The settling velocity of propping agents is a critical variable in the calculation of proppant distribution in a fracture. Most computer programs available in the industry today base estimates of settling velocity on a Stokes' Law type calculation. We have found that significant deviations from Stokes' Law settling velocities occur In cross-linked fluids and uncross- linked fluids (concentrations in excess of 0.48%).

This paper will discuss experimental results obtained with a dynamic system and the implications which these data have on prop transport calculations. In addition, correlations have been derived which can be used to predict the settling velocities of particles in cross-linked gels. A discussion of these correlations will be included.

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