(Adds details on Sinovensa sale, background on Maduro's China visit)
CARACAS, Sept 18 (Reuters) - Venezuela has sold 9.9 percent of shares in oil joint venture Sinovensa to a Chinese oil company, President Nicolas Maduro said on Tuesday, adding the OPEC nation expected some $5 billion in joint investment with China to boost its crude output.
He did not say how much Venezuela received or which company bought the shares in Sinovensa, which is partly owned by state-owned China National Petroleum Corporation (CNPC). China will own 49 percent in Sinovensa after the sale, he said.
Maduro traveled to China, his key foreign financier, last week in search of fresh funds for his cash-starved government, which is presiding over a grueling economic depression. But it remains unclear whether he secured any new credit lines.
Maduro said the Sinovensa sale formed part of plan to invest $5 billion over the next year in Chinese projects to double oil production and be able to send a million barrels per day to China. Venezuela's oil production is at a 60-year low after years of little investment and crumbling infrastructure.
Speaking at a news conference, Maduro complained about media coverage that has portrayed the four-day trip as unsuccessful.
"They are all going to say the same: Maduro went to China and found nothing, they mistreated him," he said. Instead, he said, they had sealed a "very important deal."
Over a decade, China invested over $50 billion in Venezuela through oil-for-loan agreements, securing energy supplies for its fast-growing economy while bolstering an anti-U.S. ally in Latin America.
The flow of cash halted nearly three years ago, however, when Venezuela requested a change of payment terms amid falling oil prices and declining crude output that pushed its state-led economy into a hyperinflationary collapse.
Asked by reporters on Tuesday whether Maduro had asked for a new grace period to meets its debt obligations with China, he said "Venezuela pays on time."
Maduro on Tuesday said he could count on China as an ally to survive an "economic war" he accuses the United States of waging against Venezuela. U.S. President Donald Trump's administration has levied several rounds of sanctions on Maduro's government. (Reporting by Brian Ellsworth and Corina Pons Writing by Angus Berwick Editing by Marguerita Choy)