Architecture Characterization of Shoreface Reservoir: A Case Study from the Donghe Sandstone Reservoir in the Hudson Oilfield

  The sandy shoreface reservoir exhibits a uniform lithology overall, with generally low overall heterogeneity. However, in the actual dynamics of reservoir development, the internal characteristics still reveal a complex oil-water relationship, indicating that the internal structure of the marine shoreface sand reservoir is intricate, and heterogeneity is pronounced. Therefore, it is imperative to conduct a quantitative characterization of the reservoir structure to provide theoretical and technical support for the interpretation of oil-water distribution and to further facilitate potential exploration.

  To solve the above problems, this paper, guided by the sedimentary genetic model, systematically quantified and characterized the architectural interfaces and architectural units in hierarchical order. On this basis, the influence of configuration interfaces and configurational units on the distribution of remaining oil was investigated, forming a set of multi-level architecture methods for quantitatively characterizing the internal structure of shoreface reservoirs. The specific steps are as follows: (1) After establishing that the third-order and fourth-order architectural elements primarily influence the oil-water distribution interface within the closely spaced well pattern area, the third-order and fourth-order architectural interfaces of the reservoir are quantitatively identified. This identification is based on the sedimentary genetic model and is integrated with data from both vertical and horizontal wells. A quantitative relationship is then established between the maximum thickness and maximum extension length of the third-order and fourth-order architectural interfaces in both parallel and vertical paleo-shoreline directions. The distribution characteristics of these interfaces, along with the progradation and regression evolution traits of the third-order architectural interfaces along the vertical paleo-shoreline, are precisely defined. (2) Building upon the identification of architectural interfaces, the focus is placed on the classification, recognition, and distribution studies of third-order and fourth-order architectural units. The distribution characteristics of different-order architectures are delineated in detail, and a developmental model for third-order architectural units is established. Finally, the reservoir architecture characterization results are validated using production dynamic data, confirming that the method accurately characterizes the internal structure of sandy shoreface facies reservoirs and quantitatively depicts their internal heterogeneity. The quantitative characterization of the marine shoreface sand reservoir architecture not only enriches the research content on reservoir architecture but also provides theoretical support for the characterization of heterogeneity in marine facies reservoirs.