Flow Model And Productivity Prediction Methods Of Typical Carbonate Gas Reservoir

AY gas field is a typical carbonate gas reservoir,and it has many differences with the conventional reservoirs.It is composed of matrix and fracture system.Fracture system of high permeability is the main seepage channel of fluid,and matrix system of high pore and low permeability is the main reservoir space of the gas.Also,the mechanisms of pore structure and gas-water two-phase flow are different with regular gas reservoirs and seepage rule is more complicated.The stress sensitivity characteristic and non-Darcy flow are obvious.Also,there is a certain degree of edge and bottom water in this gas reservoir,which shows the two-phase flow characteristics.Therefore,it is necessary to consider the influences of these factors and establish a percolation model and productivity prediction method suitable for typical carbonate gas reservoirs.Based on the analysis of dynamic characteristics,this paper establishes a flow model of typical carbonate gas reservoir considering the effects of stress sensitivity and nonDarcy flow simultaneously.And modern mathematic methods and material balance method are used to solve the model.Then this paper establishes the dual medium gas reservoir productivity prediction method,and draws the theory template curve.The effects of stress sensitivity and non-Darcy flow on the productivity of typical carbonate gas reservoir are analyzed by using the established sample curve chart.Combined with the field application analysis of the instance wells in the target block,the production law of the instance wells is analyzed,the reservoir parameters are speculated by the established model,the productivity dynamic prediction of the instance wells is carried out,and the production dynamic prediction method suitable for the target block is established.The research results of this paper have guiding significance for understanding the percolation characteristics and dynamic characteristics of typical carbonate gas reservoirs and improving the exploitation effect of carbonate gas reservoirs.