新疆九₆区稠油油藏埋深浅、强非均质性,在蒸汽驱后期存在高含水、低油汽比、蒸汽超覆和窜流严重、波及效率和原油采收率低的问题。为进一步提高原油采收率,研究了就地凝胶体系在蒸汽驱后期的深部调驱效果。首先采用频率—弹性模量扫描、电镜扫描、热重分析法（TG-DTG）分别评价了凝胶的成胶强度、微观结构和耐温性,其次开展三维物理模拟实验研究了凝胶的调驱效果。实验结果表明：原体系中添加增稠型纤维素,凝胶弹性模量由95.6 Pa提高至316 Pa,凝胶强度大大增强;凝胶的微观网状结构更加紧密,交联更牢固,稳定性增强;当温度升至160 ℃,凝胶的质量保留率达到90 %以上,抗温能力提高。在蒸汽驱后期向高渗透层注入凝胶溶液并就地成胶后,注入压力和油汽比明显提高,含水率大幅度下降。波及系数和原油采收率分别提高了31.96 %和14.07 %。该就地凝胶能够胶结油砂,封堵高渗透层汽窜通道,有效地抑制了蒸汽汽窜和超覆。后续注入的蒸汽易进入低渗透层驱扫原油,波及效率和采收率大幅度增加,深部调驱效果显著。

Xinjiang Nine-Six reservoir is a shallow and high-heterogeneity heavy oil reservoir. In the later stage of steam flooding, there are some problems such as high water cut, low oil-steam ratio, serious overlap and channeling of steam, low sweep efficiency and low oil recovery. In order to further enhance the oil recovery, the profile control performance through the application of in-situ gel system in the late stage of steam flooding has been studied. Firstly, the gelling strength, microstructure and temperature-resistance behavior of the in-situ gel have been estimated by frequency-elastic modulus scanning, electron microscope scanning and thermogravimetry（TG-DTG） respectively. Then the 3D physical simulation experiment has been carried out to investigate the gel’s profile controlling performance. The experimental results show that after the addition of thickened cellulose in the original system, the gel’s elastic modulus increases from 96.5 Pa to 316 Pa, indicating the great increase of gel strength. The microstructure of the gel is tighter, the cross-linking is stronger and the stability has been enhanced. Weight retention rate of the gel is higher than 90 % as the temperature increases to 160 ℃, and the temperature-resistance has been improved. In the later stage of steam flooding, after injection of gel solution into high-permeability layer and its transformation into gel, the injection pressure and the oil/steam ratio increase remarkably while the water cut reduces dramatically. The sweep efficiency increases by 31.96 % and the oil recovery by 14.07 %. The in-situ gel can cement oil sand, and block the channeling path of high-permeability layer, which effectively suppresses the steam channeling and overlap. Subsequently, the injected steam can easily enter the low-permeability layer to displace crude oil, resulting in the drastically increasing of sweep efficiency and oil recovery, and indicating the remarkable profile control performance in deep parts.