Saudi Arabia maintained crude oil shipments to the United States in June near their highest level since 2008, data showed, despite a serious glitch that has crippled its newly expanded joint-venture refinery in Texas.

In the four weeks to June 29, the United States imported an estimated 1.44 million barrels per day (bpd) of Saudi crude, according to calculations based on preliminary Energy Information Administration (EIA) data. That was steady with the 1.45 million bpd imported in the first four months of the year.

The data runs counter to expectations that the one-third surge in Saudi shipments to the United States this year would abruptly slow after Motiva Enterprises shut its new crude unit (CDU) at the Port Arthur, Texas, refinery for up to a year after an apparent chemical leak corroded key pipes.

Instead, it suggests that state oil firm Saudi Aramco either found new customers to buy crude that had been earmarked for the idled 325,000 bpd unit or pumped it into storage tanks at the plant, which has been running at less than half its full capacity since early June.

However, because shipping schedules are set weeks or even months in advance, it may have been too late to redirect or resell some June cargoes, delaying the decline until July. An industry source said two weeks ago that state oil firm Saudi Aramco had halted deliveries until at least the middle of July.

"The Motiva problems emerged suddenly and couldn't stop the delivery of significant volume of crude oil into the system all at once," said Ed Morse, global head of commodities research at Citigroup and a former energy expert at the State Department.

"It wouldn't be surprising to see deliveries from the Kingdom to the U.S. starting to fall off in either next week's data or the data from the week after that."

Motiva, co-owned by Royal Dutch Shell, has said the unit suffered corrosion and could be closed for months of repairs - sources say they have told workers these could take up to a year. The unit is at the heart of a $10 billion expansion that made Port Arthur the biggest refinery in the United States.

The weekly EIA figures do show that imports fell to just 1 million bpd in the week to June 22, although that was a period when Tropical Storm Debby shut the country's biggest import terminal. They rebounded to more than 1.5 million bpd in the most recent week, according to data on Thursday.

Separate data from the EIA showed that Saudi crude oil shipments bound specifically for Motiva's Port Arthur refinery surged in April to nearly 375,000 bpd, up from a first-quarter average of 206,000 bpd as the company began to heat up the crude unit for operation.

The extra crude bound for that plant accounted for almost the entire rise in Saudi imports in April, which reached nearly 1.6 million bpd, the highest monthly total since July 2008. First-quarter imports averaged around 1.4 million bpd.