US Patent 9611728 Cold weather package for oil field hydraulics

A hydraulic fracturing system includes an electrically powered pump that pressurizes fluid, which is piped into a wellbore to fracture a subterranean formation. System components include a fluid source, an additive source, a hydration unit, a blending unit, a proppant source, and a fracturing pump. The system includes heaters for warming hydraulic fluid and/or lube oil. The hydraulic fluid is used for operating devices on the blending and hydration units. The lube oil lubricates and cools various moving parts on the fracturing pump.