Conductor-Moored Minimal-Facilities System Teamed with Dual Small CNG FPSOs: Results from a South African Case Study and Applicability to South-East Asia

Abstract Offshore gas fields located in moderate water depths and far from existing midstream infrastructure frequently stall on cost, complexity, and time‑to‑market. This paper presents engineering and economic results from a feasibility study for a conductor‑moored minimal‑facilities subsea production system ("conductor‑moored tree") integrated with a two‑vessel, small Compressed Natural Gas (CNG) FPSO shuttle concept. The case study is South Africa's Block 2A in the Orange Basin (200–270 m water depth; approximately 60 km to shore), where gas quality is favorable (low CO₂, no H₂S; low condensate/gas ratio) and discovered volumes are compartmentalized across multiple geo‑bodies. Two "Handy‑sized" CNG FPSOs (<50,000 DWT) alternate between (1) on‑station production, separation, compression and storage and (2) shuttle to shore for offload, enabling continuous export without fixed pipelines or large subsea spreads. Simulations and concept costing indicate technical and economic viability, a step‑change reduction in CAPEX/ABEX, time to first gas, and execution risk, and a phased path across multiple reservoir geo‑bodies. The paper concludes with a transferability framework for applying the concept to South‑East Asia's archipelagic, small‑to‑mid gas resources and power markets.