It took 6 billion yuan (923 million U.S. dollars) of investment and more than three years for China State Shipbuilding Corp. (CSSC), the contractor, to build the CNOOC 981 rig for the offshore oil giant.

The platform is 114 meters long, 90 meters wide and 137.8 meters high, and weighs 31,000 tonnes. With a deck the size of a standard football field, the rig is capable of undertaking an offshore operation at a maximum water depth of 3,000 meters and drilling a length of 12,000 meters, according to CSSC.

Equipped with third-generation dynamic and global positioning systems, the CNOOC 981 can withstand the vibrations brought by a massive typhoon.

Zhang Guobao, director of the Committee of Experts with the National Energy Commission, said the successful construction of the rig would have a strategic significance for China to boost deepwater oil drilling capability and help secure national marine resources.

“It will also help achieve the goal set by our national strategic plan,” said Zhang, former head of China’s National Energy Administration.

China relies on imports for more than half of its oil consumption, so it’s eager to diversify its energy sources on land and through deepwater drilling to fuel its robust economic growth.

Wang Yilin, Chairman of CNOOC, said the company sees the delivery of the jumbo rig as a good opportunity to strengthen its efforts in deepwater oil exploration and ensure energy security for the country.

According to CNOOC, the rig will be installed in waters of the South China Sea and begin oil and gas prospecting in July.

The South China Sea is one of the most important natural gas and oil production bases for CNOOC, which produced more than 50 million tonnes of oil equivalent in China’s marine areas last year.

CNOOC plans to invest 200 billion yuan and drill 800 deepwater wells and raise its deepwater oil and gas output to 500 million oil equivalent by 2020.

China imported 84.96 million tonnes of crude oil in the first four months this year, up 11.5 percent from a year earlier, while imports of refined oil products rose 18.6 percent year-on-year to 14.25 million tonnes in the period, according to government statistics.