A conceptual model is presented for flowback of hydrofracturing fluid in an elastic fracture of plane or radial geometry with rigid walls. The fluid follows the power-law or Ellis constitutive equation. The aperture and pressure fields are derived under the lubrication approximation for different boundary conditions and the two rheologies. Late-time scalings for the aperture confirm and extend earlier literature findings. Model results are verified experimentally with an ad hoc device obtaining a good match between theory and experiments.