London: Opec oil exports, excluding Angola, will leap 610,000 barrels per day (bpd) in the four weeks to September 8, with most heading west to replenish falling US stocks, an analyst who estimates future shipments said on Thursday.

Roy Mason of consultancy Oil Movements estimated Opec seaborne exports would rise to 24.20 million bpd, compared with 23.82 million bpd in the four weeks to August 11.

The jump was the biggest this year, taking crude shipments, or exports, to the highest level since April.

Mason said some 400,000 bpd were heading to Western refiners with the balance flowing to Asia.

He said the jump in Opec supply was dramatic in the period analysed because his estimate was comparing exports that hit their lowest point for the year in early August, before turning higher again.

Shipments have been falling steadily since mid-April, a pattern corroborated by long-haul VLCC freight rates from the Gulf and West Africa which have struck four-year lows to the United States in the past month, he said.

VLCC rates have only just begun recovering from those lows, reflecting a rise in shipments of OPEC oil.

Analysts from Lloyd's Marine Intelligence Units (LMIU) APEX division broadly agreed that OPEC exports had slipped from a higher supply average in April-May because of ebbing demand from Western refiners, before rising again.

Charter bookings

LMIU tracks shipments covering more than 90 per cent of the world's tanker fleet including spot, term and oil company owned and managed vessels.

Mason estimates Opec supply through spot charter bookings, which represent about 50 per cent of all oil tanker supply shipments.

"There's been a big draw down on US bound stocks, on the water and on land, because of the gasoline season...but oil in transit is going to go up from here on. That's for sure," he said.

Crude stocks rose 1.9 million barrels in the week to August 17, the EIA said on Wednesday in a surprise build. Stocks had fallen five straight weeks before that.

"The latest estimate means demand is going up in the Western hemisphere, it is picking up seasonally. From the Opec producer point of view the figures show Opec are operating within the same parameters as they have been right the way through the year, give or take a few hundred thousand barrels," Mason said.

He estimated Opec was adhering to about 840,000 bpd of the pledged 1.7 million cut since November 1 last year.

OPEC decided last year to lower output by 1.7 million bpd in two stages starting November 1, 2006, and February 1 this year. The reduction includes 10 countries, all except Iraq and new member Angola.

Cut in output

The group met about 900,000 bpd of the promised cutback in July, according to a Reuters survey.

Oil hit a record high of $78.77 a barrel on August 1, but financial market turmoil caused by the US mortgage sector problems has pushed it lower.

The mortgage crisis has spread to other markets in recent weeks and oil has been hit as investors, fearing a credit squeeze, have sold to raise cash.