The Research Of Casing String Strength Design In Deep Well

With the expanding of petroleum exploration and the development of increasing exploration depth now, an increasing number of deep wells and ultra-deep well, and with an increasing casing depth, Stress and distortion of casing become more complex. So it’s requirement consideration for a more comprehensive in casing design. This article is based on previous research and combined with the characteristics of casing string in deep well, research the calculation of casing strength in the deep well and the casing load distribution along the depth, according to the theoretical prepare for a set of practical casing string strength design software finally.In this paper, according API casing strength, detailed study the casing string triaxial stress intensity and the impact of bend to the casing collapse strength. According to the different types of casing and borehole trajectory and method of calculation, calculate the axial force and external pressure and internal pressure along the depth distribution along the well depth. Set up the axial force model of the casing string in the vertical well, two-dimensional borehole and three-dimensional borehole, and the computing model of the additional axial force by bending. It is also considerate the impact of high temperature to the casing strength.On the basis of the system study, program a software of "casing string strength design in deep well" using C#language on the Visual Studio application platform, It user friendly and simple operation and flexible computing, powerful date management capabilities.