Abstract:

 It is of great significance for the efficient development of sandy braided river reservoirs to clarify the different characteristics and genesis of the same level architecture elements. Based on modern deposit, field outcrop, and core, the quantitative architecture characterization was carried out in typical layers by taking the sandy braided river of lower He8 Member in Sulige gasfield as the study subject. Architecture differences were emphatically compared from the fifth to third level in typical layers of H8x2-2, H8x1-3, and H8x1-1. Influenced by source condition and base level change, the braided belt scale of lower He8 Member changes from 650.0 m to 1 750.0 m. The single braided belt has three different distribution patterns: Isolated type, lateral splicing type, and vertical superposition type. Architecture differences in individual sandbody are remarkably affected by flooding, channel erosion, and chute scour. The scale of braided river bar is greater with an average thickness of 7.2 m in the layer of advantage lithofacies probability higher than 80%. The average length and width are 1 402.0 m and 809.0 m in H8x2-2. The architecture differences of the third level are minor in braided bar. Falling-silt layers have the similar feature of thin, gentle and lenticular distribution. They are 0.1-0.4 m thick and with a dip angle of 1-3 degrees. Single lateral accretions are 360.0-565.0 m wide. The number of lateral accretions and the single size control the difference in the average bar scale in every layer. With the constraint of architecture differences in different levels, a three-dimensional geological model is built up to accurately reflect the distribution of sandy braided river architecture in Sulige gasfield, which can provide a reference for later development adjustment of the reservoir.

Key words: architecture differences')">

architecture differences, braided river bar, sandy braided river, Lower He8 Member,
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