二氧化碳驱油分层注入技术研究

摘要

CO2 for low permeability reservoir with good displacement characteristics is widely used in the secondary development of the oil field,but the general injection of CO2 will be along the di-rection of high permeability onrush,resulting in gas channeling and the reservoir cannot be effec-tively utilized.If using the method of separating injection,because of the lack of CO2 inj ectionrequired gas nozzle,it is unable to establish effective throttle pressure,failed to achieve separating gas injection.In view of the above questions,research on the development of the CO2 separating injection technology,developed a festive flow differential pressure multistage gas nozzle,the labo-ratory experiments and the field application of 29 injection wells results show that:in the flow 7 m3/d,the throttle pressure can be reached above 1 MPa by multi-stage eccentric diameter gas mouth,success rate of field application of CO2 layered injection technology was 86.2% .The re-sults of this study provide technical support for the field promotion of CO2 flooding technology.%二氧化碳对于低渗透油藏具有良好的驱替特性，在油田二次开发中被广泛应用。但是，笼统注入的二氧化碳会沿渗透率高的方向突进，造成气窜，导致油层无法有效动用。如果采用分层注入的方法，目前缺少二氧化碳注入所需的气嘴，无法建立起有效的节流压差，不能实现分层注气。针对上述问题，研究了二氧化碳驱分层注入技术，研制了一种适用于二氧化碳的大节流压差多级串联气嘴。室内试验及现场应用29口井表明：采用多级串联内孔偏心气嘴可实现流量7 m3／d时，节流压差1 MP a以上，二氧化碳分注工艺成功率高达86．2％。此研究结果为二氧化碳驱分注工艺的现场推广提供了技术保障。