Effect of Salinities on Supercritical CO 2 Foam Stabilized by a Betaine Surfactant for Improving Oil Recovery

作者：Weitao Li, Falin Wei, Chunming Xiong, Jian Ouyang, Mingli Dai, Liming Shao, Jing Lv · 发表于：Energy & Fuels · 年份：2019 · DOI：10.1021/acs.energyfuels.9b01688 · 被引用次数：39 · 研究领域：Enhanced Oil Recovery Techniques、Phase Equilibria and Thermodynamics、Petroleum Processing and Analysis

A zwitterionic surfactant, hexadecyl hydroxypropyl sulfo betaine, was examined for its ability to stabilize supercritical CO 2 (SC-CO 2 ) foam, with the goal of improving the oil recovery from mature oil fields with high temperatures and salinities. Herein, we present a detailed investigation of the effect of salinity on SC-CO 2 foam. First, the bulk foaming capacity was assessed for a betaine surfactant with different salinities, using a high-temperature, high-pressure (HTHP) foam generation apparatus. The effect of salinity on the rheology, flow resistance, and foam texture of the SC-CO 2 foams was characterized using a flow loop apparatus with a capillary tube and high-pressure visual cell that was under HTHP conditions. The stabilization mechanisms of the salinity for the SC-CO 2 foam were also explored by means of a HTHP interfacial tensiometer. Experimental results showed that the foaming volume slightly decreased, whereas the stability and apparent viscosity of the SC-CO 2 foam increased with increasing salinity. The foam half-life increased approximately 1.6-fold, from 22.2 to 35.2 min, while the apparent viscosity increased from 43.4 to 62 mPa s at 16 s –1 . The resistance factor of the steady-state CO 2 foam increased from 48 to 53 with increasing salinity, and the bubble size was approximately 10–20 μm during the core flooding experiments. The experiments indicated that the salinity could enhance the stability of the foam against film drainage and bubble coalescenc...