* Sept crude buying rises for third month, to 4-month high
* Refiners say they are concerned about high crude oil prices
* Gas imports drop from August (Adds analyst comment)
BEIJING, Oct 12 (Reuters) - China's daily crude oil imports in September hit their highest level since May, customs data showed on Friday, as independent refiners looked to shore up their inventory ahead of winter.
Shipments into the country last month stood at 37.12 million tonnes, or 9.05 million barrels per day (bpd), up from 9.04 million bpd in August and marking their third straight monthly rise, according to numbers from the General Administration of Customs.
Total crude imports over the first nine months of the year climbed 6 percent from the same period in 2017 to 336 million tonnes, or 8.98 million bpd, the customs data showed.
"Crude run rates have been rising since September. With stable fuel demand, we have been scooping up crude oil, pushing up premiums of some crude grades," a crude trader with an independent refinery said before the data was released. He declined to be identified as he was not authorized to speak with media.
However, some Chinese refiners said they were concerned that a rally in global oil prices would erode their profit margins.
"Crude import growth slowed in September (partly) due to what was probably positive growth in domestic crude production," said Sengyick Tee, a Beijing-based consultant at SIA Energy.
International benchmark Brent crude oil futures stood around $80.60 per barrel on Friday, up more than 20 percent from the beginning of the year.
Looking ahead, China has hiked non-state oil import quotas for 2019, potentially supporting imports of the commodity.
Total natural gas imports in September came in at 7.62 million tonnes, the customs data showed, dropping from 7.76 million tonnes in August. Imports over the first 9 months of 2018 stood at 64.78 million tonnes, a year-on-year increase of 34 percent.
For more details, click on TRADE/CN (Reporting by Meng Meng and Aizhu Chen Editing by Joseph Radford)