Integrated simulation of multi-stage hydraulic fracturing in unconventional reservoirs

By using the UFrac model, we investigate several key problems in hydraulic fracturing such as fracture height growth, perforation spacing optimization, and thermal effect on proppant placement. Important conclusions are drawn from the simulation results. The strength of stress interaction is found to be related to the fracture geometries. Stress shadow effect does not only affect the flow partitioning and fracture size distribution, but also influence the proppant transport. Friction loss in the wellbore can affect the decisions on spacing optimization. Moving inner fractures closer to the heel of the wells would be beneficial for fracture propagation balancing. Fluid viscosity loss due to heating from the surrounding formations results in longer but narrower fractures and faster settling of proppant. The modeling of proppant distribution aids in better characterization of the fracture conductivity, thus provides more reliable prediction of the well productivity.