松辽盆地榆树林油田下白垩统泉头组扶余油层浅水三角洲沉积特征及其演化

松辽盆地榆树林油田下白垩统泉头组四段扶余油层沉积时期发育大型浅水三角洲沉积。本文基于12 口探井岩心与
2268 口钻井资料，通过单井岩心相分析、测井相分析、连井相对比和平面沉积微相研究，认为研究区发育浅水三角洲平原、
内前缘、外前缘和前三角洲亚相，以浅水三角洲平原亚相为主，平原分流河道和内前缘水下分流河道为主要沉积微相。在
扶三段（F Ⅲ）早期，研究区主要为浅水三角洲内前缘亚相，物源只来自北部 ；其后，三角洲向南进积，全区变为平原亚
相 ；F Ⅲ 3 小层沉积时期，南部物源进入，并与北部物源交汇，一直持续至扶一段（F Ⅰ）末期；在 F Ⅰ 3 小层沉积末期，湖
平面快速上升，南北两个三角洲退积，研究区中部依次出现浅水三角洲内前缘、外前缘和前三角洲。

Sedimentary Characteristics and Evolution of Shallow-water Delta of the Lower Cretaceous Fuyu Reservoir in the Yushulin Oil

The Yushulin Oilfield, located in the Sanzhao Depression of the Songliao Basin, developed large shallow-water deltas at
the time when the Fuyu Reservoir deposited within the Member 4 of the Lower Cretaceous Quantou Formation. Based on 12 well
cores and 2268 well loggings, by ways of single-well facies, logging facies, connecting-wells and plane sedimentary microfacies,
well-developed shallow deltas were recognized in the study area in which can be further subdivided into delta plain, internal front,
external front, predelta, and delta plain subfacies. Main sedimentary microfacies are plain distributary channel and internal front
subaqueous distributary channel. These two types of channelized sandstone bodies interlaced into a network. During the early
stage of the Member 3 of the Fuyu Reservoir, the studied area was dominated by shallow-water delta internal front subfacies which
was sourced from north only. Later, the delta prograded towards south, and the studied area changed into delta plain subfacies. At
the time of the third layer in the Member 3 of the Fuyu Reservoir, source from south appeared and intersected with the northern
source. This sedimentary condition continued to the latest stage of the first mewber of the Fuyu Reservoir FⅠ At the time of the
third layer of the Member 1, both the northern and southern deltas retrograded due to the sudden rise of lake level. In the middle
part of the studied area, delta internal front, external front, and predelta were developed in proper order.