Abstract: The reservoir architecture is the key factor influencing the outcome of oil and gas production, and controls the distribution of the remaining oil. Based on the theory of architectural-element of fluvial reservoir and the depositional model of braided rivers, this study performed hierarchical analysis and dissected the reservoir architecture elements of sandbodies in detail for the purpose of future production. Structural elements including braided channels, channel bars, abandoned channels, and mud drapes, were identified and confirmed. Contact modes among architectural elements of different levels and periods were recognized to complete the detailed characterization of the reservoir architecture of braided channel. Based on these results, and in conjunction with interpretation of water-flooded layers from logging data of different time periods and dynamic production performance, water-flooding characteristics at various production and adjustment stages were reconstructed. The water-flooding process controlled by reservoir architecture of braided channel was dynamically characterized. The distribution of the remaining oil controlled by the reservoir architecture is summarized and confirmed by the detailed water-flooding results of densely spaced sealed coring wells. The results show that the braided river reservoir has a generally high water content, with three-dimensional inhomogeneous and random water-flooding characteristics that do not occur in segmentations. The non-flooded regions are very scattered. Locations with local deterioration of reservoir physical properties, mud drapes, and low-permeability barrier occlusion directly control the distribution of the remaining oil.

Key words: braided channel, reservoir architecture, water-flooding characteristics, remaining oil, Daqing Oilfield