Believe me with Trumps sanctions against Venezuela I am sure the US will do whatever it takes to undermine the petro project if it takes off. They are already saying that anybody who buys petros will be violating US sanctions against Venezuela
"Democratic U.S. Senator Bob Menendez and his Republican counterpart, Marco Rubio, have co-authored a letter denouncing the Petro, and requesting that the U.S. Treasury Department closely monitor its progress. The lawmakers also made suggestions on measures the agency can take to undermine the success of the digital currency"

https://www.telesurtv.net/english/news/Venezuela-Petro-Now-Accepted-as-Payment-for-Airline-Tickets-Fuel-20180302-0002.html