Quantitative characterization of reservoir quality differences in different levels of configuration units: a case study of typical fluvial sand bodies in Qinhuangdao 32-6 oilfield

      At present, research on the sedimentary configuration of river facies at sea focuses on the identification and characterization of different levels of interlayers, and there are the following problems: (1) the accuracy of predicting and characterizing the heterogeneity of physical properties within different levels of configuration units in river facies reservoirs is low, and there is a lack of methods and means; (2) The remaining oil distribution pattern controlled by the differences in physical properties of different levels of configuration units in the later stage of ultra-high water content is unclear. After more than 20 years of development, Qinhuangdao 32-6 Oilfield has entered the late stage of ultra-high water cut development, with a comprehensive water cut of 96.8%. After long-term high fold water flooding, the advantageous seepage channels have developed, and the continuous deep tapping of the main sand body faces great challenges.
      In response to the above issues, this article uses sedimentary genesis models as constraints to quantitatively characterize and characterize configuration units at different levels. Based on this, the influence of different levels of configuration units in river facies on the distribution of remaining oil is studied, forming a set of multi-level quantitative characterization methods for the internal structure of reservoirs in different levels of configuration units in river facies. The specific steps are: (1) Summarize the quality difference patterns of different levels of configuration units in river facies, as well as the geological knowledge base including lithofacies and configuration unit types, configuration unit structural styles and parameters, reservoir physical property parameters, etc. (2) Establish two-dimensional and three-dimensional prototype geological models of reservoir quality differences in configuration units, and carry out simulation of fluvial facies sedimentation. (3) Based on the prototype geological model, 3D seismic forward simulation is conducted to study the seismic response characteristics of reservoir configuration unit quality differences, and a feature map is established. The quantitative characterization of reservoir configurations based on different levels of configuration units not only enriches the research content of reservoir configurations, but also provides theoretical support for the characterization of heterogeneity in fluvial reservoirs.