APPLICATION OF NANOPARTICLES AS PROPPANTS AND BREAKER ENCAPSULATING AGENTS

Abstract

Permeability reduction of proppant pack caused by incomplete degradation of filter cake near the tip of the fractures have been previously reported. It has been previously proven that polyethylenimine-dextran sulfate (PEI-DS) nano-particles can delay the release of enzymes which reduce the viscosity of cross-linked guar. This delayed release would help in injecting higher concentrations of enzymes by encapsulating the enzyme inside nano-particles. However, performance of these nano-particles in reaction with high concentration filter cakes has not been studied yet. As a part of this research, long term fracture conductivity of the proppant pack, containing PEI-DS nano-particles as the encapsulating agent, was studied to determine the feasibility of using them as enzyme breaker carriers and fluid loss additives for hydraulic fracturing applications. Fracturing jobs in tight shale plays using slickwater fluids tend to generate or extend a large network of micro-fractures during the injection of fracturing fluids. Conventional proppants (0.8382 mm to 104.14 µm) are large enough to create conductivity in the larger primary fractures but not small enough to penetrate into the existing or generated micro-fractures. This will cause the closure of micro-fractures at the end of the fracturing job thereby reducing the length and conductivity of the complex fracture network. The second part of this work is focused on investigating the size, nano-hardness, reduced elastic modulus and fluid loss prevention capabilities of fly ash nano-particles as well as the fracture conductivity induced by them when used as nano-proppants.