Cationic coatings for improved nanoparticle transport in a carbonate reservoir

A method for enhancing oil recovery comprising:

• introducing a drilling fluid comprising an aqueous base fluid and a group of coated nanoparticles to a carbonate reservoir, the carbonate reservoir having a net-positive charge, in which the group of coated nanoparticles consist of nanoparticles and a cationic coating, in which:
• each of the nanoparticles is coated with the cationic coating,
• the cationic coating has a net-positive charge, and
• the drilling fluid does not include coated nanoparticles having a net-negative charge;
• and
• injecting the drilling fluid comprising the coated nanoparticles into the carbonate reservoir to displace oil in the carbonate reservoir and thereby enhance the oil recovery, the coated nanoparticles being retained within the drilling fluid with reduced agglomeration in the carbonate reservoir due to electrostatic repulsion, the electrostatic repulsion being produced by the interaction of the positive charge of the coated nanoparticles and the positive charge of the carbonate reservoir.

A method for enhancing oil recovery comprising:

• introducing a drilling fluid consisting essentially of an aqueous base fluid and a group of coated nanoparticles to a carbonate reservoir, the carbonate reservoir having a net-positive charge, in which:
• the group of coated nanoparticles consist of nanoparticles and a cationic coating,
• each of the nanoparticles is coated with the cationic coating, and
• the cationic coating has a net-positive charge;
• and
• injecting the drilling fluid into the carbonate reservoir to displace oil in the carbonate reservoir and thereby enhance the oil recovery, the coated nanoparticles being retained within the drilling fluid with reduced agglomeration in the carbonate reservoir due to electrostatic repulsion, the electrostatic repulsion being produced by the interaction of the positive charge of the coated nanoparticles and the positive charge of the carbonate reservoir.