Patent ID: 9638023
Date: 2017-05-02
CPC Classifications: E21B,G01L

Claim:
1. A method for determining stresses in a pipe under non-uniform exterior loads, which comprises: a) determining coefficients in multiple stress equations for the pipe by solving boundary condition equations using a maximum lateral pressure on the pipe, a minimum lateral pressure on the pipe, an inside radius of the pipe and an outside radius of the pipe; b) solving two of the multiple stress equations that each represent a radial stress for the pipe, two of the multiple stress equations that each represent a hoop stress for the pipe, which are added together to represent a total radial stress and a total hoop stress, and one of the multiple stress equations that represents a total shear stress for the pipe using one or more of the coefficients, a predetermined pipe radius and a predetermined pipe angle; c) calculating a stress intensity for the pipe using a computer processor, the total radial stress, the total hoop stress, the total shear stress and a predetermined total axial stress for the pipe, d) repeating steps b)-c) with another predetermined pipe radius and another predetermined pipe angle until a maximum stress intensity for the pipe is calculated; e) selecting the pipe based on the maximum stress intensity for the pipe; and f) installing the selected pipe in a wellbore.