Alcorn Zachary Paul, Føyen Tore, Gauteplass Jarand, Benali Benyamine, Soyke Aleksandra, Fernø Martin
Department of Physics and Technology, University of Bergen, 5007 Bergen, Norway.
SINTEF Industry, 7034 Trondheim, Norway.
Nanomaterials (Basel). 2020 Sep 25;10(10):1917. doi: 10.3390/nano10101917.
Nanoparticles have gained attention for increasing the stability of surfactant-based foams during CO foam-enhanced oil recovery (EOR) and CO storage. However, the behavior and displacement mechanisms of hybrid nanoparticle-surfactant foam formulations at reservoir conditions are not well understood. This work presents a pore- to core-scale characterization of hybrid nanoparticle-surfactant foaming solutions for CO EOR and the associated CO storage. The primary objective was to identify the dominant foam generation mechanisms and determine the role of nanoparticles for stabilizing CO foam and reducing CO mobility. In addition, we shed light on the influence of oil on foam generation and stability. We present pore- and core-scale experimental results, in the absence and presence of oil, comparing the hybrid foaming solution to foam stabilized by only surfactants or nanoparticles. Snap-off was identified as the primary foam generation mechanism in high-pressure micromodels with secondary foam generation by leave behind. During continuous CO injection, gas channels developed through the foam and the texture coarsened. In the absence of oil, including nanoparticles in the surfactant-laden foaming solutions did not result in a more stable foam or clearly affect the apparent viscosity of the foam. Foaming solutions containing only nanoparticles generated little to no foam, highlighting the dominance of surfactant as the main foam generator. In addition, foam generation and strength were not sensitive to nanoparticle concentration when used together with the selected surfactant. In experiments with oil at miscible conditions, foam was readily generated using all the tested foaming solutions. Core-scale foam-apparent viscosities with oil were nearly three times as high as experiments without oil present due to the development of stable oil/water emulsions and their combined effect with foam for reducing CO mobility.
在二氧化碳泡沫强化采油（EOR）和二氧化碳储存过程中，纳米颗粒因能提高基于表面活性剂的泡沫稳定性而受到关注。然而，在储层条件下，纳米颗粒 - 表面活性剂混合泡沫配方的行为和驱替机制尚未得到充分理解。这项工作对用于二氧化碳EOR及相关二氧化碳储存的纳米颗粒 - 表面活性剂混合发泡溶液进行了从孔隙尺度到岩心尺度的表征。主要目标是确定主要的泡沫生成机制，并确定纳米颗粒在稳定二氧化碳泡沫和降低二氧化碳流动性方面的作用。此外，我们还揭示了油对泡沫生成和稳定性的影响。我们展示了在有无油存在的情况下，孔隙尺度和岩心尺度的实验结果，将混合发泡溶液与仅由表面活性剂或纳米颗粒稳定的泡沫进行了比较。在高压微模型中，颈缩被确定为主要的泡沫生成机制，其次要机制是遗留产生的二次泡沫。在连续注入二氧化碳期间，气体通道穿过泡沫形成，且结构变粗。在没有油的情况下，在含表面活性剂的发泡溶液中加入纳米颗粒并不会产生更稳定的泡沫，也没有明显影响泡沫的表观粘度。仅含纳米颗粒的发泡溶液几乎不产生泡沫，这突出了表面活性剂作为主要泡沫产生剂的主导地位。此外，当与选定的表面活性剂一起使用时，泡沫的生成和强度对纳米颗粒浓度不敏感。在油处于混相条件的实验中，使用所有测试的发泡溶液都能很容易地产生泡沫。由于形成了稳定的油/水乳液及其与泡沫共同作用降低二氧化碳流动性，有油存在时岩心尺度的泡沫表观粘度几乎是无油实验的三倍。
