晚侏罗世裂谷运动对北海盆地油气富集的控制作用

为了探讨北海盆地油气富集的控制因素,对前人在该区的大量研究成果进行了整理和分析,结果显示,北海盆地三叉裂谷所在的3个地堑具有上下2层不同的结构特征,即晚侏罗世末期的裂谷拉伸运动造就了北海盆地的下构造层,而早白垩世之后的热沉降作用塑造了北海盆地的上构造层;断层主要分布在下白垩统之下的老地层中。北海盆地油气成藏组合主要受下构造层的控制,成藏模式主要表现为中生代砂岩断—背斜油气藏,因此,可以认为,北海盆地油气富集的主要控制因素是晚侏罗世—早白垩世的裂谷拉伸运动。

LATE JURASSIC-EARLY CRETACEOUS RIFTING IN NORTH SEA AND ITS CONTROL ON HYDROCARBON ACCUMULATION

Controlling factors on hydrocarbon accumulation in the North Sea Basin were studied in this paper based on previous research data. It reveals that there is a double-layer structure in the trifurcate rift grabens. The lower layer is a faulting structure formed by the movement of stretch rifting by the end of Late Jurassic, while the upper is a depressed structure formed by the thermal subsidence after Early Cretaceous. Most of the main faults occurs in the strata older than Cretaceous. The plays of hydrocarbon accumulation are Mesozoic fault-anticline sandstone controlled by the lower rift structure. Therefore, the rift stretching during Late Jurassic-Early Cretaceous is the main controlling factor to hydrocarbon accumulation.