Answer: They want to make sure that there is a steady supply at a reasonable price so they can use the oil that they need.
Explanation:
As a cartel, the OPEC+ member countries collectively agree on how much oil to produce, which directly impacts the ready supply of crude oil in the global market at any given time. OPEC+ subsequently exerts considerable influence over the global market price of oil and, understandably, tends to keep it relatively high in order to maximize profitability.
If OPEC+ countries are unsatisfied with the price of oil, it is in their interests to cut the supply of oil so prices rise. However, no individual country actually wants to reduce supply, as this would mean reduced revenues. Ideally, they want the price of oil to rise while they increase supply so that revenues also rise. But that is not market dynamics. A pledge by OPEC+ to cut supply causes an immediate spike in the price of oil. Over time, the price reverts back to a level, usually lower, when supply is not meaningfully cut or demand adjusts.
Conversely, OPEC+ can decide to boost supply. For instance, on June 22, 2018, the cartel met in Vienna and announced that they would be increasing supply.3 A big reason for this was to offset the extremely low output by fellow OPEC+ member Venezuela.
Saudi Arabia and Russia, two of the largest oil exporters in the world who both have the ability to increase production, are big proponents of increasing supply as that would increase their revenues. However, other nations, who cannot ramp up production, either because they are operating at full capacity or are otherwise not allowed to, would be opposed to this.
