陆相断陷盆地沉积可容空间变化与油气汇聚体系关系探讨

Discussions on the relations between sedimentary accommodation space change and oil-gas collective system in terrestrial fault-depressed basins

陆相断陷盆地的沉积可容空间变化规律控制着盆地的层序地层充填样式和生储盖发育规律,根据目前我国陆相断陷盆地的层序地层响应特征,将沉积可容空间的变化频率分为低频和高频两种类型。油气汇聚体系是陆相断陷盆地油气勘探的研究对象,根据油气聚集规模将其划分为大型、中型和小型等三种规模类型。具备不同层序地层充填样式的陆相断陷盆地一般发育不同规模类型的油气汇聚体系和相应的空间展布规律:低频率沉积可容空间变化的陆相断陷盆地可以发育大型、中型规模的油气汇聚体系;高频率沉积可容空间变化的陆相断陷盆地一般发育中型或者小型规模的油气汇聚体系,大型规模的油气汇聚体系欠发育。我国陆区陆相断陷盆地中的东营凹陷是低频率沉积可容空间变化的典型代表,东濮凹陷是高频率沉积可容变化的典型代表;海区陆相断陷盆地中的涠西南凹陷属于低频率可容空间变化的类型,海中凹陷属于较高频率可容空间变化的类型。

The rules of the sedimentary accommodation space changes in terrestrial fault-depressed basin control the sequence stratigraphic filling patterns and the development rules of generating-reservoir-cover assemblage.Based on the sequence stratigraphic response characteristics of the terrestrial fault-depressed basins in China,the change frequency of sedimentary accommodation space is divided into two types： lower frequency and higher frequency. Oil-gas collective systems are the main research objects in the oil-gas exploration of terrestrial fault-depressed basin.On the basis of the oil-gas accumulation scale,the oil-gas collective systems are divided into three types： great,middle and small ones.Commonly,the terrestrial fault-depressed basins with different sequence stratigraphic filling patterns develop different scale oil-gas collective systems with corresponding spatial distribution rules. Lower frequency sedimentary accommodation space change in terrestrial fault-depressed basins will develop oil-gas collective systems with great scale or middle scale while the higher frequency sedimentary accommodation space change will develop oil-gas collective systems with middle scale or small scale,the great scale oil-gas collective system developed rarely. In the continental China,Dongying depression is the typical representative of terrestrial fault-depressed basins with lower frequency sedimentary accommodation space change,and the Dongpu depression represents the higher frequency sedimentary accommodation space change.In the oceanographical area,the Weixinan depression belongs to the type of the lower frequency sedimentary accommodation space change,and the Haizhong depression belongs to the type of higher frequency sedimentary accommodation space change.