Compression and crushing behavior of ceramic proppants and sand under high stresses

Proppants play a pivotal role in hydraulic fracturing treatment for oil and gas production in low-permeability hydrocarbon-bearing formations. This paper experimentally investigates the compression and crushing behavior of engineered ceramic proppants and frac sand. Proppants' time-independent and time-dependent mechanical behavior was quantified by conducting displacement-controlled diametrical compression tests and step-wise creep tests on single proppant grains, as well as 1-D compression tests on proppant grain packs. Rock-proppant interaction tests were also performed to mimic the proppants' behavior in a rock fracture under reservoir stresses. Individual ceramic proppants showed higher time-independent crushing resistance than the frac sand. Proppant grains with surface asperities were inferred to be more susceptible to creep behavior under sustained load due to the progressive damage of surface asperities. 1-D compression tests revealed that the frac sand is more compressible and crushing-prone compared with the ceramic proppants. Severe grain crushing and moderate grain embedment were observed in rock-proppant interaction tests under in-situ stresses.