断-盖空间配置类型及其对油气成藏的控制作用

SPATIAL MATCH TYPES BETWEEN THE FAULT AND CAPROCK AND THEIR CONTROLS ON THE HYDROCARBON ACCUMULATION

为了研究含油气盆地断裂发育区油气分布规律,通过研究断裂对盖层破坏程度及其对下伏油气封闭能力,剖析了断-盖空间配置类型及其对油气运移和聚集的控制作用。断-盖空间配置分为不封闭型和封闭型,其中不封闭型包括盖层完全被断裂错开和盖层断接厚度小于其封油气所需的最小断接厚度的2种断-盖配置类型,封闭型是指盖层断接厚度大于其封油气所需最小断接厚度的断-盖配置类型。断-盖空间配置对油气运移的控制作用主要表现为:封闭型断-盖配置对油气垂向运移起变径作用,对油气侧向运移起连接作用;不封闭型断-盖空间配置对油气垂向运移起减慢作用和部分变径作用,对油气侧向运移起变径作用。断-盖空间配置对油气聚集的控制作用主要表现为:封闭型断-盖空间配置油气均在其下聚集分布;不封闭型断-盖空间配置油气可在其上下聚集分布。

In order to study the oil-gas distribution law in the well-developed zone of hydrocarbon-bearing basin, by means of the caprock destructed degree by the faults and their underlying petroleum sealing abilities, the spatial match types between the fault and caprock and moreover their controlling actions on the oil-gas migration and accu- mulation are analyzed. The match types can be divided into 2 kinds-closed and non-closed. In detail, the latter can be further classified into 2 forms that the caprocks are completely destroyed by the faults and fault connected thick- nesses of the caprocks are less than the minimal thickness of the sealed petroleum; the former thicknesses are more than the above minimal thickness. The controlling actions of the matches on the migration are displayed as follows ： in light of the former, the pathway changing roles are played for the vertical migration, and moreover the connecting roles are presented for the lateral migration; for the latter, the slowing and partial pathway changing roles are dis- played for the vertical migration, and pathway changing actions are discovered for the lateral migration. The princi- pal performances for the controlling action of the matches on the petroleum accumulation are presented as follows： for the former, the hydrocarbon is accumulated below, while the latter, the petroleum is enriched below and above.