Abstract: Tight oil in Fuyu reservoir is an important alternative resource to ensure the sustainable development of Daqing oilfield, mainly distributed in Fuyu reservoirs in Changyuan, Sanzhao and Qijia-Gulong areas of Daqing. Boasting of high development potential, it is the reserve base for continuous and stable production of Changyuan peripheral oilfield. Through nearly 10 years of technical research and field tests, an effective development technology has been established. However, in terms of development efficiency, the horizontal well volume fracturing elastic exploitation is characterized with short high production period and fast decrease in production as a whole; the initial monthly decreasing rate is 20%~30%, and the annual decreasing rate is 40%~60%; after 2~3 years of elastic exploitation, the production wells encounter the difficulty in maintaining production under saturation pressure, and the elastic recovery rate is only 5.7%~8.2%. In order to improve the recovery rate of tight oil horizontal well development, indoor stress-sensitive physical simulation experiments and numerical simulation are carried out to determine the best time for energy replenishment, i.e., when the formation pressure coefficient is 0.60~0.65; CO₂ huff-puff is selected as the preferred recovery enhancement method; the injection volume is optimized to be 7 000~9 000 t/km, injection pressure to be 12~13 MPa, injection rate to be 130~150 t/d, and soaking time to be 40~50 d for the kilometer horizontal well section. The recovery enhancement in the single horizontal well field test ranges from 1.44% to 3.33%, with an average of 2.44% and an input-output ratio of 1:1.63 (oil price of $60), showing good technical and economic efficiency.

Key words: Songliao Basin, tight oil, horizontal well, CO₂ huff-puff, field test, development practice

摘要： 扶余油层致密油是保障大庆油田可持续发展的重要接替资源，主要分布在大庆长垣、三肇和齐家—古龙地区的扶余油层，开发潜力大，是长垣外围油田持续稳产的储量基础。通过近10年的技术攻关和现场试验，已经形成有效的开发技术系列。但从开发效果来看，水平井体积压裂弹性开采整体上具有高产期短、产量递减快的生产特点，初期月递减率为20%~30%、年递减率为40%~60%；弹性开采2~3 a后，生产井表现出难以保持饱和压力生产的特点，弹性采收率仅为5.7%~8.2%。为提高致密油水平井开发的采收率，开展了核磁共振、岩心物理模拟、岩心驱替、应力敏感等实验和数值模拟研究，确定了最佳能量补充时机的地层压力系数为0.60~0.65，优选CO₂吞吐为首选提高采收率开采方式，优化水平井段注入量为7 000~9 000 t/km、注入压力为12~13 MPa、注入速度为130~150 t/d、焖井时间为40~50 d。经水平井现场试验，单井阶段提高采收率为1.44%~3.33%、平均为2.44%，在60美元油价下投入产出比为1∶1.63，技术经济性较好。

关键词: 松辽盆地, 致密油, 水平井, 二氧化碳吞吐, 现场试验, 开发实践