Method And Application Of Shale Gas Production Prediction Considering Heterogeneous Of Fracturing Zones

The improvement of the staged fracturing technology of horizontal wells has led to the commercial development of shale gas,which has become a prerequisite for the efficient production of shale gas.However,due to the influence of the process,the fracturing process will aggravate the heterogeneity of the reservoir,and then affect the production capacity.In addition,mass transfer mechanisms such as slippage,diffusion,and desorption of shale gas are also important factors that must be considered when making capacity prediction.Since most of the existing shale gas productivity models do not take into account the impact of heterogeneity in the reformed area,it is very meaningful to establish a production capacity prediction method that takes into account the heterogeneity of the reformed area.Firstly,the non-linear factors affecting shale gas flow including gas viscosity,compressibility factor,and apparent permeability are characterized.The heterogeneity of the reformed area caused by the fracturing process and the stress sensitivity of the reservoir are characterized.Its effect on gas flow is analyzed.Secondly,based on the principle of material balance,a mathematical model of gas flow including multiple mass transfer mechanisms is established,and the effects of gas physical parameters,reservoir heterogeneity and stress sensitivity are comprehensively considered.On this basis,a shale gas well productivity model considering heterogeneity is established.The numerical solution of the model is obtained through programming and the existing productivity model is used for comparison and verification.The consistency is good and the model is proved to be accurate.Then,the influence of nonlinear factors and fracture parameters on the model results is analyzed.The results show that the initial production capacity is mainly affected by the main fracture permeability and the main fracture half length,and the cumulative production capacity is mainly affected by the degree of heterogeneity,the main fracture half length,the permeability coefficient of variation and Langmuir volume.Finally,the application analysis of the production capacity model is carried out based on the examples of the mine,and the production characteristics of the model and the utilization rules of the transformation area are analyzed.Based on the consideration of heterogeneity in the fracturing zone,comprehensively considering the influence of multiple gas mass transfer mechanisms and nonlinear factors,the shale gas fracture horizontal well productivity prediction method is established,and the numerical solution of the model is obtained.The results of productivity prediction are more accurate,which has certain guiding significance for the actual production analysis of shale gas fractured horizontal wells.