Residual opening of hydraulic fractures created using the channel fracturing technique

The channel fracturing technique aims for discontinuous placement of proppant particles along the length of a hydraulic fracture in a way that a network of open channels or voids can be created between the proppant-filled regions of the fracture. In this paper, a simple theoretical model is developed to identify the optimal proppant volume fraction that maximises the effective conductivity of the partially-filled fracture while reducing the amount of proppant used. The fracture geometry is idealised as two-dimensional and a regular arrangement of proppant columns is considered. The residual opening profile of the fracture is determined as a function of the proppant column width and spacing, the mechanical properties of the rock and the proppant pack as well the magnitude of the compressive in-situ stress acting normal to the fracture plane. The effective fracture conductivity is then determined as a function of its residual opening profile. Some optimal estimates are provided for the conductivity enhancement and reduction in proppant use which can be useful for the application of the channel fracturing technique.