摘要
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。讨论了大断裂带的成藏可能性,提出识别断层是否封闭的三个判别标志:(1)高异常地层压力;(2)代表封闭环境的水型与高矿化度;(3)纵向上的多产层、多压力系统与多种水型。这三个判别标志不仅适用于川南二叠系这样的碳酸盐岩地区,也适用于其他碎屑岩沉积区。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。
The Permian Yangxin Series in southern Sichuan consists of low permeabl tigt limestones, in which fractures, fissures and caves are developed, Natural gas may be found in some major fracture and nearby fissures and caves. However,whether a major fracture is confined is most significant for hydrocar- bon。enrichment and exploration, Three main indicator are herein: (1) coefficients of anomaly high forma- tion pressure; (2) types and salinity of formation water representative of the confined environment; (3) existences of multipays, multiple pressure systems and various water types along the section. The confined major fractures in Yangxin series are distinguished using the above indicators commbind with available longing, seismic and drilling data. It is suggested that except some areas where fractures are open and over- lying gypsum and/or salt laers have been denuded, a good many of the deep-buried fractures are well con- fined in the southern Sichuan. It is believed that natural gas will be found in these major fractures so long as drilled wells are carefully chosen and place in the favourable structures with hopeful hydrocahon poten- tial.
基金
"川南地区寻找天然气大储量裂缝圈闭研究"课题
关键词
断裂带
封闭性
二叠纪
断层
天然气
富集
Southern Sichuan
Early Permian
Fault zone
Confined fault
confined fracture
Judging indication
