Study On Evaluation Of Horizontal Well Segmental Fracturing Yield

Horizontal well staged fracturing is the key engineering to the effective development of low permeability reservoirs.The production evaluation after fracturing is of great significance for predicting the effect of horizontal well staged fracturing and guiding the technology parameters design of horizontal well multi-stage fracturing.However,the existing productivity prediction models of multi-stage fractured horizontal well do not consider the influence of natural fractures,and seldom consider the seepage characteristics of different flow stages of horizontal well after fracturing for the closed boundary gas reservoir.Based on the sufficient investigation relevant literature about the productivity prediction of multi-stage fractured horizontal well at home and abroad,this paper carrys out the research of the productivity prediction of multi-stage fractured horizontal gas well with complex hydraulic fracture morphology which considering the influence of natural fractures for fractured gas reservoir.The main research contents are as follows:1.To study the seepage characteristics of three stages which are unstable seepage early, the late unstable seepage stage and pseudosteady seepage stage of multi-stage fractured horizontal well.2.Analyzing the artificial fracture morphology and the interference between hydraulic fractures,and a criterion about the interference between artificial fractures is proposed.3.Based on the complex potential theory,the potential superposition principle and the dual medium gas reservoir seepage theory,the productivity prediction models are deduced which considering the influence of natural fractures of multi-stage fractured horizontal gas well in unstable seepage early, the late unstable seepage stage and pseudosteady seepage stage.And the analytical solutions are obtained.4.A production simulation program of multi-stage fractured horizontal gas well is compiled,and the production simulation program is used for the calculation of a fractured horizontal well in the Sulige gas field.5.Calculating and analyzing the effect of reservoir parameters and hydraulic fracture parameters,such as gas reservoir thickness,bottom hole flowing pressure,matrix system porosity, natural fracture system permeability,artificial fracture number,artificial fracture length, artificial fracture width, artificial fracture permeability,artificial fracture azimuth,and artificial fracture spacing to the production of multi-stage fractured horizontal gas well.In this paper,a thorough research of the productivity prediction of multi-stage fractured horizontal well for fractured gas reservoir is carried out,and at the aspect of productivity prediction with complex hydraulic fracture morphology which considering the influence of natural fractures has certain innovation.This research work has great significance for dynamic analysis and fracturing parameters optimization design of fractured horizontal well.