Preparation of Temperature-Sensitive SiO₂–PSBMA for Reducing the Viscosity of Heavy Oil

Abstract

Viscosity reduction by emulsification is one of the most effective methods for the recovery of heavy oil. Nanoparticles with low toxicity and low cost can stabilize oil-in-water (O/W) Pickering emulsions to reduce the viscosity of heavy oil and thereby have become a new type of emulsifier in recent years. The stimuli-responsive emulsions formed by responsive particles can achieve emulsification and demulsification under external stimuli, providing convenient conditions for heavy oil transportation and recovery, where the temperature response is easier to achieve. In this study, six groups of temperature-sensitive SiO2–PSBMA (PSBMA: polysulfobetaine methacrylate) with different particle sizes were prepared by the reverse atom transfer radical polymerization (RATRP) method. The morphologies of SiO2 particles before and after grafting were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM), and the structure of the product was characterized by Fourier transform infrared (FT-IR) spectroscopy, which showed that PSBMA was successfully grafted to SiO2. The grafting ratios (η) of six groups of SiO2–PSBMA measured by thermogravimetric analysis (TGA) were similar (34.50–42.94%). The temperature sensitivity of SiO2–PSBMA was determined by dynamic light scattering (DLS) and the contact angles at different temperatures, which showed that its upper critical solution temperature (UCST) was about 40–50 °C. SiO2–PSBMA was applied to GD2 heavy oil to reduce the viscosity at 60 °C, which showed that the SiO2–PSBMA had a good emulsification effect. With the increase of particle size, the viscosity reduction rate (VRR) showed a trend of first increase and then decrease. The highest VRR was 96.41%, achieved by 227.61 nm SiO2–PSBMA. All of the emulsions stabilized by SiO2–PSBMA were able to demulsify at room temperature. It can be used as an intelligent temperature-responsive viscosity reducer for heavy oil to control emulsions on demand.

A Feasibility Study on Enhanced Oil Recovery of Modified Janus Nano Calcium Carbonate-Assisted Alkyl Polyglycoside to Form Nanofluids in Emulsification Flooding

“…In water flooding, the viscosity of crude oil is much higher than that of fluid, which causes a phenomenon of fingertip protrusion, resulting in a decrease in the swept volume to decreased oil recovery. Therefore, the reduction of crude oil viscosity is beneficial to increase the swept volume, and enhance the displacement efficiency. − Figure shows the emulsion viscosity values under different conditions. The result of Figure A shows that under the same nanoparticle concentration, with the increase in temperature, the emulsion viscosity decreased.…”

Recyclable Fe3O4 Nanoparticles Responsive to Temperature for Heavy Oil Viscosity Reduction: Synthesis, Characterization, and Performance

“…The viscosity reduction rate (VRR%) was used to evaluate the viscosity reduction effect of the emulsifier, as shown in eq VRR % = μ 1 − μ 2 μ 1 × 100 where μ 1 is the viscosity of GD2 oil (The property curve of heavy oil can be found from the previous work) diluted with kerosene (The viscosity of the diluted heavy oil at 55 °C was 267 mPa·s.) and μ 2 is the viscosity of the heavy oil after emulsification.…”

“…However, biological methods usually have great limitations, such as temperature, salinity, etc., and the reproductive process of microflora is difficult to control . Emulsification − is an efficient and widely used method for chemical viscosity reduction. Natural surfactants such as asphaltenes and resins in heavy oil facilitate the formation of stable and viscous water-in-oil (W/O) emulsions .…”

Review of the Perspectives and Study of Thermo-Responsive Polymer Gels and Applications in Oil-Based Drilling Fluids

“…Wang et al [105] utilized reversible addition-fragmentation chain transfer polymerization (RATRP) to synthesize six groups of UCST temperature-responsive emulsifiers SiO 2 -PSBMA to reduce the viscosity of produced fluids (Figure 9). These emulsifiers' upper critical solution temperatures ranged between 40 and 50 • C and could demulsify at room temperature.…”