Structure Property Relationship of Novel Nano-Hybrids for Hydraulic Fracturing Applications

Abstract

Abstract The unique properties of polymer nano-hybrids, which not only make them obvious technology materials, but also provide a convenient macroscopic system to study fundamental scientific issues concerning confined and tethered polymers, have sparked the attention of material developers. Studying the formation, structure and dynamics of polymer nano-hybrids can lead to a better understanding of organic-inorganic hybrids, polymers in confined environment or at a solid interface. Proppant are an integral part of hydraulic fracturing operations. Resin coated proppants are widely used in hydraulic fracturing applications to increase the strength of proppant material to withstand closure stresses and to mitigate any proppant flowback. In this paper we showcase the development of novel nano-hybrid materials that enhance the proppant physico-chemical properties. We present an investigation of novel polymer nano-hybrids based on emulsified resin and nanofillers having one dimension in nanoscale. The resins used for proppant coating are introduced as a water external emulsion, thus making them compatible with the aqueous fracturing fluids. We show that by using a solid resin-based emulsion system as proppant coating material we could introduce this system on the fly, along with the fracturing fluid without facing any incompatibility issues between the hydrophobic resin and the aqueous fracturing fluid. We further show that by using tactoid-based filler materials dispersed within the emulsified resin we could tremendously enhance the overall physico-chemical properties of the proppants. It is also shown that this property enhancement is dependent on the structure of the nano-hybrid. In polymer nano-hybrids using tactoid based nano-fillers, better dispersion of nano-fillers in the polymer matrix can be achieved by organic modification filler surface, rendering the filler surface hydrophobic, thereby facilitating the delamination of the tactoid individual layers into nanoscale platelets by the polymer chains. The dispersion of nano-size layers in the resin matrix, markedly improves physico-chemical properties as compared to pristine resin. We have shown that the delamination of the individual tactoid layers and their uniform dispersion in the resin matrix was the key aspect that governed the tremendous property increment in the nano-hybrid coated proppants. A microstructural evaluation of these nano-hybrid coated proppants is presented and correlated to the proppant property enhancement. Novelty of this paper is the development of new nano-hybrid based proppant coating materials that lead to tremendous physico-chemical property enhancement as well as on-the-fly deployment of the proppant coating material along with fracturing fluid due to enhanced compatibility.