Crude, like most commodities .. and in many instances even more so, is a fungible commodity. A barrel of crude, assuming the same sulphur content, etc., is a barrel of crude. If imported crude can be transported to refining facilities (which the US is woefully short of) from a harbor point, for less than from tanks in West Texas, it is simply a matter of go with the cheapest transportation.

No biggie. Production v use ... whether you sell for export or domestic use, it's all the same balance sheet.