Riyadh :  Saudi Aramco and Abu Dhabi National Oil Co (Adnoc) are seeking deliveries of petrol and diesel to meet demand as refineries undergo maintenance, three traders with knowledge of the tenders said.

Saudi Arabia's Aramco is buying petrol from September through the end of the year, according to the traders, who asked not to be identified since the talks aren't public.

The company is also seeking diesel to fuel power plants in August and September, another trader said. Adnoc is seeking 180,000 tons of petrol, or about 50,000 barrels a day, for delivery from October 14 through mid-November in a tender closing yesterday, the traders said.

Saudi Arabia and the UAE are expanding refining capacity to process more fuels such as petrol and diesel as domestic demand rises.

Countries in the Gulf, where more than half the world's crude oil reserves are located, import fuels as they lack processing capacity at home.

Imports also help cover supply when refineries in the region undergo maintenance in cooler autumn and winter months.

Abu Dhabi is seeking petrol for delivery when Adnoc's refining division plans to conduct a month of maintenance at its main refinery at Ruwais from mid-October.

Plants including the petrol units and a condensate splitter will undergo work, people familiar with the plan said in January.

Adnoc's marketing department couldn't be reached for comment on the tender. Aramco is buying at least four cargoes of petrol a month. A cargo is usually about 250,000 barrels of petrol.

Aramco's petrol tenders indicate that some refinery units may be offline, the traders said. The company is seeking diesel as its needs more fuel to run power plants in the hot summer months as residents use more air conditioning.

Rabigh Refining and Petrochemicals Co, a joint venture between Aramco and Sumitomo Chemical of Japan, suffered a technical malfunction that cut output earlier this month.

Units suffering outages may include a hydrotreater at Aramco's joint venture refinery with Royal Dutch Shell at Jubail and a hydrocracker at the joint refinery with Exxon Mobil at Yanbu on the Red Sea, the traders said.

Aramco declined to comment on the tenders and referred questions on the refineries to the joint venture companies. Officials at the Yanbu facility didn't respond to calls or emails for comment and officials at Jubail couldn't be reached.