Ultra-light weight proppant of diatomite-reinforced poly(methyl methacrylate-co-styrene) enabling high compressive strength, heat and acid resistance toward hydraulic fracturing

Abstract

The growing emphasis on environmental protection in petroleum exploitation results in a high demand for ultra-lightweight (ULW) proppants. This work involves fabricating ULW proppant utilizing suspension polymerization, in which alkyl chain decorated natural clay diatomite (Dia) is incorporated into poly(methyl methacrylate-co-styrene) (poly(MMA-co-St)). The obtained poly(MMA-co-St)/Dia composite beads exhibit a low apparent density ranging from 1.025 to 1.213 g cm−3, and show an impressively low crushing rate of 0.99 % under 52 MPa. The rigid and thermally stable Dia crosslinks with poly(MMA-co-St) matrix, which increases the network density and restricts the movement of the molecular chain, thereby enhancing both the mechanical and thermal stability of poly(MMA-co-St)/Dia. Additionally, these composite beads display minimal acid solubility and low turbidity. The exceptional mechanical and thermal stability (attributed to the reinforcement effect and thermal barrier effect of inorganic Dia, as well as the synergistic effect of the copolymerization of MMA and styrene), along with the low acid solubility and turbidity, enabling the poly(MMA-co-St)/Dia composite to replace traditional proppants and be applied in hydraulic fracturing for oil and gas exploitation.