BTW, PSX has a JV with Vz to process Merey (heavy, sour crude) from Vz.
They also have a refinery that runs crudes from Vz that VLO can even hardly touch.
Several PSX refienries (under different badges then) were pioneers in running sour crude.
BTW, sour crude is NOT where the margins really are right now. Look at the price of Maya vs. other crudes and then cnsider the higher 'costs' to process it. Also look at Mars and Arab Medium. On the GC (where VLO is concentrated) there are other crudes with better margins (genearlly, since each refinery is unique.)
Fore...I think you are missing the point on the Venezuela shut down. Valero and other Gulf Coast refineries do a ton of exports to Latin America and South America. Venuezuela will not be able to produce engough fuel for domestic business and?or any exports they do. Refining is a global business and the Gulf Coast is not far from Venezuela. Also, according to Valero, although VZ exports of refined products to the US were upwards of 350,000 barrels of day 7 years ago, they still ship about 50,000 to 60,000 barrels a day to the US.
Also, if the heavy sour crude discount is $8 or more, which it is now, it is indeed more profitable for Valero to run sour/heavy crudes.