Reserch On Complex Thermal Fluid Stimulation Well Test Technology For Heavy Oil

Complex thermal fluid stimulation is an emerging thermal stimulation with simultaneous injection including CO2, N2, steam and hot water. Complex thermal fluid well test is one of the few methods of dynamic measurements of thermal recovery and also is the direct foundation of design adjustments of heavy oil reservoir. However, there is not available and proper theory and method for complex thermal fluid stimulation well test interpretation of vertical wells, as well as horizontal wells. Basing on the temperature and pressure inspection data and seepage mechanism of heavy oil thermal recovery, we built and solved the mathematical models. The laws of pressure response during soaking and production were analyzed and concluded. We documented the well test interpolation software and established the corresponding interpolation process for soaking and production respective. The main innovative and important research results are as follows:Considering the particularity of complex thermal fluid stimulation, like multiphase, change of temperature and phase and the correlation between viscosity and temperature, the form of pseudo pressure function is selected. To solve the theory pressure during the soaking and production process, an idea and corresponding mathematical method is established by which transfer the pseudo pressure function to pressure function. Its foundation is the monotone varied of pressure during soaking and production process.At present, the vertical well heavy oil thermal recovery model is considered as the composite features of viscosity partition without considering the influence of carbon dioxide and nitrogen dissolution to fluid density and continuous phase change of multi-phase flow field underground. The vertical well test model for complex thermal fluid and high temperature production process was built by introducing pseudo pressure function. The semi-analytical solution solved by using pseudo pressure function translation method.The horizontal well thermal recovery mathematical model in heavy oil reservoirs is not considering the composite features caused by plane and vertical thermal conductivity. Aimed this problem, the heat affected zone of horizontal well is assumed as a cylinder which axis is horizontal section. With this hypothesis, the method to calculate the bottom hole pressure of horizontal well during soak and high temperature production processes in heavy oil reservoir can attribute to the superposition of a plate source point-source function and a line source point-source function, a complex thermal well test model for horizontal well was built and semi-analytical solution solved.The laws of pressure response during soaking and production were analyzed and concluded. The sensitive factors for soaking process are permeability, thermal radius, steam dryness, temperature and injection length. The sensitive factors for production process are permeability, thermal radius and production length.On the foundation of theoretical study, complex thermal fluid well test software is compiled. The interpretation of soak of complex thermal fluid in heavy oil reservoir and high temperature production process is completed.