| Sulige gas field is a typical tight sandstone gas reservoir with the geological characteristics of quick lateral change of sand body and strong reservoir heterogeneity.Fracturing horizontal Wells have been applied to gas field development on a large scale.From the perspective of development characteristics and effects,affected by the "one-point method"of gas test to seek high open-flow potential of production by 50%,the horizontal Wells’production allocation is unreasonable,resulting in rapid decline in output and pressure and great difficulty in stable production.However,there are some disadvantages such as long time,high test cost,and impact on gas well production.Therefore,how to quickly and effectively evaluate the productivity of fracturing horizontal Wells,guide the reasonable production allocation of gas Wells,and improve the development effect of "three low" gas reservoirs is a major problem faced by gas field development.Starting from the productivity evaluation method,this project investigated the current research status of the percolation theory of tight gas reservoirs.Based on the analytical model of fracturing horizontal Wells in multiple stages of tight sandstone gas reservoirs,the productivity equation of fracturing horizontal Wells was established by using the method of simulated and modified isochronal well test based on fitting production dynamic data and parameters obtained from dynamic monitoring.Analyze the influence of main control factors on the productivity of fracturing horizontal Wells,evaluate the initial reasonable output of different types of Wells,and determine the reasonable development system of fracturing horizontal Wells in sulige gas field.Affected by the geological characteristics of sulige gas field,the open-flow potential of gas test with "one-point method" is used for production allocation,and then the initial level of fracturing horizontal Wells is 50%higher,which is not conducive to the effective development of gas field.The open flow potential of fracturing horizontal Wells evaluated by the numerical well testing method is within 10%of that by the productivity test,indicating that this method is applicable to the productivity evaluation of fracturing horizontal Wells in sulige gas field.The average absolute open flow potential of 45 fracturing horizontal Wells is 26.5×104m3/d.The influence of main control factors on fracturing horizontal well productivity is analyzed.Considering non-darcy effect,the evaluation method for the gas recovery curve of fracturing horizontal well I,II,III reasonable initial production respectively open flow potential of 1/5,1/4,2/7.Aiming at three years in a stable,consider stress sensitivity of reservoir numerical simulation method to evaluate Ⅰ,Ⅱ,Ⅲ well reasonable initial production were 6.5×104 m3/d3 3.5×104 m3/d,2.2×104 m3/d. |
