China's largest oil and gas producer, China National Petroleum Corporation (CNPC), signed an agreement on Friday with Qinghai provincial government to invest 23 billion yuan (3.37 billion U.S.dollars) in the province over the next five years.

The investment is to boost CNPC Qinghai oilfield's production to at least 8.5 million tons per year by 2015, said Wang Yilin, a deputy manager of CNPC.

The CNPC Qinghai oilfield produced 1.855 million tons of crude oil in 2009. CNPC also plans to raise its Qinghai retailers' annual sales to 1.5 million tons by 2015. It also has agreed to provide Qinghai with natural gas amounting to 15 billion cubic meters from 2010 to 2015, Wang said.

Further, the company, which is also the parent of PetroChina, would expand the capacity of an oil storage tank by 48,000 cubic meters while building 120 petrol stations and 40 gas stations, he added.

Qinghai's Yushu was rocked by a 7.1-magnitude earthquake on April 14. At least 2,698 people were killed while 270 remain missing. The government said it would take about three years to rebuild the flattened town of Gyegu near the epicenter.

Wang said, to ensure a stable supply of energy to the quake zone CNPC would build 12 petrol stations and a 6,000-cubic-meter oil storage tank in Yushu along with a terminal to receive liquefied gas in Gyegu.

Qinghai is home to a number of key oil and gas production bases in China's western region. By 2009, identified crude oil reserves in Qinghai topped 370 million tons while natural gas deposits were placed at 290 billion cubic meters -- only 25 percent and 11 percent, respectively, of the province's estimated total reserves.