Study on multi-scale oil displacement mechanism polymer/nanoparticle composite flooding

Area of Science:

• Petroleum Engineering
• Materials Science

Background:

• Conventional polymer flooding is a key enhanced oil recovery (EOR) method.
• Challenges include high polymer dosages and poor shear resistance, limiting effectiveness and increasing environmental concerns.

Purpose of the Study:

• To investigate the feasibility of a polymer/nanoparticle composite flooding method for improved EOR.
• To address limitations of conventional polymer flooding, such as dosage and shear resistance.

Main Methods:

• Characterization of rheological properties and interfacial tension of polymer/nano-SiO2 systems.
• Microscopic morphology analysis using scanning electron microscopy (SEM).
• Microscopic and core flooding experiments to assess sweep efficiency, residual oil distribution, injection pressure, and recovery efficiency.

Main Results:

• Nano-SiO2 addition significantly enhanced polymer system viscosity through nanoparticle adsorption onto polymer chains, forming network structures.
• The composite system demonstrated increased sweep efficiency and altered residual oil patterns from reticulated to cluster, membrane, and punctiform.
• Reduced usage, improved injectivity, a 6% higher recovery rate, and a 14% reduction in injection pressure were observed compared to conventional polymer flooding.

Conclusions:

• The polymer/nano-SiO2 composite flooding method is a viable and superior alternative to conventional polymer flooding for EOR.
• This approach offers enhanced performance, reduced environmental impact, and improved operational efficiency.