This paper aims to optimize the injection temperature and pressure of supercritical steam. For this purpose, the author acquired the variations of the supercritical steam parameters (i.e. density, viscosity, thermal conductivity, enthalpy and specific heat) with temperatures and pressures, plotted the 3D diagrams of the variation patterns, and performed surface fittings of the results. On this basis, the calculation formulas were put forward for the physical parameters of steam under changing temperature and pressure. According to the theories of heat transfer, thermodynamics and fluid mechanics, a mathematical model of wellbore temperature and pressure was created for supercritical cyclic steam simulation (CSS), and discretized the calculation formulas by node analysis. Based on the model, a computation software was compiled for supercritical CSS, and applied to calculate the variation in wellbore temperature and pressure with well depths. The results show that the calculated temperature of wellbore steam decreased linearly, while the calculated pressure of the steam increased linearly, with the increase of well depth. Through comparison, the calculated results were found to be consistent with the distribution curves of the test results. The error between the two sets of results is extremely small. The research findings shed new light on the design and optimization of supercritical CSS parameters.
supercritical cyclic steam stimulation (CSS), Wellbore temperature, Wellbore pressure
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