Heterogeneous characterization of reservoirs at different levels and types of rivers---Taking the Neogene Reservoir of Qinhuangdao 32-6 Oilfield as an Example

The reservoir of Qinhuangdao 32-6 oilfield is a complex fluvial sedimentation, with large lateral variations in sand bodies, complex oil-water relationships, and diverse reservoir types. According to its sedimentary characteristics, the sedimentary facies of the oilfield can be further divided into two types: braided river and meandering river. The level of channel sand body configuration interface, configuration units, and their combinations are not yet clear; There is still a lack of understanding on how configuration units and their combinations under different levels of configuration interface control can control reservoir heterogeneity, which makes it difficult to predict the gas content inside individual sand bodies in the study area.

In response to the above issues, under the constraint of the configuration interface level, combined with the lithology and lithofacies of sedimentary microfacies units and their combination types, the configuration interface of the study area is divided. Based on the vertical sequence sedimentary characteristics of the configuration unit combination, the configuration unit combination is further divided, and the control effect of configuration on reservoir heterogeneity under different levels of interface control is clarified. Among them, the 5-level configuration interface controls the reservoir plane heterogeneity, which is controlled by the rise of the reference plane and structural subsidence; The level 4 configuration interface controls the heterogeneity between reservoir layers, which is controlled by terrain slope and erosion; The 3-level configuration interface controls the heterogeneity within the reservoir layer, which is controlled by hydrodynamic conditions, channel curvature, channel migration degree, sedimentary load, flow rate, and diagenesis. Finally, a control mode for reservoir heterogeneity under 3-5 level interface constraints was established.