Study On Factors Affecting Productivity Of Fractured Horizontal Wells And Fracture Parameters Optimization

Due to features of tight oil reservoirs including low porosity,low permeability and poor continuousness,it is difficult to obtain good results with conventional stimulation measures.Volume fractured horizontal wells can effectively reduce seepage resistance and improve development effect,it has become the key to increase production in tight reservoirs.The fractured well performance is affected by a variety of factors,it is of great significance for the development of tight reservoirs to determine the key factors and optimize parameters.In this paper,multistage fracturing horizontal well productivity prediction model and mathematical statistics method are used to analyze the factors affecting production;then,fracability logging interpretation model that combines brittleness index,fracture toughness,and ground stress is established.The effect of fracability and physical property parameters is comprehensively considered by “AND” relationship and threshold factors.Only when the fracability and physical property parameters at the same position in the horizontal well section are greater than their respective threshold factors,the location can be regarded as the ideal perforation position.On this basis,in order to save computational cost and time cost effectively,the radial basis function surrogate model is established for the first time and used to optimize the fracture parameters with particle swarm algorithm.Then the volume fracture network model is used to optimize the construction parameters based on the fracture information;finally a set of volume fracturing optimization design methods for tight reservoirs is formed.The study shows that: fracturing stages,segment spacing,half fracture length,and fracture conductivity are the main parameters affecting the fractured well performance;the effect of construction parameters on volume fractured horizontal well production: fracturing fluid volume> pumping rate> sand volume;The threshold factor can be adjusted according to the needs of mine,so as to obtain the ideal fracturing position;The use of radial basis function surrogate model and particle swarm optimization algorithm to optimize the fracture parameters can effectively save computing resources,reduce the optimization cycle with small search step and wide search space.The optimized effect is achieved.The research results can provide theoretical guidance and technical support for the optimization of volume fracturing in tight reservoirs.