关键词: 稠油油藏, 蒸汽热采, 热-流体-力学耦合模型, Galerkin有限元, 应力应变分析, 热对流

Abstract: In order to solve the high viscosity problem of the crude oil, the steam stimulation technology is generally adopted in heavy oil reservoir exploitation. Based on the continuum mechanics theory, an improved thermal-hydraulic-mechanical coupling model which considers the influence of heat convection is established to quantitatively evaluate the formation pressure, deformation and effective stress under steam injection conditions. The Galerkin finite element method with the fully implicit and sequential algorithm is used to simulate the thermal-hydraulic-mechanical coupling process around the injection well. The results show that the high pressure which is caused by the higher thermal expansion of fluid may lead to displacement, deformation or even failure of structure; and the temperature has a great influence on the fracture geometry of the formation. The study indicates that this enhanced model is more exact and practical than the classic method and can be applied to optimizing the steam injection rate, investigating the combined effects of the reservoir, geology, thermal-hydraulic response, in-situ stress, etc.

Key words: heavy oil reservoirs, steam stimulation, coupled thermal-hydraulic-mechanical model, Galerkin finite element method, stress and strain analysis, heat convection