Although the year began with intimations of oversupply, sources say that base oil markets mostly stayed balanced during the subsequent months and into June. This may have been due to a series of scheduled and unforeseen outages at various refineries, which kept output from outracing demand.

Back in January, for example, Motiva began a turnaround that lasted into February for a catalyst change at one of the three units at its Port Arthur, Texas (total capacity: 40,300 b/d). In February, severe weather hampered operations at several refineries, driving U.S. output to its lowest point in 13 months. That month also saw Cross Oils 5,000 b/d naphthenics plant in Smackover, Ark., shut down following a small fire which sidelined it until late March.

Other plants that endured turnarounds early in the year included San Joaquin Refining in Bakersfield, Calif. (8,100 b/d), Paulsboro Refining in Paulsboro, N.J. (11,000 b/d), and Calumet at both Princeton (6,900 b/d) and Shreveport, La. (11,800 b/d). And in June the 22,000 b/d Excel Paralubes plant in Westlake, La., started a major 45-day turnaround, which lasted until early August.

The EIA data also provides a glimpse into base oil imports and exports, where the United States enjoys a positive balance of trade. The country exported a total of 13.1 million barrels in the years first half, an average of 72,000 b/d, versus a total 12.5 million barrels in first-half 2013. Viewed another way, of every 100 barrels of base oil the United States produced, 45 floated beyond its borders.

Geographically, the biggest recipients for these base oils were Mexico and Canada, which absorbed 16 percent and 11 percent of the shipments, respectively. Brazil accounted for another 10 percent, and other Latin American destinations pulled 23 percent. Sizable quantities also made their way to Europe, especially via Belgium, and to Singapore.

By contrast, foreign product had a tougher time getting a foothold in the U.S. market. Base oil imports fell to 5.1 million barrels in the first six months, versus 6.4 million barrels in first half 2013. Thats a 20 percent decline.

Imports from one of the countrys largest base oil trading partners, South Korea, suffered quite a bit in the first six months of this year and reached just 1.52 million barrels, a 30 percent drop from the prior-year period. South Korea did manage narrowly to edge out Canada, which sent 1.47 million barrels into the United States from January to June.

An even larger decline was seen in volumes coming from Qatar, which in first-half 2013 sent 1.4 million barrels to the United States. Through June of this year, Qatar supplied only 0.9 million barrels to the United States.

Besides the wobbling volumes from South Korea and Qatar, what else might be behind the decline in first-half imports? For one thing, U.S. refined products continued to hold a cost advantage, so there was no or little opportunity for arbitrage from Asia and Europe.

Second, supply was said to be fairly tight in Asia during the first quarter, so refiners in that region were not in a great position to export, sources remarked. As the summer waned, availability began to ease to the point where the Asian market is actually said to now be oversupplied.

Price reporter Gabriela Wheeler offers updates on Asias base oil markets every week at www.LubeReportAsia.com, our sister publication.