| Sea thermal recovery Wells with high temperature fluid injection,It’s easy to cause the casing string up or damage and threat to wellhead platform security seriously.Therefore,the study of thermal recovery Wells wellbore temperature field and stress field of casing,cement loop system,predict different stages wellhead string growth height,choice the reasonable wellhead,reduce the string damage degree,has a profound significance for thermal recovery Wells on the sea.This paper applied the theory of heat transfer,considering the environment of sea,established wellbore temperature field calculation model for thermal recovery Wells,and the different operation stages of wellbore temperature field is forecasted.After getting the wellbore temperature field distribution,considering wellhead activity near period of cement ring of string friction constraints,set up wellhead growth calculation model finally;considering the accumulation of high temperature and residual stress of casing damage section of tubing string,analysis the main mechanism of casing damage;Considering the screen along with the end to the toe of the linear temperature change,calculated the minimum compensation for the screen integrally,and optimized the installation location of thermal stress compensators.For solving the wellhead growth and related parameters in the calculation model,this paper designed the thermal recovery Wells casing-cement ring mechanics parameters test experiment devices.Through calculation of temperature field and compared the measured point,the error is less than 5% and meet the accuracy requirements.The volume of the maximum error between calculation results of wellhead growth and the measured results is 4.64%,this model can be used as the basis for optimizing wellhead. |
