Numerical simulation of hydraulic fracture propagation in weakly consolidated sandstone reservoirs

Abstract

Frac-packing technology has been introduced to improve the development effect of weakly consolidated sandstone. It has double effects on increasing production and sand control. However, determining operation parameters of frac-packing is the key factor due to the particularity of weakly consolidated sandstone. In order to study the mechanisms of hydraulic fracture propagation and reveal the effect of fracturing parameters on fracture morphology in weakly consolidated sandstone, finite element numerical model of fluid-solid coupling is established to carry out numerical simulation to analyze influences of mechanical characteristics, formation permeability, fracturing fluid injection rate and viscosity on fracture propagation. The result shows that lower elastic modulus is favorable for inducing short and wide fractures and controls the fracture length while Poisson ratio has almost no effect. Large injection rate and high viscosity of fracturing fluid are advantageous to fracture initiation and propagation. Suitable fractures are produced when the injection rate is approximate to 3–4 m3/min and fluid viscosity is over 100 mPa·s. The leak-off of fracturing fluid to formation is rising with the increase of formation permeability, which is adverse to fracture propagation. The work provides theoretical reference to determine the construction parameters for the frac-packing design in weakly consolidated reservoirs.