World's Largest Metamorphic Buried-Hill Oil Field Completes Phase II Platform Construction with Welding Robots

All platforms for the Phase II development of the Bozhong 26-6 oil field — the world’s largest metamorphic buried-hill oil field — have completed onshore construction and been loaded out for sea transport, according to CNOOC Offshore Engineering. The final platform departed from the company’s Tianjin intelligent manufacturing base, paving the way for the field’s scheduled commissioning.

Located in the central Bohai Sea, the Bozhong 26-6 field holds cumulative proven oil and gas geological reserves exceeding 200 million cubic meters. Phase I of the development entered production in 2025, and the field also serves as CNOOC’s flagship carbon capture and utilization demonstration project in the Bohai Basin — carrying the triple mission of energy supply security, green transition, and scientific research, with significant implications for the energy security of the Beijing-Tianjin-Hebei and Bohai Rim regions.

The Phase II project involves the construction of two new wellhead platforms at sea, each consisting of a jacket structure and a topside module. Both platforms are designed for fully unmanned operation, eliminating the need for permanent on-site personnel and representing a significant step forward in intelligent offshore facility management.

The project achieved a 100% integrated installation rate for module columns, braces, wall panels, and support frames through a combination of modular design, prefabricated production, and digital assembly techniques. In a notable innovation, the construction team deployed welding robots with customized tooling and optimized programming, which effectively resolved welding defects such as porosity and lack of fusion. The robotic system boosted overall welding efficiency by 20% and enabled standardized batch manufacturing of intermediate products — a milestone for automated fabrication in China’s offshore engineering sector.

With all platforms now completed and shipped, the Bozhong 26-6 Phase II project moves closer to its production target, underscoring CNOOC’s growing capabilities in intelligent manufacturing and unmanned offshore operations.