China’s Large-scale Offshore Oilfield Starts Full Production in Bohai Sea

Xinhua News Agency reports that the first phase of China’s Kenli 10-2 oilfield cluster, a 100-million-ton-level offshore oil project in the Bohai Sea, has officially commenced full operation on May 27. As China’s largest shallow lithological oilfield offshore, the site delivers a daily crude oil output exceeding 2,800 tonnes, reinforcing stable domestic offshore energy production capacity.

Located in the southern waters of the Bohai Sea, Kenli 10-2 oilfield holds proven geological reserves of over 100 million tonnes. The first-phase development comprises one central processing platform and two unmanned wellhead platforms, with a total of 79 development wells deployed. It marks the country’s first attempt to develop dendritic heavy oil reservoirs with thermal recovery technology in the Bohai Sea, filling technical gaps in the development of complex offshore oil-bearing formations.

The oilfield features unique dendritic heavy oil reservoir structures, where oil and gas are stored in intertwined narrow and curved sand bodies. Its reserve distribution presents scattered, narrow, thin and complex characteristics, bringing unprecedented challenges to construction and exploitation. The project also faces multiple technical difficulties including diverse well types, layered systems and flexible development modes, with no mature industrial experience for reference.

To tackle complex geological conditions, the project team adopts a targeted refined development strategy. A tailored well network design is implemented for each sand body and reservoir, with customised operational plans formulated for every single well. Drilling procedures are optimised to ensure safe and efficient progress, while differentiated well completion technologies are applied based on reservoir features. Synchronised multi-disciplinary operations guarantee stable thermal injection for 24 designated wells, achieving successful one-time startup of the first round of pumping.

China National Offshore Oil Corporation’s Tianjin branch has built an integrated development model for large-scale oilfields, enabling immediate production after well completion and accelerated operational efficiency. Innovative refined reservoir description technologies greatly improve identification accuracy for thin oil layers. A combined development mode integrating conventional water injection, steam huff-puff and steam flooding is adopted to realise efficient and balanced utilisation of oil reserves. Advanced annulus liquid level monitoring technology is deployed at operational sites to track formation pressure in real time, supporting precise reservoir analysis and refined thermal recovery management.

All 33 cold production wells and 24 thermal recovery wells in the first-phase project have completed pumping startup. The technological system summarised from the project provides replicable solutions for the development of similar complex heavy oil reservoirs. The fully operational oilfield will underpin sustained stable output growth of the Bohai Sea oilfield, China’s largest crude oil production base, and consolidate domestic offshore energy supply capabilities.