U.S. commercial crude oil stocks rose 3.52 million barrels to 397.66 million barrels during the reporting week ended April 18, U.S. Energy Information Administration (EIA) oil data showed this week.

The build was in line with analysts' expectations. Analysts polled Monday had been looking for a 3.1 million-barrel build.

The bulk of the build was concentrated in the U.S. Gulf Coast (USGC) region, where stocks rose 2.44 million barrels to set yet another record high of 209.61 million barrels.

This build puts USGC crude oil stocks just over 13% above the five-year average of EIA data.

Amid a modest increase in imports -- up just 16,000 barrels per day (b/d) to 3.83 million b/d -- the build was tempered by sharply higher crude oil runs at USGC refineries.

USGC runs rallied 372,000 b/d to 8.51 million b/d – the highest since the 8.55 million b/d for the week ended December 27. This helped to push USGC utilization rates 4.2 percentage points higher to 94.1% of capacity.

The gains suggest the region has largely exited spring maintenance.

Total U.S. refinery utilization rates rose 2.2 percentage points to 91% of capacity. Analysts had been looking for this to remain flat.

Meanwhile, utilization rates on the U.S. Atlantic Coast (USAC) rose 5.4 percentage points to 84.6% of capacity amid a 71,000 b/d surge in crude oil runs.

However, this barely made a dent in crude oil stocks, which rallied 2.24 million barrels to 14.05 million barrels. This is likely attributable to a 296,000 b/d jump in imports, which rose to 878,000 b/d.

This comes in somewhat below the 409,000 b/d increase shown in American Petroleum Institute (API) data released late Tuesday. However, the increase is notable considering that refiners in the region had been backing out imports in favor of Bakken crude oil railed in from North Dakota.

USAC imports hit an all-time low of 422,000 b/d during the reporting week ended November 15, 2013. According to the EIA's data, the last time USAC imports topped 1 million b/d was in September 2013.

The jump in imports could be a one-off event or could be related to the recent tightening of the Brent-WTI spread, which helped push the cost of delivered Bakken to the USAC above the delivered cost of some North Sea and West African crude oils.

The front-month, May, Brent-WTI spread narrowed to a near seven-month low of $3.27 per barrel on April 14.

Imports from Nigeria, many of which traditionally head to the USAC, rose 115,000 b/d the week ended April 18 to 219,000 b/d. This is the highest Nigerian imports have been since late October. Angolan imports also rose, up 67,000 b/d to 117,000 b/d.

U.S. Midwest crude oil stocks fell 1.73 million barrels to 95.62 million barrels, EIA data showed. Of that, stocks at New York Mercantile Exchange (NYMEX) delivery hub Cushing, Oklahoma, fell 788,000 barrels to 26.04 million barrels. This puts Cushing stocks almost 34% below their five-year average.

U.S. GASOLINE STOCKS DRAW

U.S. gasoline stocks fell 274,000 barrels to just over 210 million barrels the week ended April 18, putting them 2.5% below the five-year average.

Analysts had been looking for a 1.7 million-barrel draw.

Stocks on the USAC -- home to the New York Harbor-delivered NYMEX RBOB contract -- fell 99,000 barrels to 54.06 million barrels.

Gasoline production fell 48,000 b/d to 8.89 million b/d, while implied demand* for the fuel dropped 186,000 b/d to 8.43 million b/d.

Imports to the USAC came off slightly, down 63,000 b/d to 402,000 b/d.

U.S. distillate stocks rose 597,000 barrels to 112.51 million barrels the week ended April 18, counter to analysts' expectations of a 900,000-barrel draw.

Implied demand dropped 331,000 b/d to 3.83 million b/d, while production rose 100,000 b/d to 4.98 million b/d.

USGC ultra-low sulfur diesel stocks, meanwhile, rose 1.36 million barrels to 30.84 million barrels.

* Implied demand is the amount of product that moves through the U.S. distribution system, not actual end consumption.