关键词: 海拉尔盆地, 大磨拐河组, 水下扇, 储集层特征, 沉积岩相, 成岩作用, 沉积类型, 岩石成分, 孔隙结构, 孔隙类型

Abstract: Nearshore subaqueous fans develop in the lower Damoguaihe formation,consisting of innerfan,midfan,and outerfan association.Seven lithofacies and layer divisions have been identified and interpreted as to be high-and low-density terbidites and debrites.Nearshore Subaqueous fans have under gone a complicated diagenetic history.The diagenesis of Proximal fans is affected by meteoric burial,but the distal,faeies is mainly controlled by normal burial.The formation of dawsonites is a diagenetic event,relating to deep magmatic movement.Difference in the microfacies of nearshore subaqueous fans exhibits difference in pore types and pore geometries due to their diagenetic histories and mechanisms.