The US oil industry is a multibillion-dollar industry and hydraulic fracturing has been a growing factor in US oil production. Back in 2000 hydraulic fracturing, or fracking as it’s known made up only 2% of US oil production. That equated to about 23,000 fracking wells producing 102,000 barrels/day. Fast forward to today and there are over 300,000 fracking wells producing 4.3 million barrels/day. In a little more than ten years the US has grown to be one of the top oil producers in the world only trailing behind Russia and Saudi Arabia.
As the fracking industry expanded, the demand for frac sand has increased as well. Frac sand consists of high-purity quartz (silicon) sand. Quartz sand is durable, round, and crush resistant; all qualities needed in the fracking process. The frac sand industry continues to grow as fracking increases in the US; driven by the increase in global energy consumption.
There are several traits that classify frac sand as high quality. Premium frac sand needs to consist of at least 90% quartz in the sand. Most high-quality sand falls between 95-99% quartz. The quartz grains also need to be homogenous in size; ideally between 0.1 to > 2mm. Larger grains allow for better permeability while smaller grains have increased strength under high pressure. Another factor is the roundness/sphericity of the grains. Round grains allow for better permeability between grains.
Frac sand also needs to be able to perform under high pressure. The high crush resistance of silica allows the sand to help keep fractures open under high pressure and temperatures. Frac sand high in silica will have low solubility. Poor quality sand will have too much soluble material and will not be able to support the fractures as effectively.
The final two traits are turbidity and bulk density/specific gravity in comparison to silica. Turbidity references the absence of clay, silt, and other impurities in the sand. The bulk density/specific gravity to silica is similar to turbidity. Frac sand with specific gravity equal or closer to silica will have a higher percentage of silica in the sand.
Silica is the most common element in the Earth’s crust. This doesn’t mean that every location is ideal for mining frac sand. Sandstone makes a good source of frac sand due to having good friability. Loose deposits are easier to excavate with shovels or moving equipment. Blasting the stone can actually be detrimental as blasting can reduce sphericity and roundness of the silica sand. Being near the surface also reduces the cost of removing material on top of the frac sand deposits. The last piece is the deposit’s location to transportation routes. The shorter the distance to the fracking site, the lower the costs to transport it.
The fracking industry will continue to expand as energy demands grow worldwide. The frac sand industry alone is already a billion-dollar industry and shows no sign of slowing. Frac equipment in one job alone will few a few thousand tons of sand. As the industry expands, the less reliant we become on foreign oil and gas.