Pressure pumping is a process of injecting pressurized fluids ( fracturing fluid, acid, cement), during different phases of hydrocarbon production. Pressure pumping is used on old and new wells, during completion, intervention and stimulation.
Hydraulic fracturing is one of the most used methods in pressure pumping. Hydraulic fracturing is a process of pumping water, sand and chemicals underground, to have enough pressure to break the rock. It is mainly used in formations that have a lower ability to transit fluids (aka permeability).