SAN RAMON (CBS SF / CNN) — Chevron’s nearly century-long relationship with Venezuela might not survive the Maduro regime’s fight with the United States. Not only is Venezuela’s infrastructure crumbling, but the OPEC member’s national oil company has been sanctioned by the Trump administration. Chevron, based in San Ramon and the last major US oil company still operating in Venezuela, could be forced to leave unless US officials extend sanctions waivers scheduled to expire on July 27. A Chevron exit would follow on the heels of other major American companies that have retreated from the chaos in Venezuela in recent...