Research On Productivity Of Multiply Fractured Horizontal Wells For Low Permeability Reservoirs

With the development of low permeability reservoir in China,the research on the productivity of the segregated fracturing horizontal well has become an indispensable part of the fracturing stimulation effect.A large number of actual drilling data has been accumulated during the application of this technology in the field of low permeability reservoir.How the actual drilling data is fully applied to capacity study and optimized fracturing design is important to improve the precision of productivity prediction and fracture parameters optimization.The productivity study of segregated fracturing horizontal well mainly consists of analytic method and numerical simulation method.Analytic method is mainly used for simple prediction and evaluation of fractured horizontal well productivity to solve the problem of single phase flow;numerical simulation can solve the problem of three-phase flow of oil,gas and water,which has a irreplaceable advantages for production capacity simulation of fracturing horizontal wells,but it is difficult to accurately describe fracturing parameters.This paper studies production capacity of segregated fracturing horizontal well from two aspects.The first one is to combine the fracturing design software and productivity prediction model to predict the fracturing productivity of segregated fracturing horizontal well.First,this paper designs segregated fracturing by fracturing data software,and simulates hydraulic fracturing parameters;then,the paper puts simulated parameters into productivity prediction model to do numerical simulation or numerical difference for calculation production capacity of fractured horizontal wells.After calculation,this paper puts the calculated data into equations predicted by field fracturing parameters and fractured productivity to find out the fracturing parameter value corresponded with the parameter value of designed parameters,restricting the designed values,so as to improve the rationality of fracturing design and the accuracy of productivity prediction;Second,fracture the layer according to the optimized fracturing design.Detect the downhole microseismic in the construction process.Analyze the parameters of fractured and simulated in order to optimize the designed parameters.According to the production and test curve,analyze actual single well production of different periods of time and forecast daily production of single well to further improve the productivity prediction accuracy in production test.Finally,realize the continuous optimization of the segregated fractured horizontal well to make the fractured production forecast more accurate.In the course of the study,starting from the geological factors affecting the fracturing and engineering factors,combining with the characteristics of horizontal well fracturing technology and production mechanism,through the analysis of production test of developed horizontal wells and the impact of fracture geometry,conductivity,crack location,crack spacing,angle and matrix permeability,it shows that production increased with the increase of the number of fractures,fracture length and fracture conductivity;and the larger the angle between fracture and horizontal wellbore is,the higher the production is;for different fracture layouts,cracks at the same position should be staggered,and spacing between the root and the end of the crack is less than that of internal crack;the crack spacing can be increased to reduce the interference between different cracks;The production of different position is different,and the production of the middle fracture is low.