The Finite Element Analysis of Stress-Seepage-Temperature Three Field Coupling of Thermal Recovery Well in Heavy Oil Reservoir

摘要

In the oil and gas extraction process, especially in the high-pressure water or heavy oil thermal recovery processes, reservoir pressure and temperature are constantly changing, which results to the deformation of porous medium, and the reservoir deformation would affect the variations of reservoir pressure and temperature.The interaction between the fluid flow of reservoir pore, temperature changes and the rock deformation is called the seepage-stress-temperature three coupling problem.Put the rock mechanics, heat transfer, fluid mechanics, petroleum engineering and reservoir physics together, establish the temperature, seepage and stress fields coupling theory mode.Take thermal recovery wells for example with finite element analysis, studied the law of stress-strain variation with time and space and the law of dynamic variation of petrophysical parameters.The results showed that: the closer from the wellhole, the more significant changes in rock strain, porosity, permeability, compression factor of porosity and other physical parameters;the farther away from the wellhole, the change is less obvious.The change of physical parameters under the coupling condition is smaller than the uncoupled condition.The oil production under the coupling condition is less than the uncoupled condition, which is mainly due to the fluid-solid-thermal coupling effect.The seepage resistance is increasing when fluid flows through rocks, which makes oil production decreased.The establishment of this model gives the theoretical basis for analyses of numerical simulation of thermal recovery, the ground thermal recovery wellbore stability and subsidence caused by mining.