China National Offshore Oil Corp's breakthrough in offshore heavy oil thermal recovery has unlocked access to a vast reserve of previously inaccessible heavy oil, bolstering China's energy security and reducing its reliance on imports, said industry experts.

CNOOC announced on Saturday that its offshore heavy oil thermal recovery solutions — including 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 marks China as the first country in the world to achieve large-scale thermal recovery development of offshore heavy oil, said Lin Boqiang, head of the China Institute for Studies in Energy Policy at Xiamen University.

It is a pivotal moment for China's energy landscape and the global oil industry by not only enhancing domestic production capabilities but also positioning CNOOC as a potential exporter of this specialized technology, he 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 with onshore oilfields, offshore platform operations have limited space and high costs. The large-scale development of heavy oil thermal recovery faces challenges in terms of technology, equipment and economic benefits, and is recognized by the industry 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, said CNOOC.

Lin believes CNOOC's breakthrough in offshore heavy oil thermal recovery represents a significant step forward for China's energy sector.

CNOOC's achievement in offshore heavy oil thermal recovery is a strategic win for China's energy security. As global oil demand continues to rise, unlocking previously inaccessible heavy oil reserves becomes increasingly critical, he said.

The company's technological advancements not only enhance its own production capabilities but also position it as a potential exporter of this specialized technology to other nations with significant heavy oil resources, he added.

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 increasing domestic oil and gas exploration and development efforts, said CNOOC.

This year, heavy oil thermal recovery production has exceeded 1.3 million tons and annual production is expected to jump to 2 million tons, it said.

CNOOC is actively involved in heavy oil production, notably with its new Kenli 10-2 oilfield project, the first lithological oilfield with a proven in-place volume of 100 million tons discovered in the shallow depression zone of the Bohai Bay Basin, which commenced heavy crude production in July.

This project, equipped with over 240 sets of key equipment, utilizes both conventional and thermal recovery techniques to produce the viscous, high-density oil.

As one of the most complex production platforms in the Bohai region and the first large-scale thermal recovery platform for heavy oil in the southern Bohai Sea, it is expected to achieve a peak production of about 19,400 barrels of oil equivalent per day in 2026, said CNOOC.

The main production facilities include a new central platform and two wellhead platforms, which leverage the adjacent existing facilities for development, it said.

CNOOC has been stepping up efforts to boost China's domestic heavy oil production and has the distinction of leading in large-scale offshore heavy oil thermal recovery technology.

The successful commencement of production of this project marks a new stage in the development of complicated heavy oil reservoirs offshore China, CNOOC said.

"It will strongly support the company's Bohai oilfield to achieve the annual gross production target of 40 million tons, contributing to the company's high-quality development through high-level operations."