Abstract:

The study of proppant transport in fractures is of great significance for guiding fracturing design and evaluation. The current researches of proppant placement rules mainly focus on displacement, proppant type, fracturing fluid viscosity, etc. However, there are few studies on the effects of different proppant combinations on proppant transport rules. In this paper, the experimental schemes of the influence of different proppant combinations on proppant transport rules are designed. Then the self-designed visual parallel plate device is used to carry out these experiments. The results show that the distribution of the proppant with smaller particle size is more evenly in the fractures, but the proppant with larger particle size is easier to settle at the wellhead. When medium particle size and large particle size proppant are combined in different proportions, there are small differences in the equilibrium heights of the formed sand bank, but the differences between the non-uniformity of the sand bank height are large. Meanwhile, a large amount of proppant settles at the entrance end of the crack. The proppant filling amount in the deep crack is small, and the effective filling crack with sufficient length and diversion capacity is failure to be formed. When the medium and small particle sizes are combined in different proportions, the proppant can obtain a farther distance than that of the combination of medium particle size and large particle size. The height of the formed sandbank is ideal, and the difference in the non-uniformity of the height of the sand bank between different proportions is also greater.

Key words: hydraulic fracturing, proppant, transport rule, particle size combination, visual simulation