from my understanding of the development of the international oil trade in the 20th century, one of the key advancements by multinational oil in the West was to learn lessons from the British, and do two important things on foreign soil: always back a leader that can hold on with local support; always pay the Nationalist/Military oil interests very well, in addition to making trade rights built-in.

Unfortunately, it seems that the "wild west" behavior of the USA in South America, in the wake of the brutal Spanish conquest long ago, made some enemies (that have oil) that are not easy to talk to now.