Abstract:In order to evaluate the risk of cracks on the derrick of a modular drilling rig, based on the whole finite element analysis of the derrick, the crack growth behavior is analyzed by the extended finite element method. In order to verify the structural strength of the repaired derrick, the structural check is carried out on the repaired part of the derrick, and the stress of the whole derrick is tested according to the standard. The results show that the repair plan of the derrick structure is feasible, and the bearing capacity of the derrick satisfies the requirements of design and standards.