Numerical Modeling of Proppant Transport in Complex Hydraulic Fracture Propagation

Abstract Hydraulic fracturing is a stimulation technique used in unconventional reservoirs to generate sufficient reservoir contact for viable production. During stimulation, proppant is pumped into the system to keep fractures open when, at a later stage, injection ceases and fluid is recovered as fractures close. Thus, controlling proppant distribution in the fracture is important to improve well productivity. Several factors influence proppant placement and settling such as proppant size, proppant density and carrier-fluid rheology. However, accurately predicting, and consequently optimizing, proppant placement in complex fracture systems remains an industry challenge. The objective of this study is to use advanced modeling techniques of proppant transport inside complex fracture systems using a 3D simulator that couples geomechan ics, fracture mechanics, fluid behavior and proppant transport to assess the optimization of stimulation treatments. In this study proppant transport models incorporate the interaction between hydraulic fractures (HF) and natural fractures (NF) of various sizes and orientations. Treatments were simulated in systematic variations of proppant size, proppant density and fluid viscosity. Fluid rheology, proppant size and density are all major parameters affecting the proppant settling rate. In more complex systems, proppant placement is strongly influenced by the location, size, and orientation of natural fractures. Based on the size of proppant and viscosity of the injected fluid, proppant may or may not enter the natural fractures.