Mixtures of Anionic-Cationic Surfactants: A New Approach for Enhanced Oil Recovery in Low-Salinity, High-Temperature Sandstone Reservoir

Abstract

Test results from mixtures of anionic-cationic surfactants significantly broaden the application scope for conventional chemical Enhanced Oil Recovery methods; these mixtures produced ultra low Critical Micelle Concentrations (CMC) as well as ultra-low interfacial tension (IFT) and high oil solubilization that promote high oil recovery.Mixtures of anionic and cationic surfactants with molar excess of anionic surfactant for EOR applications are described herein. Physical chemistry properties, such as surface tension, CMC, surface excess and area per molecule of individual surfactants and their mixtures were measured by Wilhelmy Plate Method. Morphologies of surfactant solutions, both surfactant-polymer (SP) and alkaline-surfactant-polymer (ASP), were studied by Cryo TEM. Phase behaviors were recorded by visual inspection including with crossed polarizers at different surfactant concentrations and different temperatures. Interfacial tensions between normal octane, crude oil and surfactant solution were measured by spinning drop tensiometer method. Properties of interfacial tension, viscosity and thermal stability of surfactant, surfactant-polymer, and alkalinesurfactant-polymer solutions, were also tested. Static adsorption on sandstone was measured at reservoir temperature. IFT was measured before and after multiple contact adsorptions to recognize the influence of adsorption on interfacial properties. Forced displacements were conducted by flooding with water, polymer, SP and ASP. The core flooding experiments were conducted with water made of a simulated formation brine having approximately 5000 ppm TDS, and with a crude oil from a Sinopec reservoir.

How to Attain Ultralow Interfacial Tension and Three‐Phase Behavior with Surfactant Formulation for Enhanced Oil Recovery: A Review. Part 4: Robustness of the Optimum Formulation Zone Through the Insensibility to Some Variables and the Occurrence of Complex Artifacts

“…Adapted from previous data [114] anionic, has allowed the using a water-soluble catanionic for EOR purpose. In such cases, two close minimum tensions and a relatively wide three-phase zone take place close to the AI/CI 1:1 mixture condition [236][237][238][239].…”

ASP Flooding: Theory and Practice Progress in China

“…The compounding of surfactant can reduce IFT, such as the compounding of petroleum sulfonate and carboxylate [38] and the compounding of biological surfactants Rhamnolipid broth and normal surfactant [39]. IFT contrast between single surfactant and surfactants mixtures is very obvious and the mixture surfactants has much lower IFT and concentration to form lower IFT [40]. We can see that the mixture surfactant Sa/c surface tension is much lower than single surfactant Sa or Sc.…”

“…We can see that the mixture surfactant Sa/c surface tension is much lower than single surfactant Sa or Sc. Surfactants mixture is good and cheap way to find low IFT surfactants required [40]. In field tests Henan, Shengli, and Xinjiang, the mixtures surfactants were used.…”

Synthesis of stable nanoparticles at harsh environment using the synergistic effect of surfactants blend

“…They observed that the thickness of ionic media around mixed micelles is decreased by increasing ethoxylated surfactant molecules. A synergistic effect of different mixed surfactant systems for EOR applications is subsequently proposed 25,26 .…”