It was meant to be a short, sharp shock. Instead, Opec members are facing a long, slow grind with no end in sight.
The deal reached with several non-Opec countries in 2016 to cut oil supply and drain excess inventories was meant to last just six months. But after last week's ugly slide into a bear market for prices, the agreement looks likely to drag into a third year as the group faces having to make further cuts in 2019.
Taking 1.8 million barrels a day of oil off the market from January 2017 was meant to drain excess inventories by the middle of that year, restore prices to an undefined "acceptable" level and balance supply and demand. Instead, the glut persisted. Although better than expected, compliance with the agreement was not complete and it was not until the deal was extended and Saudi Arabia started cutting shipments to the US in the middle of 2017 that prices really began to pick up.
But the recovery in oil prices has been a double-edged sword for Opec and friends. Sure, it has boosted revenues for most -- Venezuela and soon Iran being the exceptions -- but it has also lit a fire under US shale oil production.
The latest weekly and monthly data both show American oil output up by 2 million barrels a day year on year. That's equivalent to adding the combined production of Opec members Nigeria and Gabon in the space of 12 months. And it comes at a time when shale growth is being hampered by a lack of pipeline capacity to move crude from the Permian Basin in Texas to the refining and export facilities on the Gulf of Mexico. Those bottlenecks should ease next year, allowing supply to rise by another million barrels a day by the end of 2019, according to the Energy Information Administration. On past performance, that forecast could increase significantly.