Safe. Horizontal Well Casing Into Theoretical Research

When the casing passing the curved and horizontal section in horizontal well, there are a great of extraneous forces can be imposed on it. There are many problems that can not appeared in straight well. The casing string hug closely with the low side of well bore in the curved portion, so the great stiffness may cause freeze-in. The casing string hug completely with the low side of well bore in the horizontal section, and the long contact segment can generate great friction and cause freeze-in. As a result, sometimes the casing string impossibly tripped into the design point. Before running casing, it is necessary to calculate the possibility according to physical models.This paper concerned all of the special conditions of casing running in horizontal wells. Through analyzing the stress of infinitesimal casing string, it deduces a model, which can accurately predict the possibility of casing running in horizontal wells. The calculator program can find out the hook load and friction, and at the same time it gives two examples. The error between predictive value and measured value is about 12%, so it can satisfy the demand of project. The calculated results verified the exactness of its theoretical analysis and computational method.Through the analysis of casing string in the curved portion using the finite element analysis software ANSYS, the stress and the strain of casing string can be figured out.Meanwhile if the casing string under its material permissible resistance can be confirmed. Under the development environment of MATLAB, it developed the software of predicting the hook load and the frictional resistance in the horizontal well. This software provides a simple operation platform for the user, and it provides a good method for using and researching the casing running also. It had a certain instruction to the well cementation.