CNOOC Discovers Significant New Oil and Gas Reservoir in South China Sea

On Sunday, China National Offshore Oil Company (CNOOC) announced the discovery of a significant new field in an undisputed area of the South China Sea. 

The Huizhou 19-6 oilfield is located in the eastern part of the South China Sea, about 150 nautical miles off Shenzhen - far away from geopolitical hotspots and well within the Chinese exclusive economic zone. CNOOC assesses that it contains 750 million barrels equivalent of oil and gas (100 million tonnes). The test well produced minimal daily oil production and 2.4 million cubic feet of natural gas per day. It is a shallow-water field with a water depth of just 100 meters, but drilling the deep well of 5,400 meters was a technical challenge, said Xu Changgui, chief geologist for CNOOC. 

"This discovery has confirmed the largest integrated clastic oilfield in the northern South China Sea in terms of original oil in place, breaking the traditional theoretical understanding, and demonstrating the enormous exploration potential of deep and ultra-deep plays in high-temperature and highly active basins offshore China," said Xu. 

The find marks the second year in a row that CNOOC has found a resource this big. If commercialized and replicated at scale, it could help China reduce its dependence on foreign gas imports. China buys about 10 billion cubic feet of gas in the form of LNG every day - nearly three shiploads daily. 

Clastic reservoirs like Huizhou 19-6 are a challenge for oil and gas development, and are more complex and less predictable than other plays. They are formed from deposits of geologic debris, like sand, rock fragments, clay and minerals, and often vary in composition throughout the formation. 

Top image: CNOOC headquarters, Beijing (Daniel Case / CC BY SA 3.0)