The behavior of SP crude oil defies the typical expectation that crude oil should exhibit lower phase inversion points (PIPs) and interfacial tension (IFT) at higher temperatures. To investigate these unique characteristics, emulsification experiments were conducted on SP oil at different temperatures. The emulsifying properties of various components of SP oil and maltene, with varying asphaltene contents, were further determined. The PIP of SP oil was observed to increase with temperature, ranging from 55 % at 50 degrees C to 85 % at 85 degrees C. Among the components of SP oil, only asphaltenes exhibited a slight resistance to the reduction of the PIP with increasing temperature. For maltene, the addition of asphaltene led to a higher PIP with increasing temperature. When the optimal mass ratio of resin to asphaltene was 5:1, the PIP increased from 65 % at 30 degrees C to 75 % at 60 degrees C. Furthermore, the interfacial properties of SP oil and its components at different temperatures were analyzed. The experimental results demonstrated that the IFT of SP oil increased with temperature. The dynamic IFT exhibited an increasing trend over time while maintaining relative stability. Among the components of SP oil, only asphaltenes exhibited an increase in IFT over time. For maltene, the addition of asphaltene resulted in an increase in IFT with increasing temperature.

多孔介质中,含油泡沫处于破裂与再生的动态平衡.利用Waring Blender法对原油与两性离子表面活性剂(RC)溶液进行重复剪切模拟含油泡沫再生,深入研究RC溶液与不同含量原油(0～60％)作用后,溶液性质及其再生泡沫起泡能力与稳定性的变化规律.结果表明,RC分子在油相及油水界面分配令起泡体系中的RC质量分数显著下降(最大降幅达到72％),原油在RC胶束中增溶令液膜稳定性明显减弱,两者共同作用下,RC溶液的再生泡沫性能严重受损.含油量40％以内,随含油量增加,一次剪切含油泡沫的析液半衰期不断延长直至无油泡沫的2.4倍,而二次剪切含油泡沫的析液半衰期持续降低直至无油泡沫的27％.二次剪切时,由于油水界面张力降低造成油相被乳化为大量小尺寸油滴,无法阻碍排液且易随水相析出,液膜内油量减少,二次剪切含油泡沫的泡沫半衰期与一次剪切含油泡沫相差较小.研究有助于进一步认识含油泡沫的再生行为,并对耐油起泡体系的构建具有积极意义.

The stability of betaine foam can be enhanced by salts in reservoirs, even the salinity up to 2×105 mg/L, which offers great potential for cost-effectively improving the gas mobility in high-salinity reservoirs. There is, however, a lack of understanding of the mechanisms behind this behavior. This paper focused on the surface and bulk phase properties of three betaines with alkyl chain lengths of C12 -C21 to probe the mechanisms leading to the high-salinityenhanced foam stability. Combining with the measurements of dilatational viscoelasticity, adsorption behaviors, surface relaxation, and micellar structure, the effects of salinity (2.3×104 -2.1×105 mg/L NaCl) on the surface and bulk phase properties were examined. With increasing salinity, betaine molecules adsorbed on the gas-water surface increased, and the molecule diffusion-exchange between the surface and bulk phase decelerated, resulting in the increased dilatational moduli and surface elasticity. The enhanced dilatational viscoelasticity slowed down the coarsening and coalescence, thus promoting the stability of betaine foam. The foam generated by oleicyl dimethyl amidopropyl carboxybetaine exhibited much stronger stability than the other betaine foams, especially when the NaCl concentration approached 2.1×105 mg/L. The wormlike micelle induced by high salinity dominated its superior stability.

The stability of betaine foam can be enhanced by salts in reservoirs, even with salinity as high as 2 x 10(5) mg/L, which offers great potential for cost-effectively improving the foam performance in high-salinity reservoirs. There is, however, a lack of understanding of the mechanisms behind this behavior. This study focused on the surface and bulk phase properties of three betaines with alkyl chain lengths of C-12-C-21 to probe the mechanisms leading to the high-salinity-enhanced foam stability. The dilatational viscoelasticity, adsorption behavior, surface relaxation, rheology, and thin-film drainage were examined in a wide NaCl range of 2.3 x 10(4) to 2.1 x 10(5) mg/L. With increasing salinity, betaine molecules adsorbed on the gas-water surface increased, and molecule diffusion-exchange between the surface and bulk phase decelerated, resulting in increased dilatational moduli and surface elasticity. The enhanced dilatational viscoelasticity slowed coarsening and coalescence, thus promoting the stability of betaine foam. The foam generated by oleicyl dimethyl amidopropyl carboxybetaine exhibited much stronger stability than the other betaine foams, especially when the NaCl concentration approached 2.1 x 10(5) mg/L. The viscoelastic micelle induced by high salinity dominated its superior stability.