Two Chevron Corp. employees detained in Venezuela last week could be charged with treason for refusing to sign a parts contract for a joint venture with state-owned oil company PDVSA, according to two sources familiar with draft charges against the U.S. firm’s executives. The arrests, by national intelligence agents, marked the first at a Western oil firm in Venezuela and represent a dramatic escalation of growing tensions between PDVSA and foreign companies over control of supply contracts, the sources told Reuters. The widening dispute could worsen operational chaos that has caused the OPEC nation’s oil output to plunge by 23 percent, or 450,000 barrels per day, since October. “These detentions are going to accelerate the operational crisis,” another source with knowledge of Chevron’s operations told Reuters. “Procurement could end up in paralysis if nobody wants to take the risk of signing or authorizing anything.” The draft treason charges – seen …