Microscopic Visualization with High Resolution Optical-Fiber Scope at Steam Chamber Interface of SAGD Process

对蒸汽辅助重力排水(SAGD)过程中蒸汽室内流体流动特性进行了实验和数值模拟。实验研究使用二维缩尺油藏模型来研究蒸汽室和采油流体中的微观流体流动。利用高分辨率光纤显微镜观测了初始蒸汽室的上升和生长过程，并对蒸汽室一侧倾斜界面处的微观现象进行了可视化。在水蒸气和重油相界面上观察到了直径为0.01 mm的超细水滴。这些液滴进入稠油相，与加热的原油一起形成乳状液，然后向下流动，从生产井中开采出来。成功地证明了这些微观现象对水平方向的腔体膨胀率和采油率有一定的影响。用CMC的STARS热模拟器模拟了实验初期蒸汽室的生长过程。采用双组分(水和重油)黑油、三相(水、重油和蒸汽)和三维数值模型作为物理模型进行模拟。历史匹配的数值模拟结果与采油实验和蒸汽室形状实验结果吻合较好，采用中间3-Stone1润湿性模型表示流体行为，累积了蒸汽室界面的微观现象。此外，还试验了一种在注汽前注入表面活性剂的新工艺，即表面活性剂-SAGD工艺，以增强两井之间的连通性和产液的流动性。

Experiments and numerical simulations on fluids flow characteristics in steam chambers with the steam-assisted gravity drainage (SAGD) process were carried out. Experimental studies used two-dimensional scaled reservoir models to investigate microscopic fluids flows in the steam chamber and production fluids. The rise and growth of the initial steam chamber were observed and visualization of micro-phenomena at inclined interface on the side of the steam chamber with a high-resolution optical-fiber scope was carried out. Very fine water droplets of 0.01 mm order hi size were observed at the interface between steam and heavy oil phases. These droplets entered into heavy oil phase and created emulsion together with the heated oil, which flowed down and was produced from the production well. It was successfully demonstrated that these micro phenomena has an influence on chamber expansion rate hi horizontal direction and oil production rate.The numerical simulation of the SAGD process was also performed. The thermal simulator, CMC's STARS, was used to simulate (he experimental steam chamber growth at the initial stage. The simulation used the two-components (water and heavy oil) black oil, threephase (water, heavy oil and steam) and three-dimensional numerical model for the physical model. The results from the history-matched numerical simulation were found to be in good agreement with those of the experiments for oil production and steam chamber shape by using the Intermediate3-Stone1 wettability raodel represents fluids behavior cumulating the microscopic phenomena at the chamber interface. Furthermore, a new process named Surfactant-SAGD injecting a surfactant before starting steam injection to enhance the communication between two wells and mobility of ihe production fluids was tested.