Polymer flooding, an augmented waterflooding method, has been evaluated Polymer flooding, an augmented waterflooding method, has been evaluated comprehensively in the laboratory and extensively field tested. This paper reviews past industrial experience, appraises current technology, paper reviews past industrial experience, appraises current technology, defines screening guidelines for field use, and discusses the future of the process. Introduction The petroleum industry recognized the problem of inefficient oil recovery by conventional (primary and secondary) recovery methods in the early 1900's. Since then, extensive research has been conducted on improvement of displacement and sweep efficiency in petroleum recovery. Many different processes have been designed to improve displacement efficiency by reducing residual oil saturation. However, polymer flooding was designed to improve sweep efficiency by improving the mobility ratio. Muskat first pointed out that fluid mobilities would affect waterflood performance. In 1949-50, Stiles used permeability and capacity distribution in waterflood permeability and capacity distribution in waterflood calculations and Dykstra and Parsons showed the effect of permeability variation and mobility ratio on recovery. permeability variation and mobility ratio on recovery. Aronofsky and Ramey discussed the mobility ratio and its influence on flood patterns during water encroachment in 1952 and on injection and production histories in a five-spot waterflood in 1956. In 1954, Dyes et al. presented studies of the influence of mobility ratio on oil presented studies of the influence of mobility ratio on oil production after breakthrough. Later, Caudle and Witt production after breakthrough. Later, Caudle and Witt (1959) and Barnes (1962) suggested improving waterflood sweep efficiency by increasing water viscosity. However, it was not until 1964 that Pye and Sandiford established that the mobility of water (or brine) used in waterflooding can be reduced efficiently by adding small amounts of a water soluble polymer. Since then, significant laboratory studies have appeared sustaining and extending this information. Recently, several additional important properties the inaccessible pore volume, shear degradation in porous media, and polymer retention have been observed. In addition to the laboratory findings, field test results also have appeared in the literature. Detailed summaries of these field reports were given by Jewett and Schurtz, Sloat, Agnew, and Herbeck et al. This paper reviews the process development, discusses current status, and assesses the future potential of polymer-flooding technology. polymer-flooding technology. Process Description Process Description Polymer flooding is an enhanced oil-recovery process Polymer flooding is an enhanced oil-recovery process that uses polymeric additives at concentrations of 250 to 1,500 ppm in the flood water. The polymer solution improves the water-oil mobility ratio; this results in the reservoir being swept more completely than if flooded with water not containing additives to reduce mobility. Currently, two types of polymers are used (1) a synthetic polymer classified as a polyacrylamide (partially polymer classified as a polyacrylamide (partially hydrolyzed), and a biologically produced polymer known as xanthan gum. In addition to increasing viscosity, polyacrylamides alter the permeability of the reservoir rock; this also lowers the effective mobility of the injected water. When the permeability of reservoir rock is reduced, a lower polymer concentration can be used to gain equivalent polymer concentration can be used to gain equivalent mobility control.
Polymer flooding (PF) and alkaline/surfactant/polymer (ASP) flooding have been applied throughout the world for more than 20 years.
Nonionic triblock copolymers, surfactant Pluronic F68 (PEO76-PPO29-PEO76), are widely used in industrial processes, such as foaming, emulsification, and stabilization. The behaviors of triblock copolymers such as the salt-dependent self-assembly in bulk solution and the irreversible adsorption at the oil/water interface are mainly focused to explore their effects on the interaction forces between nano-spacing interfaces of oil droplets. In this study, the atomic force microscopy (AFM) technique was employed to measure the drop interaction forces with different F68 bulk concentrations. All selected bulk concentrations (≥100 μM) of copolymers can ensure the formation of a stable layer structure of stretched polymer chains ("brush") at the oil/water interface, which behaved as a mechanical barrier at the interface. This study quantified the forces caused by the space hindrance of F68 copolymers both in the bulk phase and at the interface of oil/F68 aqueous solution during drop interaction. The effects of monovalent electrolyte (NaCl)-induced self-assembly behavior of triblock copolymers F68 in bulk solution on drop interaction forces were measured through the AFM technique.
Creating surfaces with controlled superoleophobicity is of real significance for the manipulation, transportation, and self-cleaning of organic fluids of strategic importance. In the present work, particular attention is given to elucidate the superoleophobicity mechanism of surfaces coated with polyelectrolyte multilayers (PEMs) assembled by layer-by-layer deposition of the cationic polyelectrolyte polydiallyldimethylammonium chloride (PDDA) and the anionic polyelectrolyte poly(styrenesulfonate) (PSS) in 1.0 M NaCl solution. The atomic force microscopy (AFM) drop probe technique was used to measure the salinity-specific adhesion forces between the oil droplet and underwater polyelectrolyte PEM-coated surface. Meanwhile, topographic images of the fabricated PEMs in solutions with different ionic strengths were also obtained and compared. The results show that the fabricated (PDDA/ PSS) 1.5 , (PDDA/PSS) 3.5 , and (PDDA/PSS) 4.0 PEMs exhibit excellent oil repellency upon immersion into aqueous solutions with high salinity. Additionally, the underwater superoleophobicity of the prepared PEM films was well-demonstrated through AFM adhesion force measurements. It is proven in our study that the underwater superoleophobicity of the fabricated surface has a strong relationship with the salinity-specific behavior of deposited polyelectrolytes.
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