The flow characteristics of fractures are significantly affectedrnby the stresses acting upon them. Reservoirs where thernmajority of the fluid flow is through fractures are veryrnsensitive to the stress regime and its perturbations. Activities,rnsuch as production from a reservoir or injection into arnreservoir, cause changes in the fluid pressure. This will alterrnthe effective stress, which in turn will affect the flow ofrnhydrocarbons through the fracture network. In order tornunderstand how hydrocarbons flow within a fracturedrnreservoir it is necessary to determine the influence of bothrnstress and fluid pressure in a fracture network.rnThere have been many experimental studies showing therninfluence of stress on the flow of fluid through single fracturesrnfrom which a relationship between fracture permeability andrneffective stress can be developed. Effective stress acting on arnfracture can be established by considering the orientation ofrnthe fracture relative to the in-situ stress regime and the fluidrnpressure within the fracture. Once the effective stress acting onrna fracture has been found the corresponding permeability canrnbe assigned within a discrete fracture network (DFN) model.rnThis approach then allows examination of stress-sensitive flowrnwithin fractured reservoirs.rnThis paper presents a methodology for incorporating insiturnstresses and stress changes due to production and injectionrnin DFN modelling. The approach is significantly differentrnfrom published methodologies on this subject, which are basedrnon continuum porous medium modelling. By simulating andrninterpreting well tests in the fracture network during reservoirrnappraisal and after significant production, the presentedrnapproach would help in determining the influence of stress onrnhydrocarbon flow within a fracture network and to optimisernfuture well locations and orientations.
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