孤岛油田南区馆上段辫状河储层构型表征

孤岛油田南区馆5-6砂层组以辫状河沉积为主，主要发育的沉积微相有心滩、河道充填及溢岸砂。因河道频繁迁移摆动，砂体之间相互切叠，导致砂体内部构型复杂多变，严重制约了油田后续开发方案的调整和剩余油挖潜，迫切需要开展构型的精细解剖，深化对单砂体的叠置关系及分布规律的认识。采用储层构型分析方法将辫状河砂体划分为6个构型级次，重点对单一辫流带级次、心滩及其内部级次进行构型解剖。依据河道砂体在垂向上切叠模式的差异，对辫状河道进行垂向分期。利用河间沉积、河道顶部高程差、测井曲线形态差异，横向上对单一辫状河道进行侧向划界。在经验公式的约束下，利用测井响应特征、相对高程、剖面形态、落淤层产状的差异，准确识别心滩位置和形态。对单一辫流带和心滩相关数据进行统计和分析，提出了适用于稀井网条件下的单砂体识别经验公式。选取密井网井区典型的心滩进行实例解剖，分析不同类型心滩的沉积作用、厚度变化、发育位置和内部落淤层展布特征的差异，以期为不同类型心滩的判别和具有针对性的剩余油挖潜提供地质依据。

The characterization of braided river reservoir configuration in upper guantao formation of the south area of Gudao oilfield

The Ng5-6 sand formation in the southern district of Gudao Oilfield is dominated by braided river deposits, and the main sedimentary microfacies include channel bar, fluvial channel and overflow sand. Due to frequent channel migration and swing, sand bodies cut and overlap each other, resulting in complex and changeable internal architecture of sand bodies, which seriously restricts the adjustment of the subsequent development plan of the oilfield and the remaining oil exploration potential. It is urgent to carry out fine anatomy of the architecture and deepen the understanding of the superposition relationship and distribution law of single sand bodies. The braided river sand body is divided into six architecture orders by the method of reservoir architecture analysis, and the architecture anatomy of single braided stream band, channel bar and its internal order is emphasized. According to the difference of channel sand body cutting and stacking mode in vertical direction, the braided channel is divided into vertical stages. The single braided channel was delimited laterally by means of interchannel deposition, channel top elevation difference and log curve morphology difference. Under the constraint of the empirical formula, the location and shape of the channel bar can be accurately identified by using the difference of logging response characteristics, relative elevation, profile shape and occurrence of the falling-silt seams. Based on the statistics and analysis of the data of single braided stream band and channel bar, an empirical formula for single sand body identification is proposed under the condition of thin well pattern. The typical core bank in dense well pattern area was selected for example to analyze the differences in sedimentation, thickness variation, development position and distribution characteristics of falling-silt seams of different types of channel bar, in order to provide geological basis for the identification of different types of channel bar and targeted remaining oil exploration potential.