Study On Pressure Field And Casing Deformation Mechanism Of Wellbore In Heavy Oil Thermal Recovery Well

China’s heavy oil industrial exploitation gets maturely after more than30years development. At present, heavy oil resources become the main energy because of the thin oil decrease gradually. As the steam stimulation process grows maturely and the casing damage situation becomes worse and worse and there is a huge influence on the economic benefit, It is important to analyze the mechanical properties of the casing,to realize the damage mechanism of casing and put forward appropriate prevention measures.The casing’s collapsing strength under both the uniform load and the nonuniform loading was discussed respectively and the influential factors of the wellbore-formation’s temperature field are also analyzed. In order to program the software to prediction the tempreture field of the wellbore in the steam injection thermal recovery Wells at soak stage, the basic theory of heat transfer and the energy conservation equation and the momentum conservation equation and the mass conservation equation and the prediction model of le-phase steady flow wellbore’s temperature field have been used. In the research of the heavy oil block in Xinjiang oil field, we found that the site worker do not understand the temperature distribution in the wellbore very well. Even the temperature in the wellbore is never been messured.Which is adverse to the prevention of the casing damage.It is been vilified in the field test and two groups of test data are obtained. The test result shows that the diviation is less than5%, and this software can be used in the Baikouquan heavy oil block in Xinjiang oil field.After getting the model of the wellbore temperature field, we analyze the stress of casing cement sheath by the basic theory of thermal stress, and establish the contact pressure model of casine cement sheat. We analyze the contact pressure between the casing and the cement ring and cement annulus,and the formation pressure of surrounding rock, then combined with the Xinjiang oil field well we calculate the stress and the displacement of the casing cement sheath system are affected by the stress and displacement when injecting the high temperature steam between380degrees Celsius and320degrees Celsius.In the end of the paper, the steam injection thermal recovery Wells’casing damage mechanism has been analyzed and the prevention methods of casing damage have been put forward to analyzing the pulling pre-stress calculation formula.In order to alleviate the casing damage which is very concerned effectively. This article means to use the software to predict the pressure field and the temperature field, and analyze and study the casing stress before the occurrence of the casing damage.