China National Offshore Oil Corporation (CNOOC) announced on Saturday that its offshore heavy oil thermal recovery technology system and core equipment have achieved significant progress in large-scale application, with cumulative offshore heavy oil thermal recovery exceeding 5 million metric tons.

This achievement marks China as the first country in the world to achieve large-scale thermal recovery of offshore heavy oil, it said.

Heavy oil is a type of crude oil with high viscosity, high density, poor fluidity, and a tendency to solidify, making it difficult to extract.

Compared to onshore oilfields, offshore platform operations face limited space and high costs. The large-scale thermal recovery of heavy oil faces dual challenges in terms of technology, equipment and economic benefits, and is recognized as a world-class problem.

Currently, heavy oil accounts for approximately 70 percent of the world's remaining oil resources and is one of the main directions for increasing production for various oil-producing countries.

China is one of the world's four major heavy oil producers, with abundant heavy oil resources. The proven reserves of high-viscosity heavy oil that require thermal injection for development offshore exceed 600 million tons, accounting for approximately 20 percent of China's proven heavy oil reserves, indicating great development potential.

Continuously promoting the conversion of heavy oil reserves into production is of great significance for boosting domestic oil and gas exploration and development efforts, said CNOOC.

In 2025, heavy oil thermal recovery production has exceeded 1.3 million tons, with annual production expected to reach 2 million tons, it said.