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.

摘要： 乌尔逊凹陷大磨拐河组下部(大二段至大三段)发育着近岸水下扇沉积、扇体由扇报、扇中和扇端组成,其沉积怍用类型为高密度至低密度浊流和碎屑流沉积,可进一步划分为七种不同内部结构的岩相类型.近岸水下扇储层经历了复杂的成岩历史,近源相主要受大气水埋藏成岩作用的影响,而远源相则主要受正常的埋藏成岩作用的影响.此外,片钠铝石的形成与深部岩浆活动有关,由于近岸水下扇不同的沉积类型具有不同的成岩历史和成岩机制,因而其孔隙类型和孔隙结构亦有明显差异.

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