They said Dongxin, one of the six, contains more than 252 million tons of oil while the other five areas may have between 10-30 million tons.

"The new breakthroughs will help ease the country's oil shortage considerably and especially sustain the better developed eastern areas," said Yan Jisheng, a ministry official in charge of natural resources and environmental development.

Scientists may find similar geological areas and even more oil in other parts of the country, said Yan.

The new discoveries were the results of recent advances in underground surveys developed by Chinese scientists. The process involves studying the qualities of sedimentary rocks to discover oil deposits.

Scientists combined a number of disciplines, including physics, chemistry, geology and computer science, to explore the sites where they believed oil deposits might be located.

The new theories have gained worldwide attention among geologists.

During a symposium last October in Beijing, experts called the new theories important to the development of oil resources around the globe, said ministry sources.

With its rapid economic development of the past two decades, China has been facing an oil shortage.

Since the late 1990s, output from the Daqing and Shengli oilfields -- the backbones of oil production in east China -- has begun to fall after four decades of exploitation.

Over the past eight years, scientists have applied their new theories to test for oil deposits in the Shengli Oilfield and adjacent areas. The six deposits located include up to 280 million tons of oil.

Scientists have identified other areas they intend to explore.

They believe that these newfound areas will help reverse the output decrease at Shengli. By last year, such areas around Shengli had produced over 33 million tons of crude oil.

The Shengli Oilfield is expected to keep oil production steady at 30 million tons through 2006.

The Songliao, Bohai Bay, Nanxiang, Jianghan and Subei bases in east China may contain a total of 10 billion tons of sedimentary-based oil deposits, experts said.

"These new discoveries have eased our anxiety over oil shortages... and we know that we have more oil deposits to support the country's long-term economic development," said Yan.

Meanwhile, scientists are working to apply new oil extraction technologies in old oil fields, such as Daqing and Shengli, to upgrade the efficiency of oil production, according to Yan.

(China Daily April 6, 2004)