--> Prototype Model of Modern Fluvial Deposits and Discussion on Architectural Units: A Case Study of Hailar River and Chaobai River

2018 AAPG International Conference and Exhibition

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Prototype Model of Modern Fluvial Deposits and Discussion on Architectural Units: A Case Study of Hailar River and Chaobai River

Abstract

Considering the great heterogeneity in fluvial reservoir of offshore oilfield, reservoir architecture characterization is the core for reservoir fine description. Based on previous study and under the research concept of historical comparison, the paper conducted GPR detection on modern sediments of meandering rivers, namely Hailar River and Chaobai River in China. This paper, through prototype model reconstruction, reviewed and explored fluvial architectural units features and concluded the following understandings. Firstly, due to the transformation of deposition dynamic mechanism and dominating factors, fluvial reservoir formation takes the 6th order interface as breaking point. As a whole, from lower order toward higher order, the sedimentation process of fluvial reservoir architecture tends to transfer from lateral to vertical, and the 6th and 7th orders are key interfaces. Secondly, under the influence of ancient valley landform, fluvial deposits present the characteristics of multi-stacked complex longitudinally, which is an indication of multi-stage valley terraces. Relatively continuous and stable sequence interfaces may be developed among different stages. Thirdly, individual point bars were mostly reserved in the form of remnant bodies. Generally, point bar complex, which is composed of several genetically related individual point bar remnants and takes abandoned channels as lateral boundary, may have favorable conditions to form isolated sedimentary units. Therefore, point bar complex is the most important unit for meandering river sand body architecture characterization of offshore oilfield development.