Analysis Of Production String Mechanics In Horizontal Thermal Recovery Wells

There are abundant heavy oil reserves oil in our country,and thermal recovery method is adopted.During hot steam injection process,temperature of annulus fluid and strings increase,leading to annular pressure buildup(APB).Besides,the thermal stress has great influence on the production string integrity.Therefore,the horizontal well annulus fluid and tubing temperature analysis of heavy oil thermal recovery,the mechanics and prediction of APB,research of production string force load changes have great significance to ensure the integrity of the production string.In this paper,the heat transfer theory and the law of energy conservation are used to establish the temperature field model in thermal recovery horizontal well,and the temperature field under steam injection operation is predicted.The calculation results show that under the steam injection condition,the average temperature of C annulus increases higher than that of other annulus,and the temperature drop rate of wellbore decreases continuously.Based on the established temperature field,considering the influence of the axial thermal stress,the coupling effect of the multi annulus and the casing displacement in the cementing segment,the prediction model of the pressure buildup with dual packers is established.Through the example calculation shows that the C annulus APB increases higher than the others.Tube Mises stress is within its yield limit,but the safety factor is low,the packers has not reached its limits,;After taking measures of N2 injection,the APB decrease 44%,improving the safety of tubingBased on the linear variation of the axial temperature of the production string,unequal spacing installation method of the thermal stress compensator is designed to optimize the position of the compensator.According to the case,production string thermal stress is significantly reduced compared to the isometric spacing installation method.In order to verify and modify the prediction model of the multi annulus pressure buildup,the simulation device and experimental scheme for APB are designed in this paper.