A Method About Analyzing The Production Data Of Multiple-fractured Horizontal Wells In Tight Gas Reservoirs

During the production of tight sandstone gas reservoirs,due to the tightness of sandstone reservoirs,the permeability of the reservoir is poor.Therefore,multiplefractured horizontal wells are used to develop tight sandstone gas reservoirs to obtain high oil or gas production.Because of the features of tight gas reservoirs,a series of problem such as low production,rapid production decline,low final recovery rate and low singlewell reserve may occur.Firstly,the mathematical models of flow in the formation and fractures were established.Using coupling equations,the analytical solution of vertical fractured well in early period can be obtained.Because there is no interference between fractures in early period,the early production of multiple-fractured horizontal wells can be obtained via superposition principle.Secondly,considering the interference of fractures,the non-uniform distribution of fractures and conductivity difference,using superposition principle the pseudo-steady production solution of multiple-fractured horizontal wells in bounded reservoirs can be acquired under constant pressure production.The main influencing factors of the pseudosteady production of each facture are dimensionless conductivity and drainage area.Thirdly,by introducing equivalent well radius and wellbore flow skin model,a new method of transient production analysis for multiple-fractured horizontal wells with infinite conductivity is established according to superposition principle.Analysis shows that there is interference between fractures,so under the case of same length and uniform distribution the outmost fracture has the highest production but the facture in the middle is relatively small.With the increase of the number of fracture,the total production of horizontal well increases but the increasing speed of total production and the production of each fracture decrease gradually.Therefore,the optional fracture number can be obtained combining with economic assessment.At last,to validate the correctness of results in this paper,they are compared with results from Eclipse(a kind of numerical simulation software)and RTA(a kind of production data analysis software).In addition,the results in this paper are applied to dynamic analysis of production and prediction for steady production years.