During waterflooding, or chemical EOR processes with polymers, fractures are frequently generated in injectors. This can have a profound impact on the process performance and reservoir management. A fracture growth model was developed and linked to a reservoir simulator that incorporates the effect of (i) particle plugging due to filtration of solids and oil droplets in the injected fluids; (ii) non-Newtonian polymer rheology (shear-thinning and -thickening) for polymer injection; (iii) thermal stresses induced by cold water injection; and (iv) stress and fracture reorientation due to poroelastic effect and rock displacements near fractures. Dynamic fracture growth due to particle plugging, thermal stresses, and complex polymer rheology during chemical flooding, affects the well injectivity and reservoir sweep significantly. With the fracture growth model, simulations can be made not only to make more accurate reservoir sweep and oil recovery predictions, but also to help identify well patterns that may improve reservoir performance.

It is shown that both injected particles and polymers play an important role in fracture propagation. Oil recovery and reservoir sweep during the injection of water or polymer into a homogeneous reservoir is relatively unaffected by the propagation of an injection induced fracture. However, in multi-layered reservoirs, reservoir sweep and oil recovery are impacted significantly by a combination of particulate plugging, polymer rheology, thermal stresses, and fracture growth. The results of a dynamically growing fracture obtained from our fracture growth model differ substantially from the oil recovery obtained for a static fracture. The shear rate dependence of the polymer rheology is critical in determining the injectivity, fracture growth, and oil recovery.