Viscosity and Phase Behavior of Petroleum Sulfonate Solutions in the Liquid Crystalline Region
| Autor: | C.A. Miller, Olina Ghosh, S.K. Baijal, William J. Benton, Syed Qutubuddin |
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| Rok vydání: | 1987 |
| Předmět: | |
| Zdroj: | SPE Reservoir Engineering. 2:664-670 |
| ISSN: | 2469-9683 0885-9248 |
| DOI: | 10.2118/12700-pa |
| Popis: | Summary Aqueous solutions of two petroleum sulfonate surfactants, a pure sulfonate surfactant and one mixed with an ethoxylated sulfate surfactant, were studied with polarizing microscopy, polarized light screening (PLS), and viscometry. The same sequence of phases was seen with increasing salinity for the various surfactants—i.e., transformation from an isotropic micellar solution to a lamellar liquid crystalline phase to an isotropic phase that scattered light and exhibited streaming birefringence. Addition of calcium ions to the petroleum-sulfonate/ethoxylated-sulfate mixtures led to the same basic sequence of transformations, but the effect of calcium was about 11.5 times as great as that of sodium on a molar basis. Many small crystalline particles were also observed when calcium was present. A cone-and-plate viscometer was used to measure the apparent viscosity of the various solutions. A maximum in apparent viscosity was always found in the transition region between a dispersion of spherulitic liquid crystalline particles in an aqueous phase and a single liquid crystalline phase. The maximum occurred whether the transition was brought about by changes in salinity, divalent cation concentration, oil content, or other compositional variables. Apparent viscosity generally decreased with increasing temperature, although dependence on temperature was not monotonic at high salinities. Apparent viscosity decreased with increasing shear rates and was time-dependent at a given shear rate. At low salinities, apparent viscosity generally decreased with time. At high salinities, apparent viscosity frequently increased with time. |
| Databáze: | OpenAIRE |
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