Interfacial tension behavior of athabasca bitumen/aqueous surfactant systems

Abstract

The spinning drop method was used to measure the interfacial tension of Athabasca bitumen in contact with an aqueous phase (D2O); variables included temperature, salinity, alkalinity, surfactant type (TRS 10–80, Suntech 5, sodium dodecyl sulfate), surfactant concentration, isopropyl alcohol concentration, bitumen drop size and age of interface. In the absence of surfactant, the bitumen/aqueous interfacial tension decreased with increasing temperature and salinity. Bitumen drops contacting alkaline medium exhibited interfacial tension minima below a pOH of three. In the presence of surfactant, the interfacial tension behavior was often complex. The interfacial tension‐concentration plot for Suntech 5 surfactant exhibited two CMC type discontinuities. Low interfacial tension (<0.01 mN m−1) was observed only in the presence of added electrolyte. Interfacial tension values were sensitive to the age of surfactant preparation and volume ratio of the oleic‐to‐aqueous phases. The interfacial tension of the bitumen/brine‐TRS 10–80 system increased upon addition of isopropyl alcohol. An increase in temperature required an increase in salinity to maintain a constant low interfacial tension. The experimental results are discussed in terms of changes in the structure of the amphiphile at the bitumen/aqueous interface.

Transient behavior of simultaneous flow of gas and surfactant solution in consolidated porous media

“…The IFT reduction is dependent on the extent and tile rates of adsorption and desorption of surfactant molecules at the oil/water interface [65,102,116]. Results show that IFT measured by the spinning drop method increases with time after an initial reduction, as shown in Figure 4.3.…”

“…On the other hand, result,s by Isa.acs eL al. [65] showed that injection of oil of up to 0.2 volume fraction had minimal detriment, al effect on foam mobility reduction. Robin [108] reported the results of experiments performed in a 12 Darcy sand.…”

“…However, the mobility reduction factor was lower by a factor of two. Limited variations in gas viscosities [92] show that the gas flow rate is inversely proportionM to gas' viscosity indicating Darcy flow, Steam foam behavior is similar to nitrogen _md CO2 foams, However, it is affected by changes in temperature and by pressure gradients which may cause steam foam to collapse, J Therefore, formulating steam foam with a _mall fraction of nitrogen gas increases its stability [30,34,35,38,65,74,87,100].…”

“…This makes foam better at controlling channeling due to permeability variation than a fluid with a constant viscosity. Foam formation required a critical gas velocity that was inversely proportional to the absolute permeability [65]. Effluent bubble size measurements indicate that lower permeability porous media generate smMler bubbles [44].…”

“…Results of IFT studies showing minima with tenlperature [1'2, 54], a minor dependence on temperature [12,54,65], a significant decrease with temperature [51], and an increase withtemperature [65,133] have ali been reported in the literature. The IFT--temperature behavior is a function of Salinity and is highly unpredictable [65].…”