Fine studies of sedimentary microfacies on lower series of Bi-304 area in Zhaowa oilfield

Reservoirs of Bi-304 area in Zhaowa oilfield belong to underwater fan deposit of proximal and fast slumping accumulation,with big fan body thickness and fast transverse lithologic changes,and this can lead to poor physical properties and oil-bearing characteristic,strong heterogeneity and non obvious traditional logging electrical characteristics.As the glutinite bodies are generally of multiphase development and through multiple sedimentary formations,the internal geological structure and oil/water relationship are very complex,and therefore there is great difficulty in reservoirs distribution.By using traditional methods of sedimentary facies,the studies on single sand body features and fine sedimentary microfacies have been carried out.In combination with the dynamic production data and porosity-permeability chart,the revision on single sand microfacies figures has been made.Based on this,the fine description of the plane distribution of different sand bodies under the same period,as well as the description of the connecting relation and heterogeneity has been conducted and therefore,the plane figures of the oil-bearing layers have been made.After field application,many production problems such as unclear direction of water injection,non-obvious oil wells effect,high water cut in some wells and low recovery degree have been solved,which lays a solid geological foundation for well pattern adjustment and achieve the purpose of good oil wells effect and enhanced oil recovery rate and production rate.