Drilling Pump — Key Performance Parameters 1. Rated Working Pressure: The maximum discharge pressure at which the drilling pump is allowed to work continuously over long periods, expressed in MPa. Deep-well drilling requires very high pressure to push the drilling fluid to the bottom hole; the pressure ratings commonly configured for rig drilling pumps are 35 MPa, 50 MPa, and above. The deeper the well and the greater the circulation resistance, the higher the pressure