Middle East oil exporters are locked in an increasingly fierce battle for the world's fastest-growing markets in Asia, as producers worldwide ship more crude east to compensate for shrinking demand from the US and Europe.

The fight for the trillion-dollar Asian oil market has ended decades of comfortable dominance for Middle East producers, who faced so little competition that refiners in Asia complained of being charged a premium of a dollar or so per barrel above what buyers in Europe or the Americas paid.

The picture has changed as rising US shale supply has sapped demand in the world's largest crude consumer for the imports it previously bought from Latin America and West Africa. In Europe, years of shaky economic performance and increasing fuel efficiency have shrunk Russia's traditional market.

With nowhere else to expand, producers are pushing for more sales in Asia. The competition will become even stronger if sanctions on Iran are lifted in coming months and the million barrels per day (bpd) in Iranian exports that have been choked off returns to the market.

Under sanctions, Iran fuelled the competition by offering discounts, easy credit and free shipping to keep oil flowing. If sanctions are lifted, it may have to be even more aggressive to regain market share.

Amid these shifting market pressures, the Organization of the Petroleum Exporting Countries meets on Wednesday to consider adjusting its output target of 30 million bpd.

With oil prices well above $100 a barrel, Opec is likely to leave the target unchanged for now, say delegates who will attend the meetings in Vienna.

"These market dynamics - rising Iraqi output, increase in non-Opec production, particularly in North America, and the potential return of Iran over the longer term - are going to put downward pressure on oil futures and Opec producers will face an increasing challenge going forward," IHS oil consultant Victor Shum said.

Iran's shrinking supply has facilitated Iraq's expansion, providing Baghdad with ready made markets. Iraqi output is rising as international energy companies repair the damage wrought on its industry during years of sanctions and war.

Oil sales are paying for Iraq's reconstruction and, seeking to sell every barrel available, officials are playing hardball.

"We'll do our best to market the maximum amount of oil. We don't want to leave our available oil idle," a senior Iraqi official told Reuters, declining to be identified as he was not authorised to talk to the media. "So good luck to everybody."

Iraq will become China's second-largest supplier in 2014 if it succeeds in exporting the volume of crude it has committed to supply. Chinese firms have signed up for 882,000 bpd of Iraqi crude in 2014, up 68 per cent from 2013.

A steep cut in prices for its main export crude Basra Light helped Iraq pass Iran to become China's fifth-largest supplier in 2013. Iraq has charged buyers a discount between 40 cents and $1.10 a barrel below Saudi's Arab Medium, down from premiums to the Saudi grade a year ago, according to Reuters data.

Besides price cuts, Iraq also compensated some of its term customers for demurrage - shipping costs incurred while waiting to load crude at congested terminals, trade sources said.

Other Gulf neighbours have also ceded market share to Iraq. Baghdad wrested a supply contract for a new refinery in China away from Kuwait in early November.

Iraq should be wary of price competition, said one Kuwaiti source, since the country needed to secure money for long term development. "They may gain share in the short term but they should look at the long term," said the Kuwaiti oil source.

Kuwait has, however, been forced to cut prices itself, valuing its export crude in December at the steepest discount in nearly four years to Saudi's Arab Medium, Reuters data showed.

Kuwait may also follow Iraq and Iran's lead in offering extended credit to Indian refiners.

In the UAE, the Abu Dhabi National Oil Company has made an unprecedented move to encourage more buyers by selling cargoes with no stipulated destination for the first time in 2014.

Adnoc is also offering its customers the flexibility to load oil from the UAE's Fujairah port, which is outside the Strait of Hormuz and cheaper for shippers than sailing through the strait to the oil port of Jebel Dhanna.

High stakes

The stakes are high for exporters reliant on oil revenues to finance growing national budgets. They have to find a balance between retaining market share and steady income.

Despite more aggressive sales tactics, Opec is likely to see its market share fall. In its annual oil outlook, the group said it could lose almost 8 per cent of the market in the next five years to shale and other competing supply sources.

"The current oil price is at a level that producing countries want to maintain," said a trader with a Chinese refiner. "But the market is long so they need to fight for market share."

The flip side of the competition between Middle East exporters is that Asian refiners are benefiting from cheaper oil bills.

Iraq and Kuwait have offered to extend the payment period for crude to 60 days from 30 days. That extra month of credit could save Indian refiners, for example, close to $300,000 a day on the nearly 1 million bpd of Iraqi and Kuwait crude they buy, one Indian refining source said.-Reuters