Synergistic Effects between Different Types of Surfactants and an Associating Polymer on Surfactant–Polymer Flooding under High-Temperature and High-Salinity Conditions

Abstract

The synergistic effects of surfactant–polymer (SP) flooding under high-temperature and high-salinity (HTHS) conditions were investigated for a hydrophobically associating polyacrylamide (HAPAM) mixed with different types of surfactants. The hydrophobic group of the polymer is positively charged. All surfactants contain 12 carbons at the hydrophobic chain. The list of surfactants included a cationic surfactant (DTAB: dodecyl trimethylammonium bromide), an anionic surfactant (SDS: sodium dodecyl sulfate) and a nonionic surfactant (DDG: dodecyl glucopyranoside). The physical properties of various SP solutions, prepared in high-salinity water, were evaluated using formulations composed of 0.2 g/L polymer and different concentrations of surfactants. Upon the addition of surfactants, the zero-shear viscosity (η0) of the polymer solution was found to peak at ∼0.15 g/L (0.4 mM) of surfactant for the HAPAM/SDS and HAPAM/DDG solutions. However, the HAPAM/DTAB solution did not show a viscosity maximum with increases in surfactant concentration due to the electrostatic repulsion between the hydrophobic units of the polymer and DTAB. At a representative reservoir temperature of 90 °C, the η0 value of the HAPAM/SDS solution is significantly higher than that of other SP solutions when η0 peaks, indicating that more HAPAM polymer chains are connected at a high temperature via the electrostatic attraction between hydrophobic pendants of the polymer and SDS. The interfacial tension (IFT) results demonstrate an SP synergistic effect on the IFT reduction with the HAPAM/SDS and HAPAM/DTAB solutions at 90 °C, while no such effect was observed for the HAPAM/DDG solution, suggesting that the arrangement of DDG molecules at the oil–water interface is not altered by the polymer. At 90 °C and a surfactant concentration of 0.4 g/L, the HAPAM/SDS solution exhibits the highest viscosity along a sufficiently low IFT. Subsequent micromodel experiments indicated that the volumetric sweep efficiency was significantly enhanced by HAPAM/SDS flooding. The efficiency of oil production with the HAPAM/SDS formulation in the secondary recovery mode was higher than with other SP systems. This study probes the synergistic interactions in SP slugs at a molecular level under HTHS reservoir conditions to reveal their potential effects and correlation to the effectiveness of oil production enhancement.

Rheological Properties of a New Microbial Exopolysaccharide Produced by Sphingomonas sp. HS and Its Potential in Enhanced Oil Recovery

“…Among those technologies, the ASP flooding technology has exhibited a good efficiency of enhancing oil recovery. Mainly, water-soluble polymers are used to increase the volume scanning efficiency, and surfactants/alkali are used to minimize the oil–water interfacial tension (IFT), thereby improving microdisplacement efficiency . However, the presence of alkali in the ASP system causes the dispersion and migration of clay and alkaline scaling in the formation, leading to the decrease of reservoir permeability, which may cause wellbore scaling and formation plugging and even the alkalization of the formation after long-term injection. , Inspirationally, the surfactant–polymer (SP) binary system, which combines the viscoelasticity of the polymer with the ability of surfactant to reduce surface tension, has become a rising interest in tertiary oil recovery.…”

Behavior study of a thermo‐responsive hydrophobically associative water‐soluble terpolymer in laboratory test with heavy crude oil

“…3 In this sense, novel methods such as pyrolysis or injection of surfactants, biopolymers, and synthetic polymers have been developed for enhancing the recovery of crude oil embedded into reservoirs. It is worth mentioning that these methods have been extensively investigated and some of them have already been applied in reservoirs [4][5][6] Among the polymer flooding process, the use of hydrophobically associating water-soluble polymers (HAWSPs) represents the most robust system due to the ability of these polymers to form reversible network able to improve the viscosity of the water medium allowing the mobility of the crude oil and therefore enhance its extraction. In fact, the major challenge in the application of associative polymer as flooding agents for enhancing the EOR process related to the capacity of these polymers to maintain their viscosities within the reservoirs and this under harsh conditions and prolonged times.…”

Preparation and properties of a clean, low‐damage waterproof locking damage multifunctional integrated water‐based fracturing fluid

“…Aqeous hydroxyl aqueous solution was used to replace solvent oil in the liquid thickener system to avoid environmental pollution caused by the solvent oil. In addition, the aqueous system can significantly improve the dissolution rate of hydrophobically‐associating polymers, while SDS can effectively enhance the hydrophobic association strength and improve the solution viscosity 29 . As a non‐ionic surfactant, CDEA is compatible with various other surfactants 30 .…”

“…In addition, the aqueous system can significantly improve the dissolution rate of hydrophobically-associating polymers, while SDS can effectively enhance the hydrophobic association strength and improve the solution viscosity. 29 As a non-ionic surfactant, CDEA is compatible with various other surfactants. 30 SMA and ODAAC have non-ionic and cationic properties.…”