Study On Fracture Identification Method Of Chang 4+5 Reservoir In Nanliang West District

Nanliang Oilfield is an important oil-producing area in the Ordos Basin.The Chang 4+5of the Yanchang Formation is one of its main oil-bearing intervals.In recent years,due to the influence of micro-fracture development,strong reservoir heterogeneity and other factors,the water breakthrough in the corner well is fast and the water cut rises quickly in the development process.Therefore,it is of great significance to analyze the reservoir heterogeneity,reservoir development status and micro-fracture development characteristics,which provides a reliable basis for the development and production of the reservoir.By sorting out and analyzing the geological data,oil test data,well logging data,production data and dynamic monitoring data of the research area,this paper studies the geological characteristics and development status of the research area,analyzes the reservoir heterogeneity and reservoir sand body connectivity based on the geological characteristics of the research area,summarizes reservoir development rules;to accurately identify and correct the fractures by means of water absorption profile,tracer monitoring and production dynamics,to summarize the distribution law of fractures,to analyze the influence of fractures on the distribution of remaining oil,and to infill and adjust the well pattern in the fracture zone.According to the comprehensive analysis,the reservoir in the research area is ultra-low permeability reservoir,and the reservoir has strong vertical and plane heterogeneity.The reservoir is faced with the development contradiction of low productivity of single well,fast initial decline,uneven water cut.The comprehensive identification method of low-permeability reservoir fractures based on dynamic data was used to identify 62 fractures,and such fractures were further corrected one by one.Finally,a total of 49 fractures were implemented.The fractures are mainly distributed in the small layers of Chang 4+5₁² and Chang 4+5₁³.The main direction is near east and west.45 new wells were infilled and deployed with full consideration of the current situation of the reservoir and the distribution of fractures.