Water-dispersible polymerÀsilica nanocomposite particles, SiO 2 Àethylene oxide-based polymer nanoparticles hybrids, were synthesized using a "grafting-from" method, where polymer brushes were grown on silica nanoparticles using living radical polymerization. Water-soluble polymer chains were grown from initiator-tethered 15-nm silica nanoparticles with ∼600 chains grafted per nanoparticle, resulting in a surface grafting of ∼1 chain per square nanometer. The single-phase and multiphase transport properties of low concentration brine dispersions of these polymer nanoparticles hybrids through a Berea sandstone core were measured. Experiments show that, while the viscosity increase is modest for dispersions with concentrations of 0.5À2 wt % of the nanoparticle hybrid, the dispersions were able to transport without hindrance through the porous media and, furthermore, were found to be effective at mobilizing waterflood residual oil.

The purpose of this work was to identify complexing agents and commercial scale inhibitors that can prevent scale formation in field brine during an ASP flood. The original field brine has near 1,000 ppm Ca++/Mg++ and 450 ppm HCO3− at pH 6 (Scale index, SI=0 at reservoir conditions). During ASP flooding, when the pH is increased to above 9, CaCO3 and MgCO3 scale occurs (SI=2.36). In order to prevent scaling during an ASP flood, divalent cations can be captured by addition of agents that form water-soluble complexes with metal ions in brine. With this purpose, six organic and two inorganic complexing agents as well as six different commercially available complexing agent brands have been tested. A working formulation with 11,000 ppm of an organic complexing agent was developed that can prevent scale formation up to pH values 10.5. The scale prevention capacity of four different commercial scale inhibitors were also tested alone and in combination with the mentioned complexing agents. Addition of 200 to 500 ppm of phosphonate or polyvinyl sulfonate based scale inhibitor helps drop the complexing agent concentration needed to prevent scale formation down to 5,500 ppm at pH values of 10.3 or less.

The success of chemical flooding rests heavily on the ability to deliver high-quality and repeatable surfactant in the field. While high-quality surfactants can easily be produced at lab scale, high oil recovery can be achieved only if similar quality product is produced at field scale. Scale-up of chemical production from batch-scale laboratory processes to field-scale continuous production requires a comprehensive program to evaluate surfactants produced at the bench-, pilot-plant and commercial scale to establish surfactant performance. Given the difference between batch-scale and continuous processes, small differences in surfactant structure can result thereby inducing differences in phase behavior and consequently oil recovery. Rigorous laboratory work is therefore required to synthesize and characterize surfactant samples in order to understand the correlation between structures/composition and performance in oil recovery. Following laboratory synthesis, pilot-plant studies are used to investigate process variables in order to understand their viability range and their impact on the large-scale product. Other important concerns are: optimal operational conditions, process repeatability, supply chain management, logistics, quality assurance/quality control, feedstock availability and dedicated procurement team. We present a case study for a proposed light oil surfactant polymer flood where a rigorous path for scale-up of surfactants from lab to pilot and finally field scale was evaluated via phase behavior experiments and coreflood testing. We show that phase behavior results are well correlated with coreflood recovery. For EOR, they are superior performance criteria to traditional specifications of physical and compositional properties for quality control. For the two-surfactant system presented herein, 272 surfactant samples, 512 formulations and 20 corefloods were conducted. The results from this large effort were utilized to develop appropriate manufacturing and quality-control processes to ensure the delivery of high-performance surfactants for field application.

The success of chemical flooding rests heavily on the ability to deliver high-quality and repeatable surfactant in the field. While high-quality surfactants can easily be produced at lab scale, high oil recovery can be achieved only if similar quality product is produced at field scale. Scale-up of chemical production from batch-scale laboratory processes to field-scale continuous production requires a comprehensive program to evaluate surfactants produced at the bench-, pilot-plant and commercial scale to establish surfactant performance. Given the difference between batch-scale and continuous processes, small differences in surfactant structure can result thereby inducing differences in phase behavior and consequently oil recovery. Rigorous laboratory work is therefore required to synthesize and characterize surfactant samples in order to understand the correlation between structures/composition and performance in oil recovery. Following laboratory synthesis, pilot-plant studies are used to investigate process variables in order to understand their viability range and their impact on the large-scale product. Other important concerns are: optimal operational conditions, process repeatability, supply chain management, logistics, quality assurance/quality control, feedstock availability and dedicated procurement team. We present a case study for a proposed light oil surfactant polymer flood where a rigorous path for scale-up of surfactants from lab to pilot and finally field scale was evaluated via phase behavior experiments and coreflood testing. We show that phase behavior results are well correlated with coreflood recovery. For EOR, they are superior performance criteria to traditional specifications of physical and compositional properties for quality control. For the two-surfactant system presented herein, 272 surfactant samples, 512 formulations and 20 corefloods were conducted. The results from this large effort were utilized to develop appropriate manufacturing and quality-control processes to ensure the delivery of high-performance surfactants for field application.