China discovers major offshore deep to ultra-deep clastic oilfield

(ECNS) – The China National Offshore Oil Corporation (CNOOC) announced on Monday the discovery of the Huizhou 19-6 oilfield in the eastern South China Sea. It is China's first large-scale deep to ultra-deep clastic oilfield, underscoring the potential for deepwater hydrocarbon exploration in offshore areas.

Located in the Huizhou Sag of the Pearl River Mouth Basin, about 170 kilometers from Shenzhen, the oilfield lies at an average water depth of 100 meters. Test drilling has yielded a daily production of 413 barrels of crude oil and 68,000 cubic meters of natural gas. Proven geological reserves have been confirmed to exceed 100 million metric tons of oil equivalent. 

According to the CNOOC, deep to ultra-deep offshore exploration poses challenges such as high temperatures, high pressures, and complex conditions. Clastic reservoirs, a key component of deep-sea hydrocarbon deposits, generally have low permeability, making the identification of large oil and gas fields more difficult.

Peng Guangrong, a geologist at CNOOC's Shenzhen branch, noted that 60 percent of the world's newly discovered oil and gas reserves in recent years have come from deep formations. Compared to shallow and mid-depth reservoirs, deep to ultra-deep formations exhibit higher temperatures and pressures, greater hydrocarbon maturity, and closer proximity to source rocks—conditions that are favorable for the formation of natural gas and light oil. These deep reservoirs remain largely unexplored and are expected to drive future growth in oil and gas reserves and production.

China's offshore oil and gas exploration has achieved consecutive breakthroughs, with discoveries exceeding 100 million tons for two straight years, said CNOOC CEO Zhou Xinhui. The company plans to further expand exploration and development efforts to reinforce the resource base for sustained production growth.