Study On Production Prediction Methods Of Vertical Wells In Low Permeability Reservoirs

The ratio of low permeability reservoir in the production is becoming larger and larger recently.Factors influencing the capacity of low permeability oil reservoirs of numerous and complicated,so the correct analysis and evaluation of these factors are becoming more and mere important.According to the reservoir geologic parameters,the parameters of well pattern and fracture parameters on well productivity prediction,accurate prediction of the well productivity can be made,which can ensure good production capacity and economic benefits and has great significance for low permeability oilfield development.According to numerical simulation methods and mineral statistics,heterogeneous reservoir properties,residual oil saturation,threshold pressure gradient and development factors are integrated in the paper.Considering the production o f vertical wells,the appropriate well pattern can be chosen,then the well pattern is devided into several regions according to the shunt line and the main streamline,later on the parameter calculation method can be got according to the well point parameters,reservoir heterogeneity and source direction.For fracturing vertical wells,two cases are analysed,including infinite and finite conductivity flow partition.For infinite conductivity fractured vertical wells flow partition,the well pattern is divided into regions according to the equipotential lines and the sparsity of streamlines;For finite conductivity fractured vertical wells flow partition,the effect of vertical fractured wells is transformed into vertical wells with equivalent well radius,then the corresponding production calculation is got using the flow-tube method.Using calculations of Matlab and case analysis,the validity of the prediction method is verified.The results showed that the capacity formula is deduced for low permeability reservoir vertical well productivity prediction,it is significant for oil exploration.The productivity formula can be applied to low permeability reservoir production prediction such as two-phase flow,heterogeneity and multiplayer production.