The Organisation of the Petroleum Exporting Countries, which previously decided against reducing supply to compete with higher-cost rivals, has revised its global supply forecasts for tight oil, including shale, in its 2015 World Oil Outlook. OPEC stated that demand for its crude will be 30.70 million barrels per day (bpd) in 2020, slightly lower than the 30.90 million bpd expected for next year. Despite a significant decrease in oil prices, the organization anticipates producing about 1 million bpd more than the expected demand in 2020. Oil prices have plummeted by more than half in the past 18 months, hitting an 11-year low of $36.04 per barrel this week. Despite the drop in prices, OPEC believes that the demand boost resulting from low crude prices will diminish over time. In the foreword to the report, OPEC Secretary-General Abdullah al-Badri discussed the visible impact of the recent oil price decline on demand, particularly in the short term followed by a decrease in the medium term. OPEC members are divided on the effectiveness of the market-share strategy implemented in 2014, with disagreements leading to the failure to set a production ceiling at a recent meeting. Despite this, the report indicates an improved medium-term outlook for OPEC as a major oil supplier, with a projected increase in demand for OPEC crude by 2020 compared to previous expectations. OPEC has stopped working on updating its report in the middle of the year, but has since revised its forecast for 2016 non-OPEC supply to show a decline. The report does not include Indonesia, which re-entered in December. The main figures indicating OPEC's market share being under pressure have remained the same as in a previous confidential report obtained by Reuters in November. Initially, OPEC underestimated the impact of shale oil, but in 2012 acknowledged for the first time that it could have a significant effect. The years of high prices, supported by OPEC's past policy of reducing supply, have made non-conventional oil like shale economically viable. In contrast to previous reports, OPEC now states that many projects can be profitable at lower prices. The report indicates that certain areas within some plays can break even at prices lower than those seen in 2015, leading to anticipated production growth. Global tight oil production is projected to increase to 5.19 million bpd by 2020, peak at 5.61 million bpd in 2030, and then decrease to 5.18 million bpd by 2040. Argentina and Russia are expected to become significant producers alongside North America. Last year's estimates were lower, predicting 4.50 million bpd by 2020 and 4 million bpd by 2040. In a more optimistic scenario, tight oil production could expand to Mexico and China, potentially reaching nearly 8 million bpd by 2040 according to OPEC. As recently as 2013, OPEC believed that tight oil would only affect North America. The report suggests that OPEC's market share will increase in the future due to declining rival supply growth. It is projected that OPEC's crude demand will reach 40.70 million bpd in 2040, accounting for 37 percent of global supply, up from 33 percent in 2015. OPEC has slightly raised its short-term forecast for global oil demand, anticipating a rise to 97.40 million bpd by 2020, an increase of 500,000 bpd from the previous year. However, factors such as slower economic growth, the minimal impact of crude costs on pump prices, and the depreciation of some currencies against the dollar will limit the response to lower crude prices, according to OPEC. OPEC predicts that by 2040, demand will reach 109.80 million bpd, which is 1.3 million bpd lower than the previous year due to energy efficiency and climate-change mitigation efforts. It is expected that there will only be a slight increase in oil prices. The report assumes that OPEC's basket of crude oils was $55 in 2015 and will increase by $5 annually to reach $80 by 2020.