UPDATE 1-China quake hits gas output, oil impact mininal

(Adds impact on oil demand)

BEIJING, May 14 (Reuters) - A powerful earthquake that hit southwest China on Monday has shut in some 3 percent of China's gas output, but the impact on oil demand is marginal due to the loss of power, companies said on Wednesday.

Quake-striken Sichuan, largely a rural province that accounts for 4 percent of China's economy, is a major gas producer and user accounting for more than 20 percent of China's total, but a small oil consumer.

CNPC, parent of PetroChina (0857.HK), the dominant energy supplier in southwest China, delivered an additional 100,000 tonnes of refined oil products to Sichuan, the firm said in its in-house newspaper China Petroleum Daily.

State media has said some 60 diesel generators have been dispatched to the worst-hit regions where power has been cut.

But as only 4 gigawatts of power supply -- less than one percent of China's total power market -- was initially hit and later partially restored, industry officials said incremental demand for diesel will be small.

"Sichuan is not like the east coast. Overall demand is small and we have sufficient stocks," said a PetroChina official.

CNPC has cut its natural gas output by 5.6 million cubic metres (mcm) per day, the company newspaper said, roughly 3 percent of China's total gas market.

The top Chinese oil and gas producer said it had to reduce gas production because pressure built up in the pipeline after the quake cause a sharp reduction in outflow for consumers.

The firm has halted some drilling, shut down some refining and purification facilities in addition to gas wells in areas affected by the quake, following a government order to shut coal mines, chemical plants and oil and gas wells for safety.

Sichuan secures most of its fuel supply via the 1,240-km Lanzhou-Chengdu-Chongqing pipeline that was reopened on Tuesday after a one-day stoppage. It operates only a tiny refinery of under 20,000 barrels per day.

(Reporting by Jim Bai and Chen Aizhu) ($1=6.991 Yuan)