EOR Potential of Mixed Alkylbenzenesulfonate Surfactant at Low Salinity and the Effect of Calcium on “Optimal Ionic Strength”

Abstract

The enhanced oil recovery (EOR) potential of different alkylbenzenesulfonate surfactants was investigated in a combined study of crude oil−water phase behavior and interfacial tension (IFT) and macroscopic oil displacement studies. In the presence of small amounts of calcium ions (calcium/sodium = 4 mol %), ultralow oil−brine IFT (<0.001 mN/m) was observed at ionic strengths 10 times lower than "optimal salinity" with sodium chloride only; this suggested an application in low salinity surfactant (LSS) EOR. "Optimal ionic strength" was determined for different calcium/sodium ratios in the brine, which further allowed prediction of phase behavior and IFT range for a given surfactant and a given crude oil at different brine compositions. In laboratory core floods, crude oil displacement by LSS with an optimal ionic strength electrolyte was around 9% higher than at "non-optimal" conditions.

Interactions between Surfactants and Cellulose Nanofibrils for Enhanced Oil Recovery

“…Recently, Tichelkamp et al 16 and Nourani et al 17 extensively studied sodium dodecylbenzene sulfonate (SDBS) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) for usage in enhanced oil recovery, and have shown promising potential within this field. The comprehensive knowledge base surrounding these surfactants renders them a suitable choice for studying possible synergistic effects between the surfactants and the cellulose nanofibrils and the low salinity water, and ultimately their combined performance efficiency for enhancing oil recovery.…”

Softened water application to improve micellar flooding performance

“…В представленном исследовании рассматривается технология мицеллярного заводнения пласта по сути, являющаяся разновидностью ПАВ заводнения. При мицеллярном заводнении пласта подбирается концентрация ПАВ необходимая для достижения критической концентрация мицеллообразования (ККМ), то есть минимальной концентрации ПАВ необходимой для образования устойчивых мицелл [4][5][6]. Образовавшиеся мицеллы, адсорбируясь на границе раздела нефть-вода, уменьшают поверхностное натяжение, приводя к образованию эмульсии нефти в воде.…”

Impact of Divalent Ions on Heavy Oil Recovery by in situ Emulsification

“…These ions can cause problems such as surfactant retention and precipitation. Calcium and sodium ratio, for instance, can also have an impact on the optimal ionic strength, which can affect the phase behavior and IFT of a surfactant and a crude oil (Tichelkamp et al, ).…”