The China National Offshore Oil Company (CNOOC) announced what it said is a historic discovery with more than 100 Bcm (3.5 Tcf) of proved gas reserves at the Lingshui 36-1 offshore field.
The state-owned company added that flow tests suggest the field will produce over 10 million m3/D (353 MMscf/D).
CNOOC highlighted that the certification of the reserves makes the Lingshui prospect the world’s first major ultrashallow gas field discovered in ultradeep waters.
The Lingshui field, located to the southeast of China’s Hainan Island province, is targeting a formation within the Central Sag which is a subsection of the wider Qiongdongnan Basin.
CNOOC reported the field’s average water depth at around 1500 m and said the reservoir depth of just 210 m below the mudline qualifies it as an ultradeepwater, ultrashallow gas field.
The announcement added that the anticipated offshore project to develop the field will open up a new frontier for deepwater exploration.
"Ultrashallow gas reservoirs are important sources of hydrocarbon in deep waters. However, you must overcome world-class challenges to explore and develop the reservoirs. CNOOC Limited has adopted new exploration concepts on the formation mechanism and new technological approaches to tackle the challenges,” Xu Changgui, chief geologist for CNOOC, said in a statement.
Shallow gas-bearing formations have long been known to offshore explorers, but these rock layers were typically thought to lack the structural traps needed to store significant gas volumes. However, recent seismic surveys and subsequent studies indicate that such traps do exist in certain sections of the Qiongdongnan Basin.
CNOOC, which has been exploring the region for decades, has reported several other significant gas discoveries in the Qiongdongnan Basin, as well as in the Pearl River Mouth and Yinggehai Basins. According to CNOOC, these findings collectively represent an estimated 1 trillion m3 of gas reserves.
In a statement, Zhou Xinhuai, CEO and president of CNOOC, said, “The completion of the trillion-cubic-meters gas region embodies the enormous achievements CNOOC Limited has accomplished in the South China Sea over the past 40 years. We have now embarked on a new journey to further expand the company's resource base.”
