Experimental Investigation of Proppant Flow and Transport Dynamics Through Fracture Intersections

TL;DR

This study experimentally examines how fracture intersection angles, fluid viscosity, flow rates, and proppant concentration influence proppant transport in hydraulic fractures, revealing that intersection angles significantly affect flow dynamics and proppant settlement.

Contribution

It provides new insights into the effects of fracture intersection angles on proppant transport, a previously underexplored aspect in fracture flow studies.

Findings

Proppant transport is highly sensitive to fluid viscosity and flow rates.

Fracture intersection angle significantly influences proppant velocity and settlement.

Proppant volumetric concentration has limited impact compared to other factors.

Abstract

This paper investigates proppant flow and transport in intersected fractures at angles typical for intersections of pre-existing and new hydraulic fractures. Proppant is small granular material, which is placed into hydraulic fractures during geothermal and hydrocarbon reservoir stimulation and props the fluid paths open during reservoir exploitation. This study uses plexiglas laboratory slot experiments enhanced with an advanced image analysis for identifying particle trajectories and quantifying slurry velocities. Although proppant flow and transport has been broadly studied, the effects of intersecting fracture angles have not, especially coupled with fluid viscosities, flow rates, and proppant volumetric concentration effects. This paper specifically investigates the role of intermediate fracture angles, which have been identified to occur most frequently when the new hydraulic fractures intercept the existing ones. Results show that proppant flow and transport behavior after the intersection is very sensitive to carrying fluid viscosity and flow rates alteration, while differentiating proppant volumetric concentrations have a limited effect. Fracture intersection angle itself has a clear effect on proppant flow velocities and proppant settlement; furthermore, it enhances the effects from fluid viscosity, fluid flow rates, and proppant volumetric concentrations.