苏丹Muglad盆地凯康凹陷西斜坡早白垩世沉积层序及其控制因素研究

Study of Sedimentary Sequence of the Early Cretaceous of the Western Trend of Kaikang Depression of Sudan and Its Controlling Factors

苏丹Muglad盆地是重要的油气探区,受区域构造的影响,早白垩世沉积储层发育演化与构造演化密切相关。在盆内地震、测井及岩心资料综合分析的基础上,重点对4区西斜坡早白垩世的沉积层序特征及其控制因素进行了研究。结果表明:Muglad盆地经历了3次裂谷断陷活动及其后裂谷期的3次热沉降坳陷活动,形成了6个二级层序;在二级层序格架内将白垩系Abu Gabra组至古近系Adok组划分13个三级层序;早白垩世断陷期主要发育湖泊及辫状河三角洲沉积体系,坳陷期主要发育辫状河及三角洲沉积体系;断陷-坳陷的构造演化和同沉积断裂对不同期层序的沉积体系发育具有明显的控制作用。

Muglad Basin of Sudan is an important hydrocarbon accumulation zones,and influenced by the re-gional structure,the Early Cretaceous sedimentary reservoir developed evolution is closely related with tectonic evolution.On a basis of the comprehensive study of the seismic,well logging and core data,the characteristics of sedimentary sequence of the Early Cretaceous of the western trend of block 4 in Muglad Basin and its control-ling factors are studied.The main results and achievement are as follows：（1 ）The basin has experienced three large rift movements and three thermal subsidence depression movements of post-rift stage,and formed 6 se-condary-order sequences.In those secondary-order sequence stratigraphic frameworks, the target formations from Cretaceous Abu Gabra to Paleogene Adok are divided into 13 third-order sequences;（2）Lacustrine and braided delta sedimentary systems mainly developed at rift stages,and braided river and delta sedimentary sys-tems mainly developed at sag stages;（3 ）The study shows that the sedimentary systems development of different sequence are mainly controlled by the synsedimentary fault and tectonic evolution of rift and sag stages.