Three-dimensional facies architecture analysis using sequence stratigraphy and seismic sedimentology: Example from the Paleogene Dongying Formation in the BZ3-1 block of the Bozhong Sag, Bohai Bay Basin, China

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• 作者：Hongtao Zhu ; Xianghua Yang ; Xinhuai Zhou ; Keyu Liu
• 关键词：Seismic sedimentology ; Incised valley ; Delta ; Dispersal pattern ; Dongying sequences
• 刊名：Marine and Petroleum Geology
• 出版年：March, 2014
• 年：2014
• 卷：51
• 期：Complete
• 页码：20-33
• 全文大小：9218 K

文摘

The Bohai Bay Basin is a classic non-marine rift basin in eastern China. The Paleogene Dongying sequences are the main hydrocarbon-bearing stratigraphic unit in the basin. Using three-dimensional (3-D) seismic data and one well control in the BZ3-1 Block in the western slope of the Bozhong Sag, we analyzed 3-D facies architectures of the Dongying sequences. The Dongying Formation, a second-order sequence, can be subdivided into four third-order sequences (from base to top: SQ1, SQ2, SQ3, and SQ4). The facies architecture was analyzed by using the seismic sedimentology approach based on 3-D seismic data. Sediment of the Dongying sequences was derived from the northern Shijiutuo Uplift via four major configurations of incised valleys, namely 鈥淰鈥? 鈥淯鈥? 鈥淲鈥? and composite shaped incised valleys. Seismic stratal slices reveal branching and converging characteristics of the channels from upstream to downstream. On the basis of an integrated analysis of well log, core data, seismic facies based on multi-seismic attributes, three sedimentary facies (e.g., 鈥渄elta鈥? 鈥渇an-delta鈥? and 鈥渟hore鈥?or 鈥渟hallow lacustrine鈥?facies) have been recognized. The four types of incised valleys and their evolution control the sedimentary systems in the sedimentation area. The numbers and sizes of the fans are controlled by the sedimentary systems at various scales. Incised valley-fill and deltaic sand bodies are excellent hydrocarbon reservoirs and potentially good exploration targets for the study area. The reservoir quality of sequences SQ1, SQ2, and SQ3 become better gradually from base to top. The proposed sediment dispersal patterns may aid in the prediction of potential reservoir distribution. This study also demonstrates that facies architecture analysis using sequence stratigraphy and seismic sedimentology may serve as an effective approach for constructing 3D facies models for petroleum exploration in areas lacking of well or outcrop data.