Stability improvement of foams for enhanced oil recovery applications using polyelectrolytes and polyelectrolyte complex nanoparticles

a non-liquid fluid phase comprising N2 in a supercritical phase;

• and
• a liquid dispersion phase comprising a dispersion of polyelectrolyte material and surfactant in water, wherein:
• the polyelectrolyte material and the surfactant are combined in a ratio of surfactant to polyelectrolyte material ranging from 3:1 to 9:1;
• the polyelectrolyte material is present in an amount ranging from about 0.01% to 5% of the liquid phase by weight;
• and
• the polyelectrolyte material forms nanoparticles by electrostatic interaction of a cationic and an anionic polyelectrolyte, the nanoparticles being located at lamellae of the liquid dispersion phase in an effective amount to stabilize the foam.

A method of foam flooding, comprising the steps of:

• introducing a foam into an injection wellbore, the foam comprising:
• a non-liquid fluid phase comprising N2 in a supercritical phase;
• and
• a liquid dispersion phase comprising a dispersion of polyelectrolyte material and surfactant in water, wherein:
• the polyelectrolyte material and the surfactant are combined in a ratio of surfactant to polyelectrolyte material such that a concentration of the surfactant is below a critical micelle concentration;
• the polyelectrolyte material is present in an amount ranging from about 0.01% to 5% of the liquid phase by weight;
• and
• the polyelectrolyte material forms nanoparticles by electrostatic interaction of a cationic and an anionic polyelectrolyte, the nanoparticles being located at lamellae of the liquid dispersion phase in an effective amount to stabilize the foam;
• and
• wherein the foam has a foam quality ranging from 60% to 90% of the total foam volume occupied by the non-liquid fluid phase;
• flowing the foam through the injection wellbore for subsequent introduction into rock of an oil reservoir;
• flooding the foam from the injection wellbore on a pathway extending from the injection wellbore through the oil reservoir and towards one or more producing wellbores to enhance recovery of oil in place from the oil reservoir.

A foam, comprising:

• a non-liquid fluid in a supercritical phase;
• and
• a liquid dispersion phase comprising a dispersion of polyelectrolyte material and surfactant in water, wherein:
• the polyelectrolyte material and the surfactant are combined in a ratio of surfactant to polyelectrolyte material such that a concentration of the surfactant is below a critical micelle concentration;
• the polyelectrolyte material is present in an amount ranging from about 0.01% to 5% of the liquid phase by weight;
• and
• the polyelectrolyte material forms nanoparticles by electrostatic interaction of a cationic and an anionic polyelectrolyte, the nanoparticles being located at lamellae of the liquid dispersion phase in an effective amount to stabilize the foam;
• wherein the foam has a foam quality ranging from 60% to 90% determined as a percentage total foam volume occupied by the gas phase.