Wen Yuchen, Hou Jirui
Key Laboratory of Petroleum Engineering, Research Institute of Unconventional Petroleum Science and Technology, China University of Petroleum (Beijing), Beijing 102249, China.
Gels. 2023 Sep 6;9(9):722. doi: 10.3390/gels9090722.
Gas flooding and foam flooding are potential technologies for tertiary oil recovery in fractured-vuggy reservoirs. The development and mechanism research of fractured-vuggy reservoirs is difficult due to the complex structures and the strong heterogeneity of fractured-vuggy reservoirs. Visualization simulation is one of the effective methods to study the flow behavior of fluid in fractured-vuggy reservoirs. In this study, an upscaling method of visualization simulation from one dimension (1D) to three dimensions (3D) was established, and the physical models of fractured-vuggy reservoirs were designed and fabricated. Water flooding, gas flooding, and gel foam flooding were carried out in the models. The experimental results showed that gas flooding has a single flow channel and water flooding has multiple flow channels in fractures and vugs. Gel foam with an excellent capability of mobility control and a high microscopic displacement efficiency swept in all directions at a uniform velocity. The EOR mechanisms of gel foam in fractured-vuggy reservoirs were mainly as follows: reducing interfacial tension, increasing mobility ratio, selectively plugging high permeability channels, and discontinuous flow. In the displacement process of fractured-vuggy reservoirs, water should be injected from the well at the bottom of the reservoir, and gas should be injected from the well located in the vug at the high part of the reservoir. Gel foam with strong stability and high viscosity should be selected and injected in most kinds of injection wells in fractured-vuggy reservoirs. This study provides a complete method of visualization simulation for the study of flow behavior in fractured-vuggy reservoirs and provides theoretical support for the application of gas flooding and gel foam flooding in fractured-vuggy reservoirs.
气驱和泡沫驱是缝洞型油藏三次采油的潜在技术。由于缝洞型油藏结构复杂且非均质性强，其开发和机理研究具有一定难度。可视化模拟是研究缝洞型油藏中流体流动行为的有效方法之一。本研究建立了一种从一维（1D）到三维（3D）的可视化模拟尺度升级方法，并设计制作了缝洞型油藏物理模型。在模型中开展了水驱、气驱和凝胶泡沫驱实验。实验结果表明，气驱在裂缝和孔洞中有单一流动通道，水驱有多个流动通道。具有优异流度控制能力和高微观驱替效率的凝胶泡沫以均匀速度向各个方向驱替。凝胶泡沫在缝洞型油藏中的提高采收率机理主要如下：降低界面张力、提高流度比、选择性封堵高渗透通道以及不连续流动。在缝洞型油藏的驱替过程中，应从油藏底部的井注水，从位于油藏高处孔洞中的井注气。应选择稳定性强、粘度高的凝胶泡沫并注入缝洞型油藏的大多数注入井中。本研究为缝洞型油藏流动行为研究提供了完整的可视化模拟方法，为气驱和凝胶泡沫驱在缝洞型油藏中的应用提供了理论支持。
