Patent ID: 8504308

Claim:
A method for fatigue analysis of a bottom hole assembly (“BHA”) comprised of a plurality of drill collars threadedly connected, the method comprising: obtaining, during drilling operations, measurements by sensors connected with the BHA; receiving the measurements at a terminal; generating, using the terminal, a beam model of the bottom hole assembly to determine loading conditions of at least one of the plurality of drill collars at a first dog-leg severity of a wellbore; performing, using the terminal, a finite element analysis of the one of the plurality of drill collars to determine the stresses or strains at a fatigue susceptible feature of the at least one of the plurality of drill collars at the first dog leg severity; determining, using the terminal, fatigue damage of the fatigue susceptible feature at the first dog-leg severity and at each other dog-leg severity of the wellbore; and determining, using the terminal, the cumulative fatigue damage of the fatigue susceptible feature by summing the fatigue damage at each dog-leg severity.