Case study of sandbody architecture and quantitative parameters of the far-source sandy braided river: Saertu Oilfield, Daqing, China

Abstract

Aimed at the braided river sandbodies deposited in the pure oil area of western Saertu Oilfield in the Songliao Basin, Daqing, Placanticle, the sedimentary physical simulation experiments were designed. The characteristics of channel bar microfacies were identified and analyzed by four rounds of experiments. Based on the measurement results, the correlation parameter model of the braided river reservoir architecture was established by describing the geometric occurrence of the structures of the single-phase braided river sandbodies and channel bar. Combined with prototype sedimentation simulation experiment, the internal quantitative architecture of far-source sandy braided river was researched by identifying and analyzing the interface of individual well. The interfaces of the 5th-order, 4th-order and 3rd-order architectures were emphatically analyzed and the inter-well quantitative architecture model was established. The research results showed that the interlayer in the center of channel bar was approximately horizontal, with dip angle of about 1°. In short-axis toward end direction, the dip angle of the architecture interface of accretionary body was 2–4°. Combined with the internal dip angle and occurrence of channel bar sandbodies, the interface of the accretionary body in the central part of channel bar was parallel, with dip angle of no more than 2°. The dip angle of the accretionary body in water flow direction was large, which was 2°–5°. On this basis, the size of braided river, channel bar and accretionary body was calculated quantitatively in the target area, and different orders of braided river sandstone reservoirs were described.