Even without Chavez' foolishness, Venezuelan output is in decline. Aging fields. Their light sweet crude is less, as it is worldwide. Estimates are that LSC is some 20% to 25% of world oil production. (Which is why Valero is a better buy than other oil stocks; they're already set up for refining sour crude.)
Venezuela's skilled people started bailing out when Chavez first took over, which is why they're already in deep economic doo-doo. Anybody who could get their capital out has already done so.
Yeah, China has been negotiating to buy from Venezuela, just as from Canada's tar sands. I don't know anything about Chinese refining systems.
In USD and at US labor rates, a refinery to produce 200,000 bbl/day of gasoline is a billion bucks and three years construction time. FWIW. No idea of % labor & % material.