Abstract A marginal field off the coast of East Malaysia has a low recovery factor, yet it holds a substantial amount bypassed hydrocarbons within the shallow high-angle and depleted reservoirs, conditions that make conventional drilling economically unfeasible. Coiled Tubing Drilling (CTD) was identified as a cheaper alternative to access these reserves. However, the requirement for a dedicated vessel to reach the remote unmanned platforms significantly increases project costs and operational risks. To tackle this challenge, the project team implemented a phased strategy that separate the preparatory activities from the drilling campaign. This approach aimed to reduce NonProductive Time (NPT), enhance the efficiency of vessel utilization and de-risk operations. The preparation phase began with a multidisciplinary subsurface assessment to select suitable candidates. Screening criteria included reservoir quality, remaining reserves, well integrity, well/platform accessibility, artificial lift consideration/issue and future intervention potential. Once candidates were selected, a detailed feasibility study was conducted to assess operational viability. This study encompassed platform site visits to evaluate space and lifting constraints, equipment layout planning and readiness assessments. In addition, technical reviews addressed fluid system design tailored to reservoir conditions, completion and cementing strategies, and trajectory optimization to ensure maximum reservoir contact and optimize well productivity while mitigating operational risks. This structured and integrated approach highlights how CTD can be systematically applied in Malaysian offshore marginal fields to deliver technically robust, cost-efficient and operationally safe outcomes, while ensuring alignment with broader long-term field development goals. The paper further discusses lessons learned, best practices and forward plans from these campaigns to guide future CTD applications in similar environments.
Hamid et al. (Mon,) studied this question.