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Abstract:
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Polymer -free viscoelastic surfactant -based (VES ) fluid systems have been used to eliminate polymer -based damage and to efficiently transport proppants into the fracture . Current models and correlations neglect the important influence of fracture walls and fluid elasticity on proppant settling . This report presents an experimental study that investigates the impact of fluid elasticity and fracture width on proppant settling in VES fluid systems . Proppant settling experiments are performed in shear -thinning VES fluids . Experimental data is presented to show that fluid elasticity plays an important role in controlling the settling rate of the proppants . It is shown that elastic effects can increase as well as reduce the settling velocities depending upon the rheological properties of the fluid and properties of the proppants . Data is presented to show that the settling velocity reduces significantly as the proppant size becomes comparable to the fracture width . The reduction in settling velocity due to the presence of the fracture walls depends on the rheological properties of the fluid , ratio of particle diameter to fracture width as well as the diameter of the particle . |