Significant volumes of heavy oil are still present in fracturedrncarbonate reservoirs worldwide. Some of these reservoirs arerngood candidates for the application of thermally assisted gasoil-rngravity-drainage (TA-GOGD), a novel EOR technique.rnUnlike a normal steam flood, the steam is used as a heatingrnagent only to enhance the existing drive mechanisms. Thernelegance of TA-GOGD is that the fracture network is bothrnused for the distribution of steam (heat) and the recovery ofrnthe oil. The number of wells can therefore be kept to arnminimum compared to conventional steam floods. Followingrnencouraging pilot results in a field in Oman, a steam injectionrnproject is heading for implementation, a first of its kind on thisrnscale. Studies to date indicate that recovery factors of 25-50%rnwith Oil-Steam-Ratios of 0.2 – 0.4 m3/ton of steam arernfeasible. The success of the project is critically dependent onrnthe field-wide presence of conductive fractures and the abilityrnto characterize them. Both stochastic and deterministic studiesrnwere tried, but the latter method is now favoured as it allowsrnthe use of geological and dynamic understanding as input tornthe modelling and honours existing faults, deformationrnmechanism and the conceptual model. Fracturerncharacterisation is to some extent still an art and outputs arern“only static scenarios”. Therefore results should be validatedrnwith dynamic data as much as possible. The dynamic modelsrnare fully compositional, thermal and dual permeability, arncomplexity that is rarely encountered. Explicit fracture blockrnmodels are used to verify that the heating rate and GOGD arerncaptured properly, in particular for irregularly shaped fracturernpatterns. A new fully integrated workflow of fracturerncharacterisation with static and dynamic modelling will enablernto manage uncertainties and risks in a scenario basedrnapproach.
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