Research On The Law Of Proppant Settlement And Migration In Complex Fracture

Different from the fracture networks formed by the fracturing of shale reservoirs,the fractures formed by the hydraulic fracturing of the tight sandstone reservoirs are complex,consisting of main fractures,open and staggered natural fractures.Clarifying the law and mechanism of proppant settlement and migration in the main seam and branch seam is of great significance for guiding the design of tight sandstone fracturing.In this paper,based on the theory of solid-liquid two-phase flow,combining with numerical simulation and experimental data,the mechanism and rule of proppant settlement and migration in complex fractures are studied systematically.Firstly,the characterization parameters of propoant are determined.Based on the equilibrium height and the leading edge parameters,the two-dimensional area of the sand and the growth-free area ratio of two parameters were introduced to fully describe the sand volume distribution and the growth rate of change in the fractures.Preferred numerical calculation method and use experimental data to verify the simulation results.The effects of fracture parameters,pump injection parameters,proppant properties,and inter-fracture interference on the distribution pattern of propoant bank in the main seam and branch seam were studied by numerical simulation.The influences of angle,branch seam position,branch seam width,fluid velocity,injection location and proppant density on the height of the embankment,leading edge parameters,two-dimensional area and non-dimensional area growth ratio are quantitatively characterized.According to the velocity field and the distribution of flow lines in the fractures,the main mechanism and control fractures of the proppant transport process was studied.The distribution characteristics of the proppant in the double-branch mode,the volume distribution of the sand bank under the influence of the flow rate,and the proppant transport mechanism in the fractures were analyzed.