Study On Productivity Prediction Of Fractured Horizontal Well In Tight Oil Reservoirs

As one of the unconventional oil and gas resources,tight oil is widely distributed and has great potential for development.Because permeability is low and connectivity is poor in tight oil reservoirs,it is difficult to obtain economic production by conventional recovery methods.At present,horizontal well fracturing technology is used to develop tight oil reservoirs.However,when horizontal wells are fractured,the productivity prediction of wells is complicated because of different fracture parameters and mutual interference between fractures.The accuracy of productivity prediction of tight oil fractured horizontal well not only has impact on optimizing fracturing design,but also has impact on evaluating the efficiency of the fracturing treatment.Therefore,it is of great significance to study the productivity prediction of tight oil fractured horizontal well.The main content is as follows:At first,combining the seepage process and characteristics of tight oil in the fracture,and applying complex potential theory and the principle of potential superposition,the productivity prediction model of fractured horizontal well is established,which considers the starting pressure gradient and the interference of multiple fractures.The factors affecting the productivity of the fractured horizontal well in tight reservoir are studied by using the productivity prediction model,which including the starting pressure gradient,the number of fractures,the length of fractures,the fracture permeability and the fracture spacing.Secondly,the model of the fractured horizontal well on tight oil reservoirs is established by using the reservoir numerical simulation software,and the factors affecting the productivity of the fractured horizontal well are also analyzed.Through the single factor analysis,it is found that the horizontal well productivity will increase with the increase of the number of fractures,the length of fractures,the permeability of fractures and the spacing of fractures,and the extent of increase will decrease.These results are similar to the results obtained from the productivity prediction model of fractured horizontal well.Finally,factors affecting the productivity of the fractured horizontal well are analyzed by orthogonal experiment.The influence factors including geological factors and engineering factors.And the important ranking of these factors is reservoir thickness,reservoir permeability,the number of fractures,porosity,fracture permeability,fracture length,horizontal well length.