Research on the Effect of Uneven Proppant Settlement on Well Productivity in Stimulated Reservoir

Abstract

The characteristics of proppant tarnsportation, settlement and distribution in fractures are of great significance to the effectiveness of complex fractures, as well to investigate the shale reservoir stimulation volume and productivity evaluation. This paper studies the effect of the uneven distribution of proppant sand banks on well productivity. A numerical model that comprehensively considers adsorption, desorption and stress sensitivity, and characterizes different settlement degree of proppant sand banks is established. The pressure distribution and productivity characteristics of fractured reservoir considering proppant non-uniform distribution are studied, by comparative analysis of different sand bank shapes, main fracture conductivity, reservoir matrix permeability and other sensitivity parameters. Meanwhile, the main controlling factor that affects the productivity of horizontal wells after the formation of sand banks are obtained. The results show that the proppant settlement greatly reduces the productivity. The effect of fracture conductivity on well production could ignore when the fracture conductivity is more than 4 μm2·cm in specific fractured reservoir. It is recommended to use small particle size proppant (100 mesh) to propped natural fractures or induce fractures. The higher the matrix permeability, the greater the impact of proppant settlement on well productivity. Beisdes, the measurement to prevent proppant settlement should be taken in high permeability zones. Considering the influence of proppant uneven settlement in complex fractures is of great significance for evaluating well productivity and guiding on-site fracturing operations.