Study On Steam Chamber Expansion Of Steam-assisted Of Gravity Drainage

China is rich in heavy oil resources. As the crude oil resource shortage appears, the development of heavy oil attracts much attention. Now Steam-Assisted of Gravity Drainage is an effective method for thermal recovery technology on developing heavy oil. The formation and extension of steam chamber is the key to Steam-Assisted of Gravity Drainage, and so it is meaningful to study on steam chamber expansion of Steam-Assisted of Gravity Drainage.In the paper, we first explored the basic principle of SAGD technology, and then set up the shape equation of steam chamber expansion by studying its boundary steam overlaying phenomenon. We analyzed how the steam injection velocity affects the shape coefficient of steam chamber boundary. According to studying the heat and mass transfer law on the boundary of steam chamber expansion, the relationship among vertical dimension, lateral advance velocity and unit boundary thermal storage are obtained. We established dual horizontal wells SAGD steam chamber expansion mathematical model on the basis of Butler drainage theory, and then analyzed all the factors that influence vertical expansion time of steam chamber. In the meantime, we evaluated the susceptible influence on steam chamber expansion drainage effect.According to the reservoir geological data, numerical models were created and simulated SAGD steam chamber in the change of temperature, pressure and oil saturation, and simulation results and the numerical results have good coincidence with field data, which validate the correctness of the mathematical model and numerical simulation. And then we explored impact of reservoir geological conditions and injection-production parameters on SAGD steam chamber expansion and production. Moreover, we optimized influential factors by using orthogonal optimization method. To explore the regularity of nitrogen-assisted SAGD steam chamber expansion by numerical simulation method, we make comparative analysis between nitrogen-assisted SAGD and SAGD in energy dissipation, in accord with optimizing the nitrogen gas and steam-injection ratio.In the paper, we study on the SAGD steam chamber expansion laws by ways of mathematical models and numerical simulation, which provide theoretical basis for further optimizing steam chamber expansion and improving oil recovery effect.