华北东部盆地叠合单元划分及其石油地质意义

Classifications of Basin Superimposing Units in Eastern North China and Analysis of Petroleum Geological Significances

华北东部是中国重要的能源基地,在地学界被认为属典型的叠合盆地,形成于前寒武纪结晶基底之上,经历了9个演化阶段,具有复杂的地质结构,体现了多期次、多种性质、多个延伸方向盆地的垂向叠加效应。文中将各期次单型盆地的静态格局分析与多期盆地的动态叠合研究有机地结合在一起,提出了叠合单元的概念,区划出继承型沉降(Ⅰ)、中沉新剥型(Ⅱ1)、中复新沉型(Ⅱ2)、中复新剥型(Ⅱ3)、中剥新沉型(Ⅱ4)和继承型隆剥(Ⅲ)等叠合单元类型。通过对各叠合单元石油地质条件分析,确定了Ⅱ2,Ⅱ4型叠合单元为以古生界为源的有利勘探区,Ⅰ,Ⅱ2型叠合单元为以中生界为源的有利勘探区,为准确分析和评价叠合盆地的石油地质条件提供了一种新的思路与方法。

The eastern part of North China is an important energy-resource region in China, and also a typical superimposed basin. On the crystalline Precambrian basement, it underwent nine evolutional phases. The eastern North China basin has complex geologic framework, typical of vertical superimposition with multi-phase, multi-property and multi-orientation character. On the basis of combination with the static framework of monotypic basin and the dynamic superimposition of multi-phase basin, the conception of basin superimposing units is brought forward. The eastern North China basin has six types of superimposing units, including inherited subsidence （Ⅰ）, subsidence in the Mesozoic and erosion in the Cenozoic （Ⅱ1）, sag or uplift in the Mesozoic and subsidence in the Cenozoic （Ⅱ2）, sag or uplift in the Mesozoic and erosion in the Cenozoic （Ⅱ3）, erosion in the Mesozoic and subsidence in the Cenozoic （Ⅱ4） and inherited erosion （Ⅲ）. Analysis of petroleum geological conditions of the basin superimposing units shows that Ⅱ2 and Ⅱ4 are the favorable exploration areas where the oil and gas came from the hydrocarbon source rocks of Palaeozoic; andⅠand Ⅱ2 are the favorable exploration areas where the oil and gas came from the hydrocarbon source rocks of Mesozoic. This paper provides a new idea of correct analysis and evaluation of the petroleum geological conditions of superimposed basins.