氮气辅助SAGD开采技术优化研究

利用物理模拟及数值模拟方法，研究了在蒸汽辅助重力泄油（SAGD）过程中添加氮气提高顶水超稠油油藏开发效果的生产机理，主要包括：形成隔热层，降低热损失，提高热效率；维持系统压力，改善流度比；降低原油黏度，提高流动能力。优选出了氮气注入方式、氮气与蒸汽比和氮气总注入量。研究结果表明，氮气辅助SAGD开采技术在杜84块馆陶油层开采中是可行的，有利于蒸汽腔的侧向扩展，增加蒸汽的横向波及体积；在SAGD过程中添加氮气能够有效控制顶水下泄，延长SAGD生产时间3～4年，提高了油藏采收率和油汽比。

Optimization of N2 injection technology during steam assisted gravity drainage process

The physical simulation and numerical modeling were used to study the production mechanism of adding N₂ during steam assisted gravity drainage (SAGD) process in super heavy oil reservoir with top water. These mechanisms mainly include forming insulation layer to reduce heat loss and increase heat efficiency, maintaining reservoir pressure, and reducing oil viscosity to improve mobility. The N₂ injection method, N₂-to-steam ratio and N₂ injection volume were optimized. The application results of the N₂ injection technology in Guantao reservoir of Du 84 block showed that the N₂ injection technology during SAGD process was feasible and beneficial for expansion of steam chamber in sideways and increase of the horizontal sweep volume. N₂ injection during SAGD process could effectively control the down flow of top water and lengthen SAGD production time by 3-4 years. Both the reservoir recovery factor and oil steam ratio could be improved.