API 19C

Proppants Used in Hydraulic Fracturing and Gravel

Applicability: Applies to all proppant materials used in hydraulic fracturing and gravel-packing operations in oil and gas wells, including natural silica sand, resin-coated sand, and manufactured ceramic proppants across the full range of mesh sizes used in industry. The standard does not cover well completion fluids, fracturing chemicals, or non-solid completion materials. It is the primary industry reference for proppant qualification and procurement testing.

Purpose: Specifies standardized test procedures for measuring the physical and performance properties of proppants, including particle size distribution, sphericity and roundness, crush resistance under closure stress, turbidity, acid solubility, bulk density, and apparent specific gravity. These measured properties allow engineers and operators to select appropriate proppants for specific downhole conditions and predict fracture conductivity and pack longevity. Results are used directly to qualify proppants against operator specifications and ensure consistent performance in hydraulic fracture stimulation.