Abstract: Method for performing step rate tests on injection wells, including inserting a portable pumping unit to receive the water or other fluid normally injected into the well and controlling its pressure, and then increasing the pressure of the injection fluid to a predetermined pressure by use of the portable pumping unit to determine fluid flow at said predetermined pressure, the fluid at the predetermined pressure being pumped continuously until a stable flow rate is achieved. The procedure is repeated for plural stepwisely increased pressure points at each side of the fracture pressure, whereby the fracture pressure is accurately determined.