Hyper-branched structure-an active carrier for copolymer with surface activity, anti-polyelectrolyte effect and hydrophobic association in enhanced oil recovery

Advancements in Surfactant Carriers for Enhanced Oil Recovery: Mechanisms, Challenges, and Opportunities

Enhanced oil recovery (EOR) techniques are crucial for maximizing the extraction of residual oil from mature reservoirs. This review explores the latest advancements in surfactant carriers for EOR, focusing on their mechanisms, challenges, and opportunities. We delve into the role of inorganic nanoparticles, carbon materials, polymers and polymeric surfactants, and supramolecular systems, highlighting their interactions with reservoir rocks and their potential to improve oil recovery rates. The discussion includes the formulation and behavior of nanofluids, the impact of surfactant adsorption on different rock types, and innovative approaches using environmentally friendly materials. Notably, the use of metal oxide nanoparticles, carbon nanotubes, graphene derivatives, and polymeric surfacants and the development of supramolecular complexes for managing surfacant delivery are examined. We address the need for further research to optimize these technologies and overcome current limitations, emphasizing the importance of sustainable and economically viable EOR methods. This review aims to provide a comprehensive understanding of the emerging trends and future directions in surfactant carriers for EOR.

Experimental and Theoretical Investigation of Glycol-Based Hydrogels through Waterflooding Processes in Oil Reservoirs Using Molecular Dynamics and Dissipative Particle Dynamics Simulation

Enhanced oil processing aims to retrieve petroleum fluids from depleted reservoirs after traditional processing. Hydrogels and polymeric macromolecules are considered effective displacing agents in oil reservoirs. In the current work, the authors used hydrophilic hydrogels based on poly(ethylene glycol)/poly(propylene glycol) (PEG/PPG) surfmers for oil displacement processes. Statistical modeling of the rheological properties at 80 °C for the two hydrogels indicates that the viscosity-shearing profile obeys the power-law model. Also, shear stress scanning follows the Herschel-Bulkley and the Bingham plastic models. The two hydrogels exhibit an initial yield stress owing to the formation of a three-dimensional (3D) structure at zero shearings. Furthermore, PEG and PPG hydrogels can retain the viscosity after a shear rate of 64.68 S-1. On the scale of surface activity, the two hydrogels exhibit higher surface areas (A m) of 0.1088 and 0.1058 nm2 and lower surface excess concentrations (Γm) of 1.529 and 1.567 × 1010 mol/cm2, respectively. A molecular dynamics (MD) simulation was conducted to explore the Flory-Huggins chi parameter, the solubility parameter, and the cohesive energy density. The results indicate a negative magnitude of chi parameter (χ ij ) for water and salt, which indicates that the two hydrogels have a good tendency toward saline formation water in the underground petroleum reservoir. Furthermore, the dissipative particle dynamics (DPD) was performed on a mesoscale to investigate the interfacial tension, the radius of gyration, the concentration profile, and the radial distribution function. The increased radius of gyration (R g) confirms that the two hydrogels are more overextended and can align perpendicularly toward the water/oil boundary. Experimental displacement was operated on a linear sandpack model using different slug concentrations. The oil recovery factor, the water-cut, and the differential pressure data during the flooding process were estimated as a function of the injected pore volume. The obtained results show that the oil recovery factor reaches 72 and 88% in the cases of PEG and PPG hydrogels at 80 °C with concentrations of 1.0 and 1.5 g/L, which reveals that both hydrogels are effective enhanced oil recovery (EOR) agents for the depleted reservoirs. This study establishes a new route that employs MD and DPD simulation in the field of enhanced oil recovery and the petroleum industry.

A Thermal Thickening System Based on the Self-Assembly of a Zwitterionic Hydrophobic Association Polymer and Surfactant

The zwitterionic monomer, 1-(2-hydroxypropyl-sulfo)-acrylamide ethyl-N,N-dimethyl ammonium chloride (MeSA) was copolymerised with acrylamide (AM), acrylic acid (AA), and a hydrophobic monomer N,N-diallyl oleamide (DNDA) to obtain the zwitterionic hydrophobic association polymer AM/AA/DNDA/MeSA. The structure of the hydrophobic association polymer was characterised by 1H NMR, FT-IR, and intrinsic viscosity studies. The self-assembly system of the polymer and the surfactant Tween-40 was then formed, and the rheological properties and adsorptive performance of the self-assembly system were investigated. The result showed that the polymer–surfactant self-assembly system had good properties such as thickening, temperature resistance, salt resistance, and shear resistance. It is shown that the thermal thickening phenomenon, which allows the system to be used as a good petrochemical product in a high-temperature environment, provides a vital research foundation for the future application of this kind of self-assembly system.