陆相页岩气储层裂缝支撑剂铺置规律研究.

In order to study the proppant migration law of fractures in continental shale gas reservoirs, a visual fracture simulation system was used to carry out proppant migration and settlement experiments, which simulated the process of proppants migration and settlement under the conditions of different fracturing fluid viscosities, displacements, sand ratios, proppant particle sizes and proppant densities. At the same time, the PIV particle velocimetry technology was used to draw the velocity fields at the entrance and the front edge of the sand bank, aiming to further analyze the particles movement characteristics during the migration process. And the following research results were obtained. The migration process of proppants in artificial fractures is divided into four stages: the early stage, the middle-early stage, the middle-late stage and the equilibrium state. At the entrance of the fracture: the velocity of suspended particles is approximately horizontal, and the velocity of particles on the surface of the sand bank is upward along the slope. The propulsion of proppants mainly depends on the carrying effect of liquid viscous force; As the displacement increases, there will be obvious disturbances in the flow field. When the displacement is greater, the degree of disturbance is stronger. At the front edge of the sand bank: There is an obvious vortex phenomenon in the flow field at the top of the slope; The viscosity of the liquid increases, the strength of the vortex is weakened, and the viscous force increases. Under the impact and carrying effect of the liquid, the particles lay farther away; As the displacement increases, a larger vortex appears in the entire front edge area, and the vortex action becomes stronger. At this time, the impact of the liquid makes the proppants placement better; When the sand ratio increases, the number of vortices increases, the strength of vortices intensifies, the spread range enlarges, and the proppants migrate to the farther end of the fracture. When the proppants particle size in slippery water is smaller and the density is higher, the sand bank becomes more uniform, but to achieve the required effect, the sand-carrying liquid is needed. [ABSTRACT FROM AUTHOR]