The phase behavior for systems containing sodium bis (2-ethylhexyl sulfosuccinate) (AOT), with the cationic hydro-trope tetraethyl ammonium chloride (TEAC), in the presence of water and heptane were studied. Formulati...The phase behavior for systems containing sodium bis (2-ethylhexyl sulfosuccinate) (AOT), with the cationic hydro-trope tetraethyl ammonium chloride (TEAC), in the presence of water and heptane were studied. Formulations of mi-croemulsion for such systems and for systems containing the so called “extended surfactant” were carried out at different salt concentrations. Anisotropy was detected using cross polarizers and polarized microscopy. Ultralow interfacial tension for microemulsion was measured, first theoretically using the Chun-Huh equation, and then experimentally using spinning drop experiments. The presence of short chain hydrotropes (TEAC) was found to destabilize the liquid crystalline region, observed in the AOT/water/heptane phase diagram. Ultralow interfacial tensions were observed for microemulsions formulated with surfactant concentrations as low as 0.5%, for both AOT and “extended surfactant” systems. The effect of temperature on the phase behavior of a microemulsion formed with AOT system was studied and found to behave in an opposite manner compared to the nonionic surfactant.展开更多
In this paper, as far as the ASP flooding in the pilot area of Daqing oilfield is concerned, the effect of apparent viscosity of ASP solution on enhanced oil recovery have been studied by comparison of experiments on ...In this paper, as far as the ASP flooding in the pilot area of Daqing oilfield is concerned, the effect of apparent viscosity of ASP solution on enhanced oil recovery have been studied by comparison of experiments on artificial heterogeneous cores with on natural cores. The results showed that the decrease in the concentration of alkali could increase the apparent viscosity of ASP solutions, namely, the apparent viscosity increased and the IFT couldn’t get ultra low, and the oil recovery efficiency by ASP solution with a reasonably lower concentration of alkali was not less than that with a higher concentration of alkali and ultra low IFT. The experiments with models having impermeable interlayers between adjacent layers, and by means of “co-injection and separate production” showed that the ASP solution with a higher viscosity and a lower alkali concentration was more beneficial to starting-up medium and low permeability layers and enhancing total oil recovery. Therefore, to heterogeneous reservoir, as factors of affecting oil recovery, the apparent viscosity may be more important than the ultralow IFT. Furthermore, on the premise that the concentration of surfactant and the concentration of polymer keep constant, ASP flooding with low alkali concentration not only enlarges the selectable range of surfactants and decreases the cost of ASP flooding, but also solves the problem of alkali scales. Finally, a dynamic absorption experiment was performed with a 05 meter long linked-up natural core to determine alkali wastage in formation. The result being accord with the application case in the pilot confirmed that it was not necessary to add the alkali too much in ASP flooding from a new direction.展开更多
文摘The phase behavior for systems containing sodium bis (2-ethylhexyl sulfosuccinate) (AOT), with the cationic hydro-trope tetraethyl ammonium chloride (TEAC), in the presence of water and heptane were studied. Formulations of mi-croemulsion for such systems and for systems containing the so called “extended surfactant” were carried out at different salt concentrations. Anisotropy was detected using cross polarizers and polarized microscopy. Ultralow interfacial tension for microemulsion was measured, first theoretically using the Chun-Huh equation, and then experimentally using spinning drop experiments. The presence of short chain hydrotropes (TEAC) was found to destabilize the liquid crystalline region, observed in the AOT/water/heptane phase diagram. Ultralow interfacial tensions were observed for microemulsions formulated with surfactant concentrations as low as 0.5%, for both AOT and “extended surfactant” systems. The effect of temperature on the phase behavior of a microemulsion formed with AOT system was studied and found to behave in an opposite manner compared to the nonionic surfactant.
文摘In this paper, as far as the ASP flooding in the pilot area of Daqing oilfield is concerned, the effect of apparent viscosity of ASP solution on enhanced oil recovery have been studied by comparison of experiments on artificial heterogeneous cores with on natural cores. The results showed that the decrease in the concentration of alkali could increase the apparent viscosity of ASP solutions, namely, the apparent viscosity increased and the IFT couldn’t get ultra low, and the oil recovery efficiency by ASP solution with a reasonably lower concentration of alkali was not less than that with a higher concentration of alkali and ultra low IFT. The experiments with models having impermeable interlayers between adjacent layers, and by means of “co-injection and separate production” showed that the ASP solution with a higher viscosity and a lower alkali concentration was more beneficial to starting-up medium and low permeability layers and enhancing total oil recovery. Therefore, to heterogeneous reservoir, as factors of affecting oil recovery, the apparent viscosity may be more important than the ultralow IFT. Furthermore, on the premise that the concentration of surfactant and the concentration of polymer keep constant, ASP flooding with low alkali concentration not only enlarges the selectable range of surfactants and decreases the cost of ASP flooding, but also solves the problem of alkali scales. Finally, a dynamic absorption experiment was performed with a 05 meter long linked-up natural core to determine alkali wastage in formation. The result being accord with the application case in the pilot confirmed that it was not necessary to add the alkali too much in ASP flooding from a new direction.
