
CNOOC Ltd. said Wednesday it had achieved another “major breakthrough” in the exploration of buried hills in the South China Sea after drilling 3,362 meters (11,030.18 feet) deep in the Weizhou 10-5 South field.
The field is in the Beibu Gulf, or the Gulf of Tonkin, in waters with an average depth of 37 meters, according to CNOOC Ltd., majority-owned by the state’s China National Offshore Oil Corp.
Exploration well WZ10-5S-2d showed a 211-meter oil and gas pay zone. Tests yielded a production of 165,000 cubic feet of natural gas and 400 barrels of oil per day, CNOOC Ltd. said in a press release.
The well “marks a major exploration breakthrough in the metamorphic sandstone and slate buried hills offshore China”, the announcement declared.
“In recent years, CNOOC Ltd. has consistently intensified theoretical innovation and tackled key technology challenges in buried hills and deep plays exploration”, commented CNOOC Ltd. chief geologist Xu Changgui. “Breakthroughs have been achieved in the exploration of Paleozoic granite and Proterozoic metamorphic sandstone and slate buried hills within the Beibu Gulf Basin.
“They demonstrate the vast exploration potential in buried hills formations, drive the secondary exploration process in mature areas, and mark the commencement of large-scale exploration of buried hills in the Beibu Gulf Basin”.
CNOOC Ltd. chief executive Zhou Xinhuai added, “In the future, CNOOC Ltd. will continue to intensify research on key theories and technologies for deep play exploration, to enhance research and development capabilities, advance reserves and production growth, and to ensure stable supply of oil and gas”.
In March CNOOC Ltd. claimed a breakthrough in the exploration of Paleozoic granite buried hills in the Beibu Gulf through an oil and gas discovery in the Weizhou 10-5 field.
Drilled to a total depth of about 4,840 meters in an area with an average water depth of 37 meters, well WZ10-5-1Sa showed a pay zone of 283 meters. During testing the well produced around 13.2 million cubic feet of gas and approximately 800 barrels of crude per day.
“It marks a major breakthrough in natural gas exploration in the granite buried hills in the Beibu Gulf Basin”, CNOOC Ltd. said.
In February CNOOC Ltd. announced the start of production in what it said was the globe’s largest metamorphic buried-hill oilfield.
Producing light crude, Bozhong 26-6 is expected to reach 22,300 barrels of oil equivalent a day in peak production this year. The field, which has an average water depth of about 20 meters, holds over 200 million cubic meters (7.06 billion cubic feet) of proven oil and gas in place, according to CNOOC Ltd.
“Benefiting from the application of standardized engineering, it took only three years from the discovery of the oilfield to production, realizing the rapid conversion of reserves to production”, it said.
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