China Achieves 3000m Breakthrough with Subsea Electromagnetic Tech Deepwater Oil and Gas Exploration Sets Three Industry Firsts

China’s homegrown high-power controlled-source subsea electromagnetic (EM) exploration technology has achieved successful industrial demonstrations in deepwater regions such as Liwan, Liuhua, and Lingshui. This milestone signals a leap forward in offshore oil and gas detection, opening innovative solutions for exploring complex deepwater reserves.

Traditional offshore oil and gas prediction relies mainly on seismic methods, which, while offering high vertical resolution, are less sensitive to hydrocarbon saturation and can yield ambiguous results. In contrast, subsea EM technology leverages underground resistivity to identify oil and gas, providing enhanced sensitivity to reservoir saturation. By integrating seismic and EM data, exploration teams can more accurately map and distinguish high-saturation reservoirs, significantly improving reliability.

The latest demonstration set three world firsts:

• Achieved 1,900-ampere supercurrent excitation, pushing the effective detection range to 15 km (up from 8–10 km) and probing depths down to 3,000 meters.
• Overcame deepwater terrain challenges, using real-time dynamic source control to maintain towing just 30–40 meters above rugged seabeds at depths of 1,500 meters.
• Set a new precision record for receiver deployment in complex ocean currents, keeping positioning errors within 5% of water depth.

Jointly developed by CNOOC Research Institute, Ocean University of China, and China University of Geosciences (Beijing), this next-generation EM system will boost the success rate of deepwater exploration and reinforce China’s energy security and marine economic growth through technology innovation.