Single Well Productivity And Single Well Controlled Reserves Evaluation Of Shale Gas Horizontal Wells In Weiyuan Block

As a natural gas resource,which can be mined from shale,it is compared with conventional natural gas there are many complex characteristics of shale gas formation and enrichment,for example,the mechanism of shale gas accumulation has complex and multiple mechanism,the permeability of shale gas reservoir is low,the flow resistance is larger than that of conventional gas,shale gas flow itself exists diffusion,desorption and many other complex forms.All these have put forward more requirements for the establishment,selection and application of single well productivity and single well control reserve evaluation method for shale gas horizontal well.Based on the systematic study of the geological characteristics of Weiyuan block and the characteristics of the target gas reservoir’s tectonic position,high quality shale thickness,organic carbon content and formation pressure coefficient,the paper establishes a stable seepage model of the shale-gas reservoir matrix-pressure fracture coupling fracturing horizontal well,The factors affecting the productivity of fractured horizontal wells are analyzed in the light of mutual interference in the discharge areas formed by multiple transverse cracks,the paper establishes a shale gas correction formula(IGLG)based on Genliang Guo fracturing horizontal well productivity formula and a steady-state productivity prediction formula of shale pressure-fractured horizontal well based on the type-capsule seepage model(EFR),a productivity evaluation method based on the common constraint of the IPR curve and the wellhead IPR curve is established,and the productivity evaluation method based on two-item dynamic coefficient inversion is established,and the calculation program of each method of productivity evaluation is compiled and the application of the example of Weiyuan block is compared.Using the material balance method to evaluate the single well controlled reserves of shale pressure-fractured horizontal well,using the Arps descending model and evaluating the single well controlled reserves of shale pressure-fractured horizontal well,establishing the intersection method combining the harmonic descending method with the material balance law,and creating the program and the operating interface,In this paper,single well controlled reserves of shale pressure-fractured horizontal wells are evaluated and compared with different single well controlled reserves evaluation methods.The results show that Weiyuan structure is a large dome structure,as the relative tectonic gentle zone and good preservation condition,the high quality shale thickness tends to be thickened from west to east.With the increase of the number of artificial fractures in the shale gas horizontal wells,the gas production increases gradually,but due to the interference between the joints,As the number of cracks increases to a certain extent,the increase in gas production decreases gradually.The results of IGLG and EFR productivity formulas show that with the increase of the formation permeability,the difference between the two increases gradually,and the result of the Langmuir pressure increase is also increasing.The calculated value of IGLG is significantly larger than that of EFR;the method of productivity evaluation based on the common constraints of the IPR curve and the wellhead IPR curve avoids the linear correlation of the traditional two-item deliverability equation indicating curve is not high or even the slope is negative.Productivity evaluation method based on two-item dynamic coefficient inversion of formation pressure the ability to evaluate single well productivity in the absence of capacity test data,both of which are guided by multi-objective optimization,require less computational results and more accurate and reliable;The relationship curves of p/Z and Gp computed and plotted on the basis of the productivity evaluation method of two-item dynamic coefficient inversion of formation pressure can reflect the special mining characteristics of shale gas reservoirs,the material balance equation of the constant volume gas reservoir is equally applicable to the single well controlled reserve evaluation of the shale gas horizontal well in Weiyuan block as Arps production decline method.Innovation Method,the intersection method combines the advantages of the material balance method and the harmonic descending method,and the procedure interface design is reasonable and the evaluation result is more accurate and reliable.Innovative shale gas horizontal well single well productivity and single well controlled reserve evaluation method is helpful to carry out production dynamic analysis scientifically and efficiently,which can provide important technical support for shale gas reservoir economic development in Weiyuan block.