| Casing failures bring about a lot of losses and disasters in oil production industry every year. Causes for casing failure involve physical, chemical, mechanical functions and among which mechanical influence plays the most important role.With the help of ANSYS finite element program, an analytical model for the three-dimensional casing-cement mantle-stratum configuration is built. In the model, how those mechanical factors working on the capacity of a casing is discussed in detail and the mechanism for which the cement mantle can protect the casing from being damaged is pointed out. These achievements are beneficial to engineering design. Interface between two rock layers is built; contact element is used to simulate the slip of two layers of rock; SOLID65 element is introduced to simulate cement. According to traditional casing failure analysis method, geometry factors, material factors, and crustal stress state is discussed to analysis casing failure problem. Finally, a program for the whole analysis process is given. The main research works included in the dissertation are as following:Establish APDL program for the whole analysis process. Under the help, an engineer problem can be solved through changing the parameter of the program. In the process of writing the program, a lot of technical difficulties are solved, and the model is so accurate that it can cope with nonlinear problems including large deformation and material nonlinear attributes, though the figure change largely.With the help of simulation model, according to traditional casing failure process, factors that have influence on casing failure, such as sudden change of materials attributes; shape of a well face; contact between cement mantle and rock around the well face; material nonlinear attributes caused by fracture of cement.Write program for the process in order to put the research to practical usage. Through changing the parameter it can simulate different cases.
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