[Society of Exploration Geophysicists, American Association of Petroleum Geologists, Society of Petroleum Engineers Unconventional Resources Technology Conference - Denver, Colorado, USA (12 August to 14 August)] Unconventional Resources Technology Conference, Denver, Colorado, 12-14 August 2013 - Evaluating the Effect of Natural Fractures on Production from Hydraulically Fractured Wells Using Discrete Fracture Network Models