在大断裂带及其附近能形成较大的储集空间,问题在于其是否封闭及封闭程度如何。文中讨论了大断裂带的成藏可能性,提出了识别断层是否封闭的3个判别标志:a)高异常地层压力;b)代表封闭环境的水型与高矿化度;c)纵向上的多产层、多压力系统与多种水型。这3个判别标志不仅适用于川南二叠系这样的碳酸盐岩地区,也适用于其它碎屑岩沉积区。川南地区除"通天"断层和膏盐层被剥蚀地区外,不少隐伏于地下的大断裂具良好封闭性,有利于油气的运移、聚集和保存。

Larger storage spaces can be formed within and nearby major faulted zones. The problem is if and in what degree they are sealing. In this paper, the pool forming probability of major faulted zones was discussed, and three signs used to discern a fault is sealing or not were suggested, that is, a)high abnormal formation pressure, b) water types and mineralization degree representing sealing environments and c) longitudinal multiple pay beds, pressure systems and water types. The three signs for discernment are fit for not only carbonate rock regions such as the Permian of South Sichuan area but also other clastic rock sedimentary regions. Except for the Tongtian Fault and denuded regions of gypsum salt layers in South Sichuan area, many major faults buried underground have good sealing performance and are favorable for the migration, accumulation and preservation of oil and gas.