Self-healing elastomer modified proppants for proppant flowback control in hydraulic fracturing

To address proppant flowback issues during post-fracturing treatments and production, self-healing elastomer modified proppants (SMPs) are proposed. Owing to their inherent self-aggregation behavior, the SMPs can aggregate together spontaneously to prevent proppant flowback and increase the pack porosity. It is noteworthy that the SMPs have a firm and dry self-healing elastomer (SE) coating, making their storage, transport and use as conventional proppants possible. The SE synthesized through polymerization is rich in amidogens and carbonyl groups as characterized by Fourier transform infrared spectroscopy and the proton nuclear magnetic resonance. Thermal and thermomechanical properties of the SE coating are revealed by the thermogravimetric analysis, the differential scanning calorimetry and the rheological tests. The self-aggregation behavior of the SMPs is demonstrated by the adhesion force tests. The reversible hydrogen bonding interactions in SE coating contribute to the self-aggregation behavior of the SMPs, which is revealed by the thixotropy test and the FTIR analysis at different temperatures. With the self-aggregation behavior, the crushed proppants can aggregate in situ to form a stable structure again and therefore reduce the threat of narrowing down the fracture and proppant flowback, which has an important practical significance during oil and gas production.