NUMERICAL SIMULATION STUDY ON ENHANCING RECOVERY FACTOR BY CO_2 DISPLACEMENT

Huge number of greenhouse gas emission of carbon dioxide(CO2),which leads to global warming,is accelerating the rising temperature and the climate change on the Earth.Global warming has put much pressure on both human being's survival and social economy's development.The most effective way of disposing CO2 is to inject them directly into oil and gas fields,and only in this way not only CO2 can be sealed up for keeping but the recovery factor of oil and gas fields can be enhanced.Aiming at this issue,CO2 was injected into a certain oilfield to carry on water alternating gas displacement by adopting Eclipse software to accomplish correlation study through numerical simulation on six different sets of developing adjustment schemes.This study shows that this method can help improve recovery factor by 5%-10%,equivalent to 2 billion of US dollars,and meanwhile the total CO2 stored in geological way reaches up to 550 thousand tons,having the same quantity of annual greenhouse gas emission from a big city with 5 million people,which also proves its great significance in environment protection.This case of study also shows water alternating gas displacement in horizontal wells is the best way for both storing CO2 in geological way and enhancing recovery factor of oil and gas fields.This method has been proved to have both the maximum accumulative oil production and the greatest number of gathered CO2.This result provides technical reference for the tertiary oil production in other similar oil fields,and the foundation for China's enforcing the obligation of CO2 emission cuts by the Kyoto Protocol in 2012.