CANADA BACKGROUND: Thermal oil recovery prediction can be done using Numerical simulation Unscaled laboratory models Scaled laboratory models These techniques have advantages and disadvantages depending on the objectives; we shall talk about the value of physical models as compared to numerical simulation. THERMAL PROCESSES OF INTEREST LIMITATIONS OF PHYSICAL MODELS Steam injection Unscaled physical models are useful for Steamflooding gaining insight into process mechanisms, as a first Cyclic steam stimulation step towards the development of numerical models, Without formation fracturing but out of scale With formation fracturing Scaled models are useful for modelling only a In situ combustion portion of the field, with limited geological SAGD: Steam-Assisted Gravity Drainage description Electrical heating VALUE OF SCALED MODELS NUMERICAL SIMULATION Scaled models retain many aspects of reservoir Numerical simulation is a powerful flow and fluid interactions that are not represented technique, but is still limited in describing all the in numerical simulation mechanisms in a thermal process. Some areas of Scaled models have been successfully used for uncertainty: all thermal processes 1. Relative permeabilities (temp., hysteresis) Scaled models are a valuable adjunct to 2. Emulsion formation and flow numerical simulation 3. Geochemical aspects, hydrothermal reactions 4. Proper representation of flow in a horizontal STEAM INJECTION MODELS well Low pressure scaling criteria of Stegemeier et 5. Geomechanical aspects al. have been very successful, and modified by the authors for a variety of applications, including ADVANTAGES OF NUMERICAL horizontal wells used by the authors to study field SIMULATION projects Numerical simulation permits detailed treatment of High pressure models were used for steam a reservoir, using a grid which demands much flow around injection and production wells, vertical more information than is really available and horizontal Simulation can account for geological features, if known Multiple wells can be simulated for interaction and communication 159 NUMERICAL SIMULATION vs. PHYSICAL MODELS Figure 1 steamflood model TWO EXAMPLES OF SAGD MODEL TYPES OF EXPERIMENTS STUDIES Many different experiments were conducted: Steam distribution in SAGD wells Some examples: · Steam is very unevenly distributed around the · Bottom water studies injection well difficult to predict using a · Effect of gas/solvent injection simulator · Water injection after steam · The final recovery curve for SAGD from the · Horizontal/vertical well combinations experiment was closer to the actual field curve · California reservoirs: gravity flow with steam than the numerical simulation · Tangleflags field project design · SAGD studies EXAMPLES OF SAG

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