Stress Analysis Of Outside Upset Casing In Thermal Recovery Well

At present in our country during viscous crude recovery, owing to the influent steam has high temperature and pressure, under high thermal stress and other factor, the casings are badly damaged, therefore the closed wells get more and more. So we carry the analysis of casing damage, stress and intensity, the numerical simulation of temperature field and stress field of steam input well, the research of the casing stress effect come from wall thickness change, through in-house experiment , theory and analysis of numerical simulation. Through actual data conclusion, numerical calculation and theoretical analysis, we can get the conclusion: the main reason of casing damage is the effect of unequal loading; through decrease the coefficient of thermal conductivity of heat insulated tube ,the casing can be effectively protected; the temperature field is higher near the joint of heat insulated tube than other average temperature of tube body; the effective stress numerical value has something to do with wall thickness dimension and casing pressure, the effective stress of upset casing is lower than that of normal casing, the resistant collapsing intensity is more strengthening, the bearing capacity is better than before. When casing pressure below 25MPa, with the casing pressure gets higher and higher , the effective stress of normal casing and upset casing gets lower and lower. But when casing pressure above 30MPa, with the casing pressure gets higher and higher, the effective stress of normal casing and upset casing gets higher and higher. AS to the wells that internal pressure changes are bigger than others, upset casings have more bearing capacity. The above conclusion has provide theory foundation for design, test and development of new outside upset casing, along with design means of composite new outside upset casing string in viscous crude oil well and design of software.