Nigeria’s new Dangote mega-refinery is lapping up ever more US crude, bringing the barrels thousands of miles across the Atlantic ocean.

Dangote bought more than 16 million barrels of West Texas Intermediate crude oil so far this year, data compiled by Bloomberg show. In August and September, the proportion it will take from the US — as opposed to Nigerian barrels — may be set to rise, based on tenders for new supply seen by Bloomberg.

For Nigeria and Dangote, the use of US crude likely reflects where there are spare barrels available to buy in the world and the most competitive price. The refinery has been billed as a way of helping Nigeria wean itself off foreign fuel supplies.

The refinery near Lagos mostly runs on local crude supplies that can reach the plant from offshore terminals in as little as a couple of days. It took in more than 41 million barrels of feedstock in the first half of the year as it completed test runs and gradually increased processing rates, tanker-tracking data show. Of that, about a quarter has been American supply.

Inflows of American feedstock could be about to increase significantly. In the past week, Dangote purchased 5 million barrels of WTI Midland for delivery next month and in September. The company also started a tender process in which it’s looking to buy a further 6 million barrels of American crude for September. 

Nigeria competes with rival suppliers like the North Sea, Mediterranean and North Africa for crude sales in Europe and Asia.