Guessing Game: What Are OPEC Nations Thinking? OPEC produces one-third of the world's oil and ? in theory, at least ? can affect global oil prices depending on how much oil it decides to sell. In reality, OPEC member countries have different, often conflicting priorities and don't adhere to the cartel's official targets for production. When the cartel meets Thursday in Vienna, Iran and Venezuela are expected to call for a production cut in an effort to boost prices. Saudi Arabia, by far OPEC's biggest producer and most influential member, along with some of its allies, appear willing to have prices drift lower for now. Trying to guess what OPEC members are thinking, and how the cartel will act, is a high stakes parlor game in the oil industry. Here are some theories experts are raising: Saudi Arabia and other relatively well-off OPEC countries, such as the United Arab Emirates and Kuwait, want to let prices fall to slow or stop production growth in the U.S. and Canada, where drillers require higher prices to make money. That way, OPEC can increase its market share. Saudi Arabia and its allies want to force prices lower to increase pressure on fellow OPEC member Iran during international negotiations over its nuclear program. Saudi Arabia does not want Iran to have a nuclear weapon. If prices stay low, Iran's economy suffers and its leaders could be more willing to limit its nuclear development in exchange for a relaxation of sanctions. Saudi Arabia wants to punish Russia for its support of Iran's nuclear program. Russia is not an OPEC member but is among the world's top three producers. It needs high oil prices to fund its government. Venezuela, Iran and Iraq ? countries in difficult financial shape ? want OPEC to cut production quickly and sharply to force prices higher. They are unlikely, however, to offer to cut their own production. Saudi Arabia increased its production in recent years to help replace supplies lost out of Iran, Syria and elsewhere. Many OPEC members feel Saudi Arabia should therefore be the country to cut now. Saudi Arabia wants to keep oil flowing and prices low because it fears that the battle to defeat the Islamic State group will at some point disrupt oil supplies or infrastructure in Syria and possibly Iraq. If oil prices start from a lower point, the global economy would be better able to absorb a price spike if those oil supplies are disrupted. Saudi Arabia sees no need to tamper with what it says is the normal oil cycle. A period of high prices inspired drillers to develop new oil projects around the world. They were successful, so supplies rose and prices fell. Investment will now slow, supply will tail off, and prices will naturally rise again in the coming years.