Development of metakaolin and geopolymer proppants with nanocarbon materials

Abstract

From the first hydraulic fracturing in the 40's until nowadays, the techniques of each process step have evolved significantly. This study presents a new approach on the development of metakaolin (MK) and geopolymer based proppant with and without nanocarbon materials such as multi-walled carbon nanotubes and graphene oxide. For manufacturing the microspheres, the chosen method was intensive mixing of raw material with dispersed nanocarbons followed by sintering metakaolin and curing the geopolymer using an alkaline medium (NaOH). Compression mechanical tests, bulk density, turbidity, and K&S method analysis were made following API RP 19C standard. The sample containing 4.3 M NaOH to produce alkali-activated metakaolin sintered at 1300 ºC for 2 h presented higher mechanical resistance generating 2.4% of fines at 3 K (3000 psi). The geopolymer samples showed higher crushing strength and lower bulk density when compared to the MK samples without heat treatment. Furthermore, reduced graphene was produced and incorporated into activated MK. Morphology and presence of carbon nanostructures on the proppants were evaluated by scanning electron microscopy. Crushing test reached 3 K enabling it to be used as a ceramic synthetic proppant containing carbon nanomaterials.