Abstract Constructability Risk Management is essential in every project, especially in the upstream oil and gas industry as it covers many stages from concept design to execution at offshore. Hence, understanding of constructability and installability for offshore brownfield modification is crucial. This paper was initiated to address the tacit knowledge, lack of guidelines and scattered references related to offshore brownfield modification project. This paper will provide a guideline on a standardized approach and methodology for structural modification on offshore platforms covering design, onshore construction, offshore installation, and hook-up perspectives based on best practices and lesson learnt comprising platform assessment, cost-benefit analysis exercise and constructability study. The findings were then used to deliver optimized, effective, and safe offshore execution plan. Ultimately, SCOBI will contribute towards sustainable modification project covering cost, schedule, governance, safety, and environment.