【摘要】 “深盆气”是一个既不能反映天然气成藏机理也不具有分类地质意义的非正式术语。如果按照其特点及地质模式,要确定一个气藏是否属于“深盆气”,首先就必须找到“气水倒置”的界面,而该界面的确定往往不易落实。“根缘气”被界定为致密储层中的具有“根状”天然气聚集,通常表现为致密储气层与气源岩的大面积接触,尤其是致密储层底部具有含气特点,天然气运移聚集服从“活塞式”原理。“根状”特点的出现表明了浮力的限制性作用,与常规气藏依靠浮力驱动的置换运聚模式形成原理上的差异。由于储层孔隙结构的复杂性,气体运移方式在2种典型的气藏类型之间常出现一系列过渡,它们也属于“根缘气”的范畴。因此,采用“根缘气”概念进行气藏类型判识,避免了对区域性气水倒置界面的追索。对于典型的根缘气藏,往往可以达到“单井定乾坤”的效果。更多还原

【Abstract】 Deep basin gas, or basin-centered gas, is a term used all through a special history period. It is neither a conception from mechanism, nor does it reflect the signification of classification for gas accumulations. According to characteristics and geological model of deep basin gas, gas accumulations can not be made certain as deep basin gas until the boundary of gas over water is making sure. However, the feature cannot be confirmed earlier and easier for the lack of well information and some other reasons. Source-contacting gas was defined as the rooted gas accumulating in tight sands that contact directly with the source rocks of natural gas. Usually, gas was accumulated at the bottom but not the top of the tight sands, which indicates that the buoyancy of gas was limited and gas was migrated in piston-typed manner. Meanwhile, conventional trapped gas shows replacement style for migration by buoyancy. Because of the structural complexity of reservoirs, the accumulation of natural gas always shows transitional models. A series of transitional types appear between the accumulations of typically conventional trapped gas and source-contacting one. Making sure the types of gas accumulations by using the conception of source-contacting gas can not only avoid the confirming of regional distribution for converted gas and water interface, but also get the first-rate effect in the exploration. Generally, it can be made certain whether the gas show belongs to source-contacting gas by only a single well.更多还原