The Organization of Petroleum Exporting Countries will increase shipments through late October as refiners in China resume operations after seasonal maintenance, according to tanker tracker Oil Movements.

OPEC, which supplies about 40 percent of the world’s oil, will raise exports by 100,000 barrels a day, or 0.4 percent, to 23.97 million a day in the four weeks to Oct. 19 compared with 23.87 million a day in the period to Sept. 21, the researcher said in a report. The figures exclude two of OPEC’s 12 members, Angola and Ecuador.

“Chinese refiners are pulling out of maintenance so their demand is climbing up,” Roy Mason, the company’s founder, said by phone from Halifax, England. “The West is in maintenance, and refiners there are in deep trouble, as crude demand in the West is plummeting.”

Refiners boost operating rates in the fourth quarter to meet higher demand for heating fuel during the Northern Hemisphere winter. Brent crude was at $109.21 a barrel as of 4:13 p.m. today on the ICE Futures Europe exchange in London, having advanced 6.1 percent in the third quarter.

Middle Eastern shipments will climb 0.6 percent to 17.61 million barrels a day to Oct. 19, compared with 17.51 million in the month to Sept. 21, according to Oil Movements. Those figures include non-OPEC nations Oman and Yemen.

Crude on board tankers will increase 2.3 percent to 487.28 million barrels on Oct. 19, data from Oil Movements show. The researcher calculates volumes by tallying tanker bookings, and excludes crude held on vessels for storage.

OPEC’s members are Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates and Venezuela. It will next meet in Vienna on Dec. 4.