Study On Transient IPR And Test Production Method For Fractured Horizontal Wells In Tight Gas Reservoirs

Producing Of unconventional resources has achieved great success with horizontal well technology and multi-stage fracturing technology.The current unconventional reservoir productivity evaluation cannot characterize the seepage mechanism of low permeability reservoirs and the unstable stage of low permeability reservoirs.Therefore,it is of great significance to study the productivity of multi-stage fracturing horizontal wells in dense reservoirs and apply them to on-site testing production.In this paper,by studying the flow mechanism of tight reservoir and fracturing horizontal well flow method,based on the five-region percolation model,the seven-zone model with fracture been un-penetrated longitudinal reservoirs is considered and the sensitivity of reservoir parameters and fluid properties is considered.And there is an analytical model of the threshold pressure gradient,and the relationship of the dimensionless pseudo pressure with time under the condition of constant production is calculated and verified by mathematical calculation.Then,the factors affecting the transient IPR were studied by numerical simulation.The transient IPRs under constant pressure production and constant production were calculated respectively with and without production history.Finally,the above model was used to derive the production under constant pressure production conditions.The relationship of change,combined with the transient IPR study,calculates the transient IPR of the analytical solution.At the same time,comparison of transient IPRs of analytical and numerical models,even more;it analyzes the IPR taking into account the stress-sensitive of parameters and the threshold pressure gradient.Finally,through investigation of testing production methods,it was found that the existing capacity test cannot be directly applied to low-permeability tight reservoirs.Therefore,the full consideration of the production characteristics in low-permeability reservoirs—unstable flow dominates,and the principle of production superposition is applied to improve the existing modified isochronous well testing method,through theoretical derivation,proposes a production test method applied to dense and low-permeability reservoirs.Then,through an example calculation,it is found that this method can more accurately rate gas well productivity and develop a production system for development.Provide more accurate basis.