FEM Analysis of Fluid-Structure Interaction in Thermal Heavy Oil Recovery Operations

In the process of heavy oil thermal recovery, the creep of strata can often be accelerated due to injection pressure, the temperature of steam, the structural characteristics of rock itself and other factors. However, the effect of creep in strata may cause various types of damage in underground mining, such as fracture or deformation of oil casings, and so on. The mechanism of fluid-structure interaction provides a powerful theoretical guidance for stratum creep, which happens during the process of heavy oil thermal recovery. According to existing research, a practical engineering finite element model of Jin.25 Block in Liaohe Oilfield was built based on the finite element analysis software ADINA, and the numerical simulation of the thermal recovery stratum creep of Jin.25 Block was done using the fluid-structure interaction (FSI) calculation module. The results were compared and analyzed, combining each influencing factor of the stratum creep in practical engineering. It is proposed that steam injection pressure should not exceed 14 MPa while enhancing oil recovery by increasing the injection pressure; the main reason is that temperature impact on casings is closely related to the change in stratum creep stress. However, particular attention should be paid to the thermal sensitivity of casing itself and creep deformation when the hydraulic conductivity magnitude is above 1 x 10(-9) m/s, so as to effectively prevent or minimize the economic loss caused by stratum creep.