Does this refinery company have its own oil well production or does it have to buy crude?
I believe they are part owners in three offshore platforms but they are primarily a US refining and distribution (retail) company.
2007 Annual Report
http://www.valero.com/NR/rdonlyres/D105445B-CC29-413C-99B5-C768FDF6E151/0/VLOARFINALFORWEB.pdf
See Page 17