Relative role of accommodation zones in controlling stratal architectural variability and facies distribution: Insights from the Fushan Depression, South China Sea
Relative role of accommodation zones in controlling stratal architectural variability and facies distribution: Insights from the Fushan Depression, South China Sea
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适应带在控制地层结构变异和相分布中的相对作用：来自南海浮山凹陷的见解
DOI：
10.1016/j.marpetgeo.2015.08.027
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发表时间：
2015
影响因子：
4.2
通讯作者：
Cunyin Xia
中科院分区：
文献类型：
--
作者：
Entao Liu;Hua Wang;Yuan Li;Nicole D. Leonard;Yuexing Feng;Songqi Pan;Cunyin Xia
在沉积盆地中，深入认识调节/转换带对地层结构和相带分布的控制作用，可以提高油气藏定位的成功率。福山凹陷是位于南海北部湾盆地东南部的一个箕状断陷亚盆地。通过对地震反射、古地貌、断裂活动性及沉积相展布的对比分析，认为盆地内斜坡发育三种不同类型的斜坡沿着福山凹陷南斜坡发育多层次的斜坡带（西部为多级断阶斜坡带，调节带为坡折带，东部为缓坡带），以及位于东西断裂系统交汇处的大规模调节带。进一步分析表明，调节带不仅对南坡的地层结构变化起着重要的控制作用，而且对调节带地区的沉积相分布也起着重要的控制作用。高水位期沉积体系的沉积主要受沉积物供给和北西向转换断层的控制。主要水系沿沉积物供给方向沿着通过调节带进入福山凹陷，沉积水流路径平行于调节带轴线，沉积水流被限制在NW向转换断层的邻近区域。低水位期，转换断层对沉积相的控制作用不大，湖底扇沉积物偏离调节带，沿沿着向向下运移，斜向调节带轴线。低水位阶段的水流划分受流型和地形的影响较大。同时，调节带地区表现出不同于东西部地区的独特油气成藏模式，表明福山凹陷今后的油气勘探应分层次进行。
In sedimentary basins, a better understanding of the controlling effect of accommodation/transfer zones on stratal architecture and facies distribution can improve the success rate of locating hydrocarbon reservoirs. The Fushan Depression is a half-graben rift sub-basin located in the southeast of the Beibuwan Basin, South China Sea. In this study, comparative analysis of seismic reflection, palaeogeomorphology, fault activity and depositional facies distribution indicates that three different types of inner-basin slopes (i.e. multi-level step-fault slope in the western area, slope flexure zone in the accommodation zone area and gentle slope in the eastern area) were developed along the southern slope of the Fushan Depression, together with a large-scale accommodation zone located at the intersection of the western and eastern fault systems. Further analysis shows that the accommodation zone played an important role in controlling not only stratal architectural variability in the southern slope but also depositional facies distribution in the accommodation zone area. During the high-stand stage, the deposition of depositional systems was mainly controlled by sediment supply and the NW-trending transfer faults. Major drainage systems entered the Fushan Depression through the accommodation zone along the direction of sediment supply, and sedimentary flow paths were parallel to the accommodation zone axis with sedimentary flows constrained to the adjacent areas of the NW-trending transfer faults. By contrast, during the low-stand stage, the transfer faults had little control over depositional facies distribution, and the sublacustrine fan sediments diverted away from the accommodation zone and flew down along the northeast, oblique to the accommodation zone axis. The flow division in the lowstand stage might be greatly influenced by flow type and topography. In addition, the accommodation zone area demonstrated unique hydrocarbon accumulation models different from the western and eastern areas, suggesting that the future exploration should be conducted at different levels in the Fushan Depression.