China and Saudi Arabia reaffirmed the significance of global oil market stability and Riyadh's role in maintaining it, a joint statement said on Friday during Chinese President Xi Jinping's visit to the kingdom, the world's biggest oil exporter.

OPEC+ heavyweight Saudi Arabia is the top supplier for China, the world's biggest energy consumer, and the two sides had pledged in bilateral talks on Dec. 8 greater trade and economic cooperation as they move to deepen relations.

The OPEC+ oil producers alliance that includes Russia kept output unchanged at its last meeting on Dec. 4 as markets struggle to assess the impact of a G7 price cap on Russian oil and a slowing Chinese economy.

"The People's Republic of China welcomed the Kingdom’s role as a supporter of the balance and stability in the world oil markets, and as a reliable major exporter of crude oil to China," the joint statement carried on Saudi state media said.

It said the two sides would explore common investment opportunities in petrochemicals and enhance cooperation in renewable energy, including nuclear, and develop projects for energy supply chains, efficiency and advanced technology.

Saudi Aramco and China's Shandong Energy signed a memorandum of understanding that included a potential crude supply agreement and chemicals products offtake deal, Aramco said on Dec. 9.

It added that the two firms were exploring collaboration on integrated refining and petrochemicals in China.

When Xi first arrived in the kingdom, Saudi Arabia's energy minister said Riyadh and Beijing would seek to boost cooperation in energy supply chains by establishing a regional center in the Gulf state for Chinese factories.

Dec. 9's joint statement touched on enhancing the kingdom's location as a regional center for Chinese firms in producing and exporting energy sector products. It also raised the prospect of joint investment in energy projects in the region and "energy consuming countries in Europe and Africa."

Saudi Arabia's Crown Prince Mohammed bin Salman has launched an ambitious economic development program that includes building local capabilities across various sectors and creating new industries to reduce reliance on oil revenues.