Study Of Fracture Modeling In Ultra-low Permeability Reservoir With Multi-scale Fracture

Low permeability reservoir,extra low permeability and ultra-low permeability account for a large proportion of reserves in our country.In the process of developing this kind of oil and gas reservoir,as the development of the micro millimeter-scale natural fracture and the meter-scale induce hydraulic fracture,and the dynamic change of fractures in the course of waterflood development,the multi-scale complex fracture system is formed,besides,low permeability reservoir has poor physical properties,high heterogeneity and complex structure usually,consequently the water tends to form a channeling way along the fracture in the course of waterflood development,leading to the low efficiency of water injection,low sweep efficiency of water,and poor development of reservoir.So how to use static and dynamic data to identify fractures and their distribution in the reservoir,how to characterize the reservoir parameters and distribution of fractures,and how to characterize the dynamic characteristics and the impact of fractures in the course of reservoir development are urgent research problems today.This paper which basing on static data,dynamic data and test analysis data of oil field,setting about the causes of reservoir tectonic fracture development,combining with the method of statistics,the rupture law of rock,and the fractures distribution analysis in wells,and simulating the tectonic stress by the method of finite element,forecast the natural fracture in the reservoir quantitatively with comprehensive analysis both in static and dynamic way,and base on it,modeling the DFN model of this area and doing the study of fracture reservoir simulation.By means of discrete fracture modeling method and reservoir dynamic analysis,the calibrated small-scale natural fracture model is created;combining with the fracturing data,the large-scale model is established by the method of deterministic modeling,and merge with the natural fracture model to form a dual medium model.Choosing a typical group of wells and considering the mechanism of seepage mechanism of multi-scale fractured medium and matrix,we used the dual media model which characterizes the multi-scale fractures to simulated and evaluated the parameters of reservoir,which improve the accuracy and reliability of simulation and solve the problems of water breakthrough in ultra-low permeability fractured reservoir;According to the corresponding formula,the fracture opening pressure and reservoir fracture pressure of this field are calculated.The study provides a basis for the development plan and adjust measures,at the same time,it also improve the production and the recovery rate of ultra-low permeability oilfield with complex fractured,and make the development of extra low permeability reservoir more economical and efficient,which have an important significance to the reservoir development.