You quoted my post linking to an article.
This is directly from that article:
That drop in crude prices had been triggered by an oil price war between Saudi Arabia and Russia after Moscow rejected a proposal by OPEC to cut 1.5 million barrels of production per day.
The sharp decline in oil prices spurred giant capex and job cuts across the U.S. shale industry, which has some of the highest production costs in the world.
The article went on to give Trump credit for negotiating an end to that, and bringing balance back to oil markets. Where did you get lost?