Modeling of pressure dissolution, proppant embedment, and the impact on long-term conductivity of propped fractures

The production performance of fracturing wells depends greatly upon hydraulic fracture conductivity. A novel long-term propped fracture conductivity model is presented that considers the effects of diagenesis incorporated pressure dissolution processes at grain-to-grain contact interfaces, dissolved mass transfer processes that are controlled by diffusion on the edges of particles and precipitation processes at free surfaces, as well as upon elastic compressed deformation, arrangement, and the embedment of grains. Studies using the model have shown that propped fracture conductivity will decrease gradually with the influence of proppant crushing, formation fines migration, fracturing fluid damage, scale precipitation, and proppant dissolution and rearrangement under reservoir conditions. The simulation results were consistent with experimentally obtained data and presented a reasonable explanation for observed phenomena in the field. Therefore, it is considered that this novel model can predict conveniently and accurately the varying relationships of long-term propped fracture conductivity under complicated formation conditions.