珠江口盆地恩平凹陷韩江组钙质隔夹层特征和成因及油田开发意义OA

To solve the problem that the development of calcareous baffle interlayers constrains the fine-scale development of marine sandstone oilfields,core,well logging and resistivity boundary-detection inversion data were integrated.Using microscopic identification,facies analysis,mechanism investigation and distribution prediction,this study investigates the development characteristics,genetic mechanisms,distribution patterns and development significance of calcareous baffle inter-layers within the Hanjiang Formation reservoir of the F Oilfield in the Enping Sag,Pearl River Mouth Basin.Results show that calcareous baffle interlayers in the study area are mainly calcareous fine-and silt-sized sandstones,with calcite as the dominant calcareous component.Conventional logs are characterized by low gamma ray,high density,low neutron porosity,and high resistivity;the resistivity boundary-detection response presents a red high-resistivity feature.Combined with isotopic evidence,three genetic mechanisms are identified:dissolution-reprecipitation of bioclasts,evaporation,and sandstone-mudstone coupled diagenesis.The distribution of calcareous baffle interlayers is jointly controlled by"sequence-sedimentation-diagenesis".Vertically,calcareous baffle interlayers are continuously bedded near stable mudstone intervals,whereas those within sandstone reservoirs are discontinuously bedded and occur as massive patches.Laterally,calcareous baf-fle interlayers are more developed along the provenance direction.These results improve the accuracy of geological reserves estimation,guide the design and optimi-zation of development well types,and provide an important basis for reservoir heterogeneity characterization and fine residual-oil tapping under offshore sparse-well conditions.