As a result of presence of mobile seabed, the route of the Nam Con Son 2– Phase 1 Gas Pipeline was subject to numerous span formation. During survey of the pipeline , a total of 2534 free spans were identified. Based on Level 1 and Level 2 span assessments in accordance with DNV-RP-F105, the spans which needed Level3 assessments were identified. Moreover 68 of these span clusters consisting of more than one spans were found to be interacting. L3 assessments were performed for these spans using Abaqus FE software and fatigue life were calculated for these spans to determine their fatigue life. Recommendations were made to perform groutbag rectifications of the spans whose fatigue life was lower than the stipulated minimum fatigue life.