渤中凹陷东南斜坡带大型湖底扇沉积特征及勘探潜力

Sedimentary characteristics and exploration potential of large-scale sublacustrine fan in the southeast slope belt of Bozhong Sag

李俊伟 牛成民 官大勇 岳军培

LI Junwei NIU Chengmin GUAN Dayong YUE Junpei

中海石油(中国)有限公司天津分公司

Tianjin Branch of China National Offshore Oil Co., Ltd., Tianjin 300459, China

渤海海域渤南低凸起东南斜坡带在东二下段时期分布大面积的湖底扇，其展布面积及物源来源与渤海常规湖底扇的沉积特征截然不同。这种显著差异导致对其相带类型及划分存在些许争议，将其作为储集体存在一定风险。随着对渤海中深层砂体勘探程度的日益加深，确定其沉积体的沉积相类型及富砂性是首要任务，分析其成因机制更是研究的重点。该区无钻探井、且埋藏较深，因此，以层序地层学理论为指导，重建古地貌背景、古水深环境、结合源-渠-汇耦合理论及地震几何形态特征，确定物源属于期次性事件，分析其水下碎屑流搬运机制，明确了沉积体的发育部位、形成机制及沉积类型。最后应用多属性分析对研究区大型湖底扇内幕进行刻画，预测有利储层分布，对该区岩性油气藏勘探具有一定指导意义。

There is a large area of sublacustrine fan at the southeast slope of the Bonan low uplift in the Bohai Sea area in the Ed period.And its provenance origin and distribution area are quite different from the sedimentary characteristics of conventional sublacustrine fans in the Bohai Sea.Due to this significant difference, some disputes about the type and division of the facies belts are aroused, and whether it can be a reservoir is still an open question.As the exploration of the middle-deep sand bodies in the Bohai Sea is enhanced increasingly, the first task is to determine the sedimentary facies type and sand-rich property of its lithosomic bodies and the research focus is to analyze its genetic mechanism.Considering no exploration well is drilled in this area and its burial depth is larger, paleogeomorphologic setting and palaeobathymetric environment were reconstructed in this paper according to the theory of sequence stratigraphy.Then, based on source-channel-sink coupling theory and seismic geometry characteristics, the provenance was confirmed to be a periodical event.In addition, the transport mechanism of its subaqueous debris flow was analyzed, and the developmental site, formation mechanism and sedimentation type of lithosomic bodies were defined.Finally, by virtue of the multi-attribute analysis, the inside of the large-scale sublacustrine fan in the study area was characterized, and the distribution of favorable reservoirs was predicted.The research results can be used as the reference for the exploration of lithologic oil and gas reservoirs in this area.

10.13639/j.odpt.2018.S0.001