Study On The Well Pattern Optimization Of Low Permeability Reservoirs In Wuliyasitai Oilfield

Wuliyasitai oilfield is characterized with low porosity and ultra-low permeability,so that hydraulic fracturing technique is needed to ensure sound development.Since the oilfield went into operation,many problems greatly hinder its effective development,such as improper well pattern,high production decline rate and ineffective water injection,etc.Therefore,it is critical to study on the well pattern optimization.This paper firstly performed a thorough literature review about the current research on the development of low permeability reservoir and well pattern optimization.Next,the mathematical model considering threshold pressure and hydraulic fracturing is established for well performance prediction.Numerical simulation model is set up,whose accuracy is examined by history match.On this basis,optimization of well pattern types has been made integrated with reservoir engineering methods.Then,reasonable well spacing considering hydraulic fractures is calculated on the foundation of point sources and sinks theory.Economic reasonable and limited well spacing are also derived to give a reasonable range for well spacing.Besides,the effect of formation anisotropy has been analyzed to optimize the reasonable ratio of well spacing and row distance,on the basis of which the optimal well spacing and row distance have been calculated.Besides,fracture parameter optimization has been conducted aiming to finalize the best fracturing treatment.Lastly,the production and injection parameters have been optimized,including the bottomhole pressure of production well and that of the injection well.The conclusions of this research could provide some insights for the effective development of Wuliyasitai low permeability reservoir.