桑托斯盆地盐下裂谷系构造特征及圈闭发育模式

桑托斯盆地是近10年来全球油气勘探的热点地区之一,其深水盐下多个大型、特大型油气田的发现令业界关注。为了揭示盐下裂谷系圈闭目标的分布规律,指导盐下油气勘探,以油区构造解析理论为指导,在区域构造演化特征分析与地震资料解释的基础上,结合三维数据的应用分析及已发现的油气圈闭特征,明确了盆地盐下裂谷系圈闭目标的分布规律。盐下圈闭目标主要分布在构造高的地垒发育区,与背型盐丘共生;同时,在局部区域,圈闭目标受具有走滑性质的继承性活动基底断层控制,沿断裂带状断续分布,且主要分布在断层内部弯曲段或断裂带的叠覆区。这种圈闭发育模式的建立,能够很好地克服盐岩屏蔽作用对盐下勘探目标识别带来的障碍,提高对盐下油气藏分布规律的认识,从而降低钻探风险。

Structural characteristics and trap development patterns of pre-salt rift system in Santos Basin

Santos Basin is a hot spot in the global oil and gas exploration in recent ten years,and the discovery of many large and extra large oil and gas fields in deep water is concerned by the industry.In order to reveal the distribution pattern of target trap in pre-salt rift system for exploration,under the guidance of the oilfield structural analysis theory,the regional tectonic evolution analysis,interpretation of seismic data,3D data analysis,and the characteristics of the oil and gas traps,the distribution patterns of trap targets in pre-salt rift system are confirmed as follow:pre-salt trap targets mainly distribute in the horst area of high structure,covered by salt dome;meanwhile in some areas,the traps controlled by inherited basement faults with strike slip characteristics are of discontinuous distribution along the fault belt,mainly distribute in the internal bending section or overlap zone.The establishment of the trap development model can overcome the obstacles caused by the shielding effect of salt rock on the pre-salt target identification,improve the understanding of the pre-salt hydrocarbon accumulation distribution pattern,and reduce the drilling risk.